Recyclable Ni-Containing Coordination Polymer as an Efficient Catalyst for the Synthesis of Oxindole and Quinoline Derivatives through the Borrowing Hydrogen Strategy

Round 1

Reviewer 1 Report

Very well written manuscript. 

Only few things need to be revised. 

- Page 11; 3.2 should be procedure for alkylation of 2-oxindole.  Suggestion is remove topic 3.2 and move lines 267-284 to line after 242.

CHLOROFORM-D should be CDCl₃  and DMSO-D should be DMSO-d6

For known compounds (H₂CIA, compounds 3 and 6), references should be cited. 

HRMS data are required for new synthetic compounds (compounds 3 and 6). 

 

Author Response

Dear Editor and Reviewers,

Thank you very much for giving us the opportunity to revise the manuscript (catalysts-2514205). Enclosed please find our revised manuscript “Recyclable Ni-containing coordination polymer as efficient catalysts for the synthesis of oxindole and quinoline derivatives through borrowing hydrogen strategy” by Jiahao Li ^†, Jiajie Tang ^†, Likui Wang, Dawei Wang*, and Zheng-Chao Duan*.

We would like to express our heartfelt thanks for Editorial Office and four Reviewers. We have revised the manuscript according to the comments and suggestions, these questions were answered one by one.

 

Response to Reviewer 1

We are very grateful for the comments of Reviewer 1 (Very well written manuscript. Only few things need to be revised.)

1. For the 1st question of “Page 11; 3.2 should be procedure for alkylation of 2-oxindole. Suggestion is removing topic 3.2 and move lines 267-284 to line after 242.”.

Response: According to the suggestion of Reviewer 1, topic 3.2 has been moved to line after 242.

2. For the 2nd question of “CHLOROFORM-D should be CDCl₃ and DMSO-D should be DMSO-d₆.”.

Response: We thank Reviewer 1 for this suggestion, all “CHLOROFORM-D and DMSO-D” in the manuscript was corrected as “CDCl₃ and DMSO-d₆^” , respectively.

3. For the 3rd question of “For known compounds (H₂CIA, compounds 3 and 6), references should be cited. HRMS data are required for new synthetic compounds (compounds 3 and 6).”

Response: According to the suggestion of Reviewer 1, All the references (For known compounds) were added in the supporting information part. As follows:

1. Hu, X.; Zhu, H.; Sang, X.; Wang, D. Design and Synthesis of Zirconium-Containing Coordination Polymer Based on Unsymmetric Indolyl Dicarboxylic Acid and Catalytic Application on Borrowing Hydrogen Reaction. Synth. Catal. 2018, 360, 4293-4300; DOI:10.1002/adsc.201800875.
2. Saini, P.; Dolui, P.; Nair, A.; Verma, A.; Elias, A.J. A Bench-stable 8-Aminoquinoline Derived Phosphine-free Manganese (I)-Catalyst for Environmentally Benign C(alpha)-Alkylation of Oxindoles with Secondary and Primary Alcohols. Asian J. 2023, 18, e202201148; DOI:10.1002/asia.202201148.
3. Dambatta, M.B.; Polidano, K.; Northey, A.D.; Williams, J.M.J.; Morrill, L.C. Iron-Catalyzed Borrowing Hydrogen C-Alkylation of Oxindoles with Alcohols. ChemSusChem 2019, 12, 2345-2349; DOI:10.1002/cssc.201900799.
4. Wu, Q.; Pan, L.; Du, G.; Zhang, C.; Wang, D. Preparation of pyridyltriazole ruthenium complexes as effective catalysts for the selective alkylation and one-pot C–H hydroxylation of 2-oxindole with alcohols and mechanism exploration. Chem. Front. 2018, 5, 2668-2675; DOI:10.1039/c8qo00725j.
5. Grigg, R.; Whitney, S.; Sridharan, V.; Keep, A.; Derrick, A. Iridium catalysed C-3 alkylation of oxindole with alcohols under solvent free thermal or microwave conditions. Tetrahedron 2009, 65, 4375-4383; DOI:10.1016/j.tet.2009.03.065.
6. Ghosh, A.; Bera, A.; Banerjee, D. Nickel Catalyzed Alkylation of Oxindoles with Alkyl Alcohols. ChemCatChem 2023, 15, e202201433; DOI:10.1002/cctc.202201433.
7. Yu, K.; Chen, Q.; Liu, W. Iron-catalysed quinoline synthesis via acceptorless dehydrogenative coupling. Chem. Front. 2022, 9, 6573-6578; DOI:10.1039/d2qo01386j.
8. Hao, Z.; Zhou, X.; Ma, Z.; Zhang, C.; Han, Z.; Lin, J.; Lu, G.L. Dehydrogenative Synthesis of Quinolines and Quinazolines via Ligand-Free Cobalt-Catalyzed Cyclization of 2-Aminoaryl Alcohols with Ketones or Nitriles. J. Org. Chem. 2022, 87, 12596-12607; DOI:10.1021/acs.joc.2c00734.
9. Jana, A.; Kumar, A.; Maji, B. Manganese catalyzed C-alkylation of methyl N-heteroarenes with primary alcohols. Chem. Commun. 2021, 57, 3026-3029; DOI:10.1039/d1cc00181g.

For new synthetic compounds 3h, the HRMS were added. As follows:

3-(4-(Tert-butyl)benzyl)indolin-2-one (3h).

yellow solid; ¹H NMR (400 MHz, CDCl₃) δ 9.36 (s, 1H), 7.31 (d, J = 8.3 Hz, 2H), 7.15 (t, J = 8.0 Hz, 3H), 6.92 (t, J = 7.7 Hz, 2H), 6.75 (d, J = 7.5 Hz, 1H), 3.76 (dd, J = 9.7, 4.3 Hz, 1H), 3.50 (dd, J = 13.8, 4.3 Hz, 1H), 2.85 (dd, J = 13.8, 9.6 Hz, 1H), 1.30 (s, 9H). ¹³C NMR (101 MHz, CDCl₃) δ 180.45, 149.65, 141.71, 135.01, 129.43, 129.17, 128.05, 125.40, 124.95, 122.13, 110.05, 47.80, 36.33, 34.55, 31.49. HRMS Calculated for C₁₉H₂₂NO [M+H]⁺ 280.1701, found 280.1702.

 

Response to Reviewer 2

We are very grateful for the recommendations of Reviewer 2 (The manuscript describes the preparation, characterization of polymer supported heterogeneous Ni-CIA catalyst and its application in the synthesis of oxindoles and quinolines via borrowing hydrogen reactions. Besides enabling the synthesis of the two kinds of products with broad scope, the catalyst also displays evidently higher catalytic activity than simple Ni-salts, and advantage in recovery. The work is recommended for publication in Catalysts after revision by addressing a few issues.)

1. For the 1st question of “In the introduction, the authors have discussed the biologically active oxindoles. As the other class of products reported in the manuscript, the quinolines should also be discussed in the area of biological & pharmaceutical functions. For some examples: Org. Biomol. Chem. 2022, 20, 4385; Chin. J. Org. Chem. 2022, 42, 2947; Catalysts 2022, 12, 1468; Curr. Med. Chem. 2017, 24, 2241.”.

Response: According to the suggestion of Reviewer 2, All the four references were added in ref 5-8. As follows:

5. Huang, L.; Yang, L.; Wan, J.P.; Zhou, L.; Liu, Y.; Hao, G. Metal-free three-component assemblies of anilines, alpha-keto acids and alkyl lactates for quinoline synthesis and their anti-inflammatory activity. Biomol. Chem. 2022, 20, 4385-4390; DOI:10.1039/d2ob00661h.
6. Liu, H.; Zeng, X.-Q.; Zuo, H.-W.; Zhang, N.; Huang, Z.-Y. Design, Synthesis and Seed Germination Inhibition Activity of Quinoline-6-sulfonamide Compounds. J. Org. Chem. 2022, 42, 2947-2953; DOI:10.6023/cjoc202206040.
7. Moutaouakil, M.; Tighadouini, S.; M. Almarhoon, Z.; I. Al-Zaben, M.; Ben Bacha, A.; H. Masand, V.; Jamaleddine, J.; Saddik, R. Quinoline Derivatives with Different Functional Groups: Evaluation of Their Catecholase Activity. Catalysts 2022, 12, 1468; DOI:10.3390/catal12111468.
8. Hu, C.; Lu, L.; Wan, J.P.; Wen, C. The Pharmacological Mechanisms and Therapeutic Activities of Hydroxychloroquine in Rheumatic and Related Diseases. Med. Chem. 2017, 24, 2241-2249; DOI:10.2174/0929867324666170316115938.
9. For the 2nd question of “The experimental for the recovery of Ni-CIA catalyst should be provided in the revised manuscript.”.

Response: According to the suggestions of Reviewer 2. We provided that the characterization of the spent catalyst by SEM in the revised manuscript. It could be seen from the figure that the morphology of the catalyst Ni-CIA had no obvious change and it still had a a slice layer stacked combination structure.

One sentence was added to explain this. As follows: (Page 14, lines 276-280)

After recycling experiments, the Ni-CIA catalyst was collected and characterized by scanning electron microscope (SEM) again after washed three times with methanol, deionized water, ethanol, and dried at 80 ^oC (Figure S1). From the figure, no significant change in the morphology of the catalyst Ni-CIA is seen, retaining its slice layer stacked combination structure.

 

Figure S1. (a) and (b) SEM image of Ni-CIA after being recycled five times.

3. For the 3rd question of “Table 2, the reaction using simple alkyl alcohol such as propanol should be conducted and discussed.”.

Response: According to the suggestions of Reviewer 2. We try to expand the alkylation of aliphatic alcohols and alicyclic alcohol with 2-oxindole. The results showed that the reaction could take place smoothly and the corresponding desired product could be obtained in moderate to good yields.

Two sentences were added to explain this. As follows: (Page 6, lines 149-153)

The scope was further extended to linear aliphatic secondary alcohols. Interestingly, aliphatic alcohols were also effective for the alkylation of 2-oxindole to offer the corresponding products 3q-3s in moderate yields. Meanwhile, alicyclic alcohol (cyclopropane methanol 2t) was also effective in yielding the corresponding products 3-(cyclopropyl methyl)indolin-2-one 3t in good yields.

4. For the 4th question of “Scheme 4, the mechanism for the reactions toward quinoline synthesis should also be included.”.

Response: As suggested by Reviewer 2, We have added a series of control experiments to the synthesis of quinoline derivatives and proposed possible reaction mechanisms in the revised manuscript, As follows: (Page 10, lines 218-235)

Subsequently, to understand the mechanism of 6a formation, a series of control experiments were performed (Scheme 4). Initially, In the presence of BTH and TEMPO, this transformation proceeded well, and the yield of 6a was only slightly decreased. This rule out the involvement of an organic radical intermediate during this reaction, as it is widely accepted that the capture of key intermediate is an efficient and reliable way to explain what happened in this reaction process. The reaction of only o-aminobenzyl alcohol 4a give 2-aminobenzaldehyde 4a’ in 58% isolated yield under the standard conditions (i). Reaction of 2-aminobenzaldehyde 4a’ and acetophenone 5a afforded the 2-phenylquinoline 6a in 94% yield in absence of catlayst Ni-CIA, implying that the carbonyl compound (2-aminobenzaldehyde 4a’) is the intermediate and Cs₂CO₃ played a significant role for deprotonation of alcohols and condensation (ii). Notably, the formation of 2-phenylquinoline 6a was not observed from the coupling of o-aminobenzyl alcohol 4a with acetophenone 5a in the absence of catalyst (iii). The above control experiment results together confirmed that the catalyst Ni-CIA facilitated the dehydrogenation of the o-aminobenzyl alcohol 4a, and that 2-aminobenzaldehyde 4a’ was the intermediate in this process.

Scheme 4. Mechanism exploration experiments for the synthesis of quinolines.

(Page 12, lines 247-259):

Similarly, A plausible mechanism for the Ni-catalyzed synthesis of quinoline derivatives via the dehydrogenative coupling of o-aminobenzyl alcohol 4a with acetophenone 5a is shown in Scheme 6. Firstly, the deprotonation of 4a assisted by the Cs₂CO₃ produces the active species C, which then participate in this catalytic cycle. Next , C reacted with Ni-CIA to afford the alkoxy intermediate D. The intermediate D undergoes β-hydride elimination of alkoxide to produce the dehydrogenated product 2-aminobenzaldehyde 4a’ with the formation of [Ni-H] species. Subsequently, 2-aminobenzaldehyde 4a’ undergoes base-catalyzed cross-aldol condensation reaction with acetophenone 5a to form an α, β -unsaturated ketone. Finally, the α, β -unsaturated ketone reacts via intramolecular cyclization to give the product 6a.

Scheme 6. Proposed possible reaction mechanism for the synthesis of quinolines.

5. For the 5th question of “Closely related works on dehydrogenative annulation for quinoline synthesis should be cited: Green Chem. 2020, 22, 3074; Green Synth. Catal. 2022, 3, 95-101 etc.”.

Response: According to the suggestion of Reviewer 2, All the two references were added in ref 68-69. As follows:

68. Yang, L.; Wan, J.-P. Ethyl lactate-involved three-component dehydrogenative reactions: biomass feedstock in diversity-oriented quinoline synthesis. Green Chem. 2020, 22, 3074-3078; DOI:10.1039/d0gc00738b.
69. Li, R.; Jiang, S.; Zheng, H.; Lei, H.; Huang, Z.; Chen, S.; Deng, G.-J. Iron-catalyzed indolo[2,3-c]quinoline synthesis from nitroarenes and benzylic alcohols/aldehydes promoted by elemental sulfur. Green Synth. Catal. 2022, 3, 95-101; DOI:10.1016/j.gresc.2021.11.006.

 

Response to Reviewer 3

We are very grateful for the recommendations of Reviewer 3.

1. For the 1st question of “All abbreviations such as Ni-CIA and TLC must be given at their first uses.”.

Response: As suggested by Reviewer 3, We have checked the manuscript and added the full name before the abbreviation at their first uses.

List of abbreviations as follows:

Fourier transform infrared (FT-IR); powder X-ray diffraction (XRD); scanning electron microscope (SEM); X-ray photoelectron spectrometry (XPS); energy-dispersive X-ray spectroscopy (EDS); Thermal gravimetric analysis (TGA); Coordination polymers (CPs); Ni-CIA (Ni-indolyl dicarboxylic acid coordination polymer); H₂CIA (indolyl dicarboxylic acid ligand); N,N-dimethylformamide (DMF); thin layer chromatography (TLC).

2. For the 2nd question of “Authors need to check formats of the manuscript, including line spacing, and revise accordingly.”.

Response: According to the suggestion of Reviewer 3. We have checked the format of the manuscript and made corresponding modifications.

3. For the 3rd question of “Section 3 (Materials and Methods) must be switched with Section 2.”.

Response: We thank Reviewer 3 for this suggestion, Section 3 (Materials and Methods) has been switched with Section 2.

4. For the 4th question of “Countries of manufacturer for chemicals and equipment must be provided.”.

Response: According to the suggestion of Reviewer 3, we added the explanation of reagents and solvents. As follows:

FT-IR spectra (Thermo Fisher Co, USA).

SEM image and EDS spectra (Hitachi, Japan).

TG analysis was carried out using a STA409 (Mettler-Toli, Switzerland).

XRD patterns were collected on a Bruker D8 (Germany).

XPS (ESCALAB 250Xi, Thermo Fisher Co, USA).

¹H NMR and ¹³C NMR spectra were obtained on Bruker Advance III HD (Switzerland).

The chemicals were used as received: methyl indole-5-carboxylate (>98%, Adamas), methyl 2-bromoacetate (>98%, Adamas), anhydrous potassium carbonate (K₂CO₃, >99%, Sinopharm), anhydrous magnesium sulfate (MgSO₄, >99%, Sinopharm), acetonitrile (MeCN, 99.9%, Sigma), LiOH·H₂O (>95%, Sinopharm), Tetrahydrofuran (THF, 99.9%, Sigma), NiCl₂^.6H₂O (Adamas), N,N-dimethylformamide (DMF, 99.9%, Sigma), ethanol (99%, Sigma), KOtBu (>98%, Sinopharm), 2-oxindole derivative (>98%, Adamas), benzyl alcohol derivatives (>99%, Adamas), o-aminobenzyl alcohol (99%, Sigma), acetophenone derivatives (>99%, Adamas), Unless otherwise noted, all commercial reagents and solvents were obtained from the commercial provider and used without further purification.

5. For the 5th question of “Section 4 must be moved to supplementary or authors need to find better way to represent the information.”.

Response: According to the suggestions, Section 4 were transferred into the supporting information part from manuscript (main text).

6. For the 6th question of “Conclusion must be improved. Main findings as well as their implications should be included in the conclusion.”.

Response: We thank Reviewer 3 again for this, we have made modifications to the conclusion section of the manuscript by incorporating the main conclusions of the experiment and relevant content on its impact. As follows:

In summary, we herein report a simple, effective, and reusable heterogeneous coordination polymer Ni-CIA catalyst for promoting the synthesis of oxindole and quinoline derivatives through the borrowing hydrogen strategy. The slice layer stacked combination structure of the catalyst can effectively promote the ion diffusion and accelerate catalytic mass transfer during the catalytic reaction. Moreover, various primary alcohol and acetophenone substrates were tested under optimized reaction conditions to form the desired compounds in moderate to excellent yields. After that, the mechanism explorations including control experiments were conducted to clarify the effect of different substituents and cooperative effects were conducted to clarify these transformations. The above experiment results confirmed that catalysis with Ni-CIA facilitates the dehydrogenation of the benzyl alcohol 2a and o-aminobenzyl alcohol 4a, revealing that the reaction followed hydrogen-borrowing mechanism, thus proposed the possible reaction mechanism for the two types of reactions. Finally, the recycled experiments showed that the Ni-CIA catalyst had fine stability. In particular, it was showed that no significant reduction in activity was observed for Ni-CIA after five runs and no significant changes in its surface morphology of the catalyst. This catalytic system is shown as a much greener way for the synthesis of oxindole and quinoline derivatives, in accordance with the principles of sustainable development and atom economy, making it highly promising for organic catalysis.

7. For the 7th question of “English must be carefully checked and revised. Some sentences were hard to understand and awkward.”.

Response: According to the suggestion of Reviewer 3, we checked this manuscript carefully and the errors were corrected, as follows:

(1) (Page 1, line 13) “have” was corrected as “has”.

(2) (Page 1, line 17) “were revealed to have” was corrected as “reveals”.

(3) (Page 1, line 21) “the” was added.

(4) (Page 1, line 31) “with” was added.

(5) (Page 1, line 38) “which” was deleted.

(6) (Page 1, line 41) “a” was added.

(7) (Page 1, line 45) “and” was corrected as “which”.

(8) (Page 1, line 55) “separating” was corrected as “separation”.

(9) (Page 1, line 56) “several” was corrected as “a number of”.

(10) (Page 1, line 56) “with” was added.

(11) (Page 1, line 57) “could be” was added.

(12) (Page 4, line 134) “carefully” was deleted.

(13) (Page 4, line 141) “and” was deleted.

(14) (Page 5, line 148) “that” was added.

(15) (Page 5, line 149) “the” was deleted.

(16) (Page 5, line 152) “are observed” was added.

(17) (Page 5, line 158) “was” was corrected as “has a”.

(18) (Page 5, line 160) “reaction” was corrected as “process”.

(19) (Page 6, line 182) “analyze” was corrected as “analyzed”.

(20) (Page 6, line 185) “to” was added.

(21) (Page 6, line 185) “disintegrating” was corrected as “disintegrate”.

(22) (Page 7, line 198) “the” was added.

(23) (Page 7, line 198) “afford” was corrected as “afforded”.

(24) (Page 7, line 201) “and” was added.

(25) (Page 8, line 217) “groups” was deleted.

(26) (Page 8, line 223) “are” was added.

(27) (Page 10, line 239) “the” was deleted.

(28) (Page 10, line 240) “are” was corrected as “is”.

(29) (Page 10, line 244) “a” was added.

(30) (Page 11, line 257) “yield” was corrected as “yields”.

(31) (Page 12, line 270) “the” was added.

(32) (Page 12, line 270) “has” was deleted.

(33) (Page 12, line 271) “this” was corrected as “the”.

(34) (Page 13, line 278) “group” was deleted.

(35) (Page 13, line 279) “group” was corrected as “groups”.

(36) (Page 13, line 281) “found to be” was added.

(37) (Page 13, line 281) “the” was added.

(38) (Page 13, line 283) “group” was added”.

(39) (Page 14, line 297) “intermediate” was corrected as “intermediates”.

(40) (Page 14, line 297) “to form” was corrected as “affords”.

(41) (Page 15, line 325) “undergo” was corrected as “undergoes”.

(42) (Page 15, line 326) “and” was corrected as “which”.

(43) (Page 15, line 327) “participate” was corrected as “participates”.

(44) (Page 15, line 328) “and” was corrected as “which”.

(45) (Page 15, line 328) “formation of” was deleted.

(46) (Page 15, line 352) “following” was corrected as “followed”.

(47) (Page 15, line 352) “and” was added”.

(48) (Page 15, line 353) “respectively” was added”.

(49) (Page 15, line 352) “drying” was corrected as “dried”.

(50) (Page 15, line 355) “the” was added”.

(51) (Page 15, line 356) “showed” was corrected as “shown”.

 

Response to Reviewer 4

We are very grateful for the recommendations of Reviewer 4.( The authors further expanded this synthetic method to the construction of quinoline motif. The investigation was carefully achieved, and the paper is well written. The mechanism is suitably proposed, and mechanistic studies supported this hypothesis. I would recommend publication of this manuscript in catalysts.

1. For the 1st question of “Page 2, line 55: The word “Indolyl” should be corrected to “indolyl”.”.

Response: We thank Reviewer 4 very much for helping us correct the mistakes and errors, (Page 2, line 55) “Indolyl” was corrected as “indolyl”

2. For the 2nd question of “Page 4, line 118: The word “87%” should be corrected to “84%” according to the result of entry 5.”.

Response: We thank Reviewer 4 again for this, (Page 4, line 118) “87%” was corrected as “84%”.

3. For the 3rd question of “Page 5, Table 1: The authors should write the reaction temperature. In entry 11, the reaction temperature is unclear (111 ^oC: boiling point of toluene ?).”.

Response: We thank Reviewer 4 very much for this comment. we have revised the reaction temperature in the manuscript (the reaction temperature is 120 ºC).

4. For the 4th question of “Page 6, line 150: The word “moderate” should be corrected to “good (or excellent).”.

Response: We thank Reviewer 4 again for helping us correct the mistakes and errors, (Page 6, line 150) “moderate” was corrected as “good”.

5. For the 5th question of “Page 6, line 159: Reference about the synthesis of quinoline derivatives should be cited (H. Hikawa and I. Azumaya et al. Asian J. Org. Chem. 2022, e202200510).”.

Response: According to the suggestion of Reviewer 4, the reference was added in ref 24. As follows:

24. Nakayama, T.; Harada, S.; Kikkawa, S.; Hikawa, H.; Azumaya, I. Palladium‐Catalyzed Dehydrogenative Synthesis of Imidazoquinolines in Water. Asian J. Org. Chem. 2022, 11, e202200510; DOI:10.1002/ajoc.202200510.

 

 

 

 

If you have any questions concerning the manuscript, please feel free to contact me.

Thank you very much for your consideration.

With best regards

 

Prof. Dawei Wang

Jiangnan University

1800 Lihu Road,

Wuxi, 214122, P. R. China

Email: [email protected]

 

Author Response File: Author Response.doc

Reviewer 2 Report

The manuscript describes the preparation, characterization of polymer supported heterogeneous Ni-CIA catalyst and its application in the synthesis of oxindoles and quinolines via borrowing hydrogen reactions. Besides enabling the synthesis of the two kinds of products with broad scope, the catalyst also displays evidently higher catalytic activity than simple Ni-salts, and advantage in recovery. The work is recommended for publication in Catalysts after revision by addressing a few issues.

1. In the introduction, the authors have discussed the biologically active oxindoles. As the other class of products reported in the manuscript, the quinolines should also be discussed in the area of biological & pharmaceutical functions. For some examples: Org. Biomol. Chem. 2022, 20, 4385; Chin. J. Org. Chem. 2022, 42, 2947; Catalysts 2022, 12, 1468; Curr. Med. Chem. 2017, 24, 2241 etc.

2. The experimental for the recovery of Ni-CIA catalyst should be provided in the revised manuscript.

3. Table 2, the reaction using simple alkyl alcohol such as propanol should be conducted and discussed.

4. Scheme 4, the mechanism for the reactions toward quinoline synthesis should also be included.

5. Closely related works on dehydrogenative annulation for quinoline synthesis should be cited: Green Chem. 2020, 22, 3074; Green Synth. Catal. 2022, 3, 95-101 etc.

Author Response

Dear Editor and Reviewers,

Thank you very much for giving us the opportunity to revise the manuscript (catalysts-2514205). Enclosed please find our revised manuscript “Recyclable Ni-containing coordination polymer as efficient catalysts for the synthesis of oxindole and quinoline derivatives through borrowing hydrogen strategy” by Jiahao Li ^†, Jiajie Tang ^†, Likui Wang, Dawei Wang*, and Zheng-Chao Duan*.

We would like to express our heartfelt thanks for Editorial Office and four Reviewers. We have revised the manuscript according to the comments and suggestions, these questions were answered one by one.

 

Response to Reviewer 1

We are very grateful for the comments of Reviewer 1 (Very well written manuscript. Only few things need to be revised.)

1. For the 1st question of “Page 11; 3.2 should be procedure for alkylation of 2-oxindole. Suggestion is removing topic 3.2 and move lines 267-284 to line after 242.”.

Response: According to the suggestion of Reviewer 1, topic 3.2 has been moved to line after 242.

2. For the 2nd question of “CHLOROFORM-D should be CDCl₃ and DMSO-D should be DMSO-d₆.”.

Response: We thank Reviewer 1 for this suggestion, all “CHLOROFORM-D and DMSO-D” in the manuscript was corrected as “CDCl₃ and DMSO-d₆^” , respectively.

3. For the 3rd question of “For known compounds (H₂CIA, compounds 3 and 6), references should be cited. HRMS data are required for new synthetic compounds (compounds 3 and 6).”

Response: According to the suggestion of Reviewer 1, All the references (For known compounds) were added in the supporting information part. As follows:

1. Hu, X.; Zhu, H.; Sang, X.; Wang, D. Design and Synthesis of Zirconium-Containing Coordination Polymer Based on Unsymmetric Indolyl Dicarboxylic Acid and Catalytic Application on Borrowing Hydrogen Reaction. Synth. Catal. 2018, 360, 4293-4300; DOI:10.1002/adsc.201800875.
2. Saini, P.; Dolui, P.; Nair, A.; Verma, A.; Elias, A.J. A Bench-stable 8-Aminoquinoline Derived Phosphine-free Manganese (I)-Catalyst for Environmentally Benign C(alpha)-Alkylation of Oxindoles with Secondary and Primary Alcohols. Asian J. 2023, 18, e202201148; DOI:10.1002/asia.202201148.
3. Dambatta, M.B.; Polidano, K.; Northey, A.D.; Williams, J.M.J.; Morrill, L.C. Iron-Catalyzed Borrowing Hydrogen C-Alkylation of Oxindoles with Alcohols. ChemSusChem 2019, 12, 2345-2349; DOI:10.1002/cssc.201900799.
4. Wu, Q.; Pan, L.; Du, G.; Zhang, C.; Wang, D. Preparation of pyridyltriazole ruthenium complexes as effective catalysts for the selective alkylation and one-pot C–H hydroxylation of 2-oxindole with alcohols and mechanism exploration. Chem. Front. 2018, 5, 2668-2675; DOI:10.1039/c8qo00725j.
5. Grigg, R.; Whitney, S.; Sridharan, V.; Keep, A.; Derrick, A. Iridium catalysed C-3 alkylation of oxindole with alcohols under solvent free thermal or microwave conditions. Tetrahedron 2009, 65, 4375-4383; DOI:10.1016/j.tet.2009.03.065.
6. Ghosh, A.; Bera, A.; Banerjee, D. Nickel Catalyzed Alkylation of Oxindoles with Alkyl Alcohols. ChemCatChem 2023, 15, e202201433; DOI:10.1002/cctc.202201433.
7. Yu, K.; Chen, Q.; Liu, W. Iron-catalysed quinoline synthesis via acceptorless dehydrogenative coupling. Chem. Front. 2022, 9, 6573-6578; DOI:10.1039/d2qo01386j.
8. Hao, Z.; Zhou, X.; Ma, Z.; Zhang, C.; Han, Z.; Lin, J.; Lu, G.L. Dehydrogenative Synthesis of Quinolines and Quinazolines via Ligand-Free Cobalt-Catalyzed Cyclization of 2-Aminoaryl Alcohols with Ketones or Nitriles. J. Org. Chem. 2022, 87, 12596-12607; DOI:10.1021/acs.joc.2c00734.
9. Jana, A.; Kumar, A.; Maji, B. Manganese catalyzed C-alkylation of methyl N-heteroarenes with primary alcohols. Chem. Commun. 2021, 57, 3026-3029; DOI:10.1039/d1cc00181g.

For new synthetic compounds 3h, the HRMS were added. As follows:

3-(4-(Tert-butyl)benzyl)indolin-2-one (3h).

yellow solid; ¹H NMR (400 MHz, CDCl₃) δ 9.36 (s, 1H), 7.31 (d, J = 8.3 Hz, 2H), 7.15 (t, J = 8.0 Hz, 3H), 6.92 (t, J = 7.7 Hz, 2H), 6.75 (d, J = 7.5 Hz, 1H), 3.76 (dd, J = 9.7, 4.3 Hz, 1H), 3.50 (dd, J = 13.8, 4.3 Hz, 1H), 2.85 (dd, J = 13.8, 9.6 Hz, 1H), 1.30 (s, 9H). ¹³C NMR (101 MHz, CDCl₃) δ 180.45, 149.65, 141.71, 135.01, 129.43, 129.17, 128.05, 125.40, 124.95, 122.13, 110.05, 47.80, 36.33, 34.55, 31.49. HRMS Calculated for C₁₉H₂₂NO [M+H]⁺ 280.1701, found 280.1702.

 

Response to Reviewer 2

We are very grateful for the recommendations of Reviewer 2 (The manuscript describes the preparation, characterization of polymer supported heterogeneous Ni-CIA catalyst and its application in the synthesis of oxindoles and quinolines via borrowing hydrogen reactions. Besides enabling the synthesis of the two kinds of products with broad scope, the catalyst also displays evidently higher catalytic activity than simple Ni-salts, and advantage in recovery. The work is recommended for publication in Catalysts after revision by addressing a few issues.)

1. For the 1st question of “In the introduction, the authors have discussed the biologically active oxindoles. As the other class of products reported in the manuscript, the quinolines should also be discussed in the area of biological & pharmaceutical functions. For some examples: Org. Biomol. Chem. 2022, 20, 4385; Chin. J. Org. Chem. 2022, 42, 2947; Catalysts 2022, 12, 1468; Curr. Med. Chem. 2017, 24, 2241.”.

Response: According to the suggestion of Reviewer 2, All the four references were added in ref 5-8. As follows:

5. Huang, L.; Yang, L.; Wan, J.P.; Zhou, L.; Liu, Y.; Hao, G. Metal-free three-component assemblies of anilines, alpha-keto acids and alkyl lactates for quinoline synthesis and their anti-inflammatory activity. Biomol. Chem. 2022, 20, 4385-4390; DOI:10.1039/d2ob00661h.
6. Liu, H.; Zeng, X.-Q.; Zuo, H.-W.; Zhang, N.; Huang, Z.-Y. Design, Synthesis and Seed Germination Inhibition Activity of Quinoline-6-sulfonamide Compounds. J. Org. Chem. 2022, 42, 2947-2953; DOI:10.6023/cjoc202206040.
7. Moutaouakil, M.; Tighadouini, S.; M. Almarhoon, Z.; I. Al-Zaben, M.; Ben Bacha, A.; H. Masand, V.; Jamaleddine, J.; Saddik, R. Quinoline Derivatives with Different Functional Groups: Evaluation of Their Catecholase Activity. Catalysts 2022, 12, 1468; DOI:10.3390/catal12111468.
8. Hu, C.; Lu, L.; Wan, J.P.; Wen, C. The Pharmacological Mechanisms and Therapeutic Activities of Hydroxychloroquine in Rheumatic and Related Diseases. Med. Chem. 2017, 24, 2241-2249; DOI:10.2174/0929867324666170316115938.
9. For the 2nd question of “The experimental for the recovery of Ni-CIA catalyst should be provided in the revised manuscript.”.

Response: According to the suggestions of Reviewer 2. We provided that the characterization of the spent catalyst by SEM in the revised manuscript. It could be seen from the figure that the morphology of the catalyst Ni-CIA had no obvious change and it still had a a slice layer stacked combination structure.

One sentence was added to explain this. As follows: (Page 14, lines 276-280)

After recycling experiments, the Ni-CIA catalyst was collected and characterized by scanning electron microscope (SEM) again after washed three times with methanol, deionized water, ethanol, and dried at 80 ^oC (Figure S1). From the figure, no significant change in the morphology of the catalyst Ni-CIA is seen, retaining its slice layer stacked combination structure.

 

Figure S1. (a) and (b) SEM image of Ni-CIA after being recycled five times.

3. For the 3rd question of “Table 2, the reaction using simple alkyl alcohol such as propanol should be conducted and discussed.”.

Response: According to the suggestions of Reviewer 2. We try to expand the alkylation of aliphatic alcohols and alicyclic alcohol with 2-oxindole. The results showed that the reaction could take place smoothly and the corresponding desired product could be obtained in moderate to good yields.

Two sentences were added to explain this. As follows: (Page 6, lines 149-153)

The scope was further extended to linear aliphatic secondary alcohols. Interestingly, aliphatic alcohols were also effective for the alkylation of 2-oxindole to offer the corresponding products 3q-3s in moderate yields. Meanwhile, alicyclic alcohol (cyclopropane methanol 2t) was also effective in yielding the corresponding products 3-(cyclopropyl methyl)indolin-2-one 3t in good yields.

4. For the 4th question of “Scheme 4, the mechanism for the reactions toward quinoline synthesis should also be included.”.

Response: As suggested by Reviewer 2, We have added a series of control experiments to the synthesis of quinoline derivatives and proposed possible reaction mechanisms in the revised manuscript, As follows: (Page 10, lines 218-235)

Subsequently, to understand the mechanism of 6a formation, a series of control experiments were performed (Scheme 4). Initially, In the presence of BTH and TEMPO, this transformation proceeded well, and the yield of 6a was only slightly decreased. This rule out the involvement of an organic radical intermediate during this reaction, as it is widely accepted that the capture of key intermediate is an efficient and reliable way to explain what happened in this reaction process. The reaction of only o-aminobenzyl alcohol 4a give 2-aminobenzaldehyde 4a’ in 58% isolated yield under the standard conditions (i). Reaction of 2-aminobenzaldehyde 4a’ and acetophenone 5a afforded the 2-phenylquinoline 6a in 94% yield in absence of catlayst Ni-CIA, implying that the carbonyl compound (2-aminobenzaldehyde 4a’) is the intermediate and Cs₂CO₃ played a significant role for deprotonation of alcohols and condensation (ii). Notably, the formation of 2-phenylquinoline 6a was not observed from the coupling of o-aminobenzyl alcohol 4a with acetophenone 5a in the absence of catalyst (iii). The above control experiment results together confirmed that the catalyst Ni-CIA facilitated the dehydrogenation of the o-aminobenzyl alcohol 4a, and that 2-aminobenzaldehyde 4a’ was the intermediate in this process.

Scheme 4. Mechanism exploration experiments for the synthesis of quinolines.

(Page 12, lines 247-259):

Similarly, A plausible mechanism for the Ni-catalyzed synthesis of quinoline derivatives via the dehydrogenative coupling of o-aminobenzyl alcohol 4a with acetophenone 5a is shown in Scheme 6. Firstly, the deprotonation of 4a assisted by the Cs₂CO₃ produces the active species C, which then participate in this catalytic cycle. Next , C reacted with Ni-CIA to afford the alkoxy intermediate D. The intermediate D undergoes β-hydride elimination of alkoxide to produce the dehydrogenated product 2-aminobenzaldehyde 4a’ with the formation of [Ni-H] species. Subsequently, 2-aminobenzaldehyde 4a’ undergoes base-catalyzed cross-aldol condensation reaction with acetophenone 5a to form an α, β -unsaturated ketone. Finally, the α, β -unsaturated ketone reacts via intramolecular cyclization to give the product 6a.

Scheme 6. Proposed possible reaction mechanism for the synthesis of quinolines.

5. For the 5th question of “Closely related works on dehydrogenative annulation for quinoline synthesis should be cited: Green Chem. 2020, 22, 3074; Green Synth. Catal. 2022, 3, 95-101 etc.”.

Response: According to the suggestion of Reviewer 2, All the two references were added in ref 68-69. As follows:

68. Yang, L.; Wan, J.-P. Ethyl lactate-involved three-component dehydrogenative reactions: biomass feedstock in diversity-oriented quinoline synthesis. Green Chem. 2020, 22, 3074-3078; DOI:10.1039/d0gc00738b.
69. Li, R.; Jiang, S.; Zheng, H.; Lei, H.; Huang, Z.; Chen, S.; Deng, G.-J. Iron-catalyzed indolo[2,3-c]quinoline synthesis from nitroarenes and benzylic alcohols/aldehydes promoted by elemental sulfur. Green Synth. Catal. 2022, 3, 95-101; DOI:10.1016/j.gresc.2021.11.006.

 

Response to Reviewer 3

We are very grateful for the recommendations of Reviewer 3.

1. For the 1st question of “All abbreviations such as Ni-CIA and TLC must be given at their first uses.”.

Response: As suggested by Reviewer 3, We have checked the manuscript and added the full name before the abbreviation at their first uses.

List of abbreviations as follows:

Fourier transform infrared (FT-IR); powder X-ray diffraction (XRD); scanning electron microscope (SEM); X-ray photoelectron spectrometry (XPS); energy-dispersive X-ray spectroscopy (EDS); Thermal gravimetric analysis (TGA); Coordination polymers (CPs); Ni-CIA (Ni-indolyl dicarboxylic acid coordination polymer); H₂CIA (indolyl dicarboxylic acid ligand); N,N-dimethylformamide (DMF); thin layer chromatography (TLC).

2. For the 2nd question of “Authors need to check formats of the manuscript, including line spacing, and revise accordingly.”.

Response: According to the suggestion of Reviewer 3. We have checked the format of the manuscript and made corresponding modifications.

3. For the 3rd question of “Section 3 (Materials and Methods) must be switched with Section 2.”.

Response: We thank Reviewer 3 for this suggestion, Section 3 (Materials and Methods) has been switched with Section 2.

4. For the 4th question of “Countries of manufacturer for chemicals and equipment must be provided.”.

Response: According to the suggestion of Reviewer 3, we added the explanation of reagents and solvents. As follows:

FT-IR spectra (Thermo Fisher Co, USA).

SEM image and EDS spectra (Hitachi, Japan).

TG analysis was carried out using a STA409 (Mettler-Toli, Switzerland).

XRD patterns were collected on a Bruker D8 (Germany).

XPS (ESCALAB 250Xi, Thermo Fisher Co, USA).

¹H NMR and ¹³C NMR spectra were obtained on Bruker Advance III HD (Switzerland).

The chemicals were used as received: methyl indole-5-carboxylate (>98%, Adamas), methyl 2-bromoacetate (>98%, Adamas), anhydrous potassium carbonate (K₂CO₃, >99%, Sinopharm), anhydrous magnesium sulfate (MgSO₄, >99%, Sinopharm), acetonitrile (MeCN, 99.9%, Sigma), LiOH·H₂O (>95%, Sinopharm), Tetrahydrofuran (THF, 99.9%, Sigma), NiCl₂^.6H₂O (Adamas), N,N-dimethylformamide (DMF, 99.9%, Sigma), ethanol (99%, Sigma), KOtBu (>98%, Sinopharm), 2-oxindole derivative (>98%, Adamas), benzyl alcohol derivatives (>99%, Adamas), o-aminobenzyl alcohol (99%, Sigma), acetophenone derivatives (>99%, Adamas), Unless otherwise noted, all commercial reagents and solvents were obtained from the commercial provider and used without further purification.

5. For the 5th question of “Section 4 must be moved to supplementary or authors need to find better way to represent the information.”.

Response: According to the suggestions, Section 4 were transferred into the supporting information part from manuscript (main text).

6. For the 6th question of “Conclusion must be improved. Main findings as well as their implications should be included in the conclusion.”.

Response: We thank Reviewer 3 again for this, we have made modifications to the conclusion section of the manuscript by incorporating the main conclusions of the experiment and relevant content on its impact. As follows:

In summary, we herein report a simple, effective, and reusable heterogeneous coordination polymer Ni-CIA catalyst for promoting the synthesis of oxindole and quinoline derivatives through the borrowing hydrogen strategy. The slice layer stacked combination structure of the catalyst can effectively promote the ion diffusion and accelerate catalytic mass transfer during the catalytic reaction. Moreover, various primary alcohol and acetophenone substrates were tested under optimized reaction conditions to form the desired compounds in moderate to excellent yields. After that, the mechanism explorations including control experiments were conducted to clarify the effect of different substituents and cooperative effects were conducted to clarify these transformations. The above experiment results confirmed that catalysis with Ni-CIA facilitates the dehydrogenation of the benzyl alcohol 2a and o-aminobenzyl alcohol 4a, revealing that the reaction followed hydrogen-borrowing mechanism, thus proposed the possible reaction mechanism for the two types of reactions. Finally, the recycled experiments showed that the Ni-CIA catalyst had fine stability. In particular, it was showed that no significant reduction in activity was observed for Ni-CIA after five runs and no significant changes in its surface morphology of the catalyst. This catalytic system is shown as a much greener way for the synthesis of oxindole and quinoline derivatives, in accordance with the principles of sustainable development and atom economy, making it highly promising for organic catalysis.

7. For the 7th question of “English must be carefully checked and revised. Some sentences were hard to understand and awkward.”.

Response: According to the suggestion of Reviewer 3, we checked this manuscript carefully and the errors were corrected, as follows:

(1) (Page 1, line 13) “have” was corrected as “has”.

(2) (Page 1, line 17) “were revealed to have” was corrected as “reveals”.

(3) (Page 1, line 21) “the” was added.

(4) (Page 1, line 31) “with” was added.

(5) (Page 1, line 38) “which” was deleted.

(6) (Page 1, line 41) “a” was added.

(7) (Page 1, line 45) “and” was corrected as “which”.

(8) (Page 1, line 55) “separating” was corrected as “separation”.

(9) (Page 1, line 56) “several” was corrected as “a number of”.

(10) (Page 1, line 56) “with” was added.

(11) (Page 1, line 57) “could be” was added.

(12) (Page 4, line 134) “carefully” was deleted.

(13) (Page 4, line 141) “and” was deleted.

(14) (Page 5, line 148) “that” was added.

(15) (Page 5, line 149) “the” was deleted.

(16) (Page 5, line 152) “are observed” was added.

(17) (Page 5, line 158) “was” was corrected as “has a”.

(18) (Page 5, line 160) “reaction” was corrected as “process”.

(19) (Page 6, line 182) “analyze” was corrected as “analyzed”.

(20) (Page 6, line 185) “to” was added.

(21) (Page 6, line 185) “disintegrating” was corrected as “disintegrate”.

(22) (Page 7, line 198) “the” was added.

(23) (Page 7, line 198) “afford” was corrected as “afforded”.

(24) (Page 7, line 201) “and” was added.

(25) (Page 8, line 217) “groups” was deleted.

(26) (Page 8, line 223) “are” was added.

(27) (Page 10, line 239) “the” was deleted.

(28) (Page 10, line 240) “are” was corrected as “is”.

(29) (Page 10, line 244) “a” was added.

(30) (Page 11, line 257) “yield” was corrected as “yields”.

(31) (Page 12, line 270) “the” was added.

(32) (Page 12, line 270) “has” was deleted.

(33) (Page 12, line 271) “this” was corrected as “the”.

(34) (Page 13, line 278) “group” was deleted.

(35) (Page 13, line 279) “group” was corrected as “groups”.

(36) (Page 13, line 281) “found to be” was added.

(37) (Page 13, line 281) “the” was added.

(38) (Page 13, line 283) “group” was added”.

(39) (Page 14, line 297) “intermediate” was corrected as “intermediates”.

(40) (Page 14, line 297) “to form” was corrected as “affords”.

(41) (Page 15, line 325) “undergo” was corrected as “undergoes”.

(42) (Page 15, line 326) “and” was corrected as “which”.

(43) (Page 15, line 327) “participate” was corrected as “participates”.

(44) (Page 15, line 328) “and” was corrected as “which”.

(45) (Page 15, line 328) “formation of” was deleted.

(46) (Page 15, line 352) “following” was corrected as “followed”.

(47) (Page 15, line 352) “and” was added”.

(48) (Page 15, line 353) “respectively” was added”.

(49) (Page 15, line 352) “drying” was corrected as “dried”.

(50) (Page 15, line 355) “the” was added”.

(51) (Page 15, line 356) “showed” was corrected as “shown”.

 

Response to Reviewer 4

We are very grateful for the recommendations of Reviewer 4.( The authors further expanded this synthetic method to the construction of quinoline motif. The investigation was carefully achieved, and the paper is well written. The mechanism is suitably proposed, and mechanistic studies supported this hypothesis. I would recommend publication of this manuscript in catalysts.

1. For the 1st question of “Page 2, line 55: The word “Indolyl” should be corrected to “indolyl”.”.

Response: We thank Reviewer 4 very much for helping us correct the mistakes and errors, (Page 2, line 55) “Indolyl” was corrected as “indolyl”

2. For the 2nd question of “Page 4, line 118: The word “87%” should be corrected to “84%” according to the result of entry 5.”.

Response: We thank Reviewer 4 again for this, (Page 4, line 118) “87%” was corrected as “84%”.

3. For the 3rd question of “Page 5, Table 1: The authors should write the reaction temperature. In entry 11, the reaction temperature is unclear (111 ^oC: boiling point of toluene ?).”.

Response: We thank Reviewer 4 very much for this comment. we have revised the reaction temperature in the manuscript (the reaction temperature is 120 ºC).

4. For the 4th question of “Page 6, line 150: The word “moderate” should be corrected to “good (or excellent).”.

Response: We thank Reviewer 4 again for helping us correct the mistakes and errors, (Page 6, line 150) “moderate” was corrected as “good”.

5. For the 5th question of “Page 6, line 159: Reference about the synthesis of quinoline derivatives should be cited (H. Hikawa and I. Azumaya et al. Asian J. Org. Chem. 2022, e202200510).”.

Response: According to the suggestion of Reviewer 4, the reference was added in ref 24. As follows:

24. Nakayama, T.; Harada, S.; Kikkawa, S.; Hikawa, H.; Azumaya, I. Palladium‐Catalyzed Dehydrogenative Synthesis of Imidazoquinolines in Water. Asian J. Org. Chem. 2022, 11, e202200510; DOI:10.1002/ajoc.202200510.

 

 

 

 

If you have any questions concerning the manuscript, please feel free to contact me.

Thank you very much for your consideration.

With best regards

 

Prof. Dawei Wang

Jiangnan University

1800 Lihu Road,

Wuxi, 214122, P. R. China

Email: [email protected]

 

Author Response File: Author Response.doc

Reviewer 3 Report

1. All abbreviations such as Ni-CIA and TLC must be given at their first uses.

2. Authors need to check formats of the manuscript, including line spacing, and revise accordingly.

3. Section 3 (Materials and Methods) must be switched with Section 2.

4. Countries of manufacturer for chemicals and equipment must be provided.

5. Section 4 must be moved to supplementary or authors need to find better way to represent the information.

6. Conclusion must be improved. Main findings as well as their implications should be included in the conclusion.

English must be carefully checked and revised. Some sentences were hard to understand and awkward.

Author Response

Dear Editor and Reviewers,

Thank you very much for giving us the opportunity to revise the manuscript (catalysts-2514205). Enclosed please find our revised manuscript “Recyclable Ni-containing coordination polymer as efficient catalysts for the synthesis of oxindole and quinoline derivatives through borrowing hydrogen strategy” by Jiahao Li ^†, Jiajie Tang ^†, Likui Wang, Dawei Wang*, and Zheng-Chao Duan*.

We would like to express our heartfelt thanks for Editorial Office and four Reviewers. We have revised the manuscript according to the comments and suggestions, these questions were answered one by one.

 

Response to Reviewer 1

We are very grateful for the comments of Reviewer 1 (Very well written manuscript. Only few things need to be revised.)

1. For the 1st question of “Page 11; 3.2 should be procedure for alkylation of 2-oxindole. Suggestion is removing topic 3.2 and move lines 267-284 to line after 242.”.

Response: According to the suggestion of Reviewer 1, topic 3.2 has been moved to line after 242.

2. For the 2nd question of “CHLOROFORM-D should be CDCl₃ and DMSO-D should be DMSO-d₆.”.

Response: We thank Reviewer 1 for this suggestion, all “CHLOROFORM-D and DMSO-D” in the manuscript was corrected as “CDCl₃ and DMSO-d₆^” , respectively.

3. For the 3rd question of “For known compounds (H₂CIA, compounds 3 and 6), references should be cited. HRMS data are required for new synthetic compounds (compounds 3 and 6).”

Response: According to the suggestion of Reviewer 1, All the references (For known compounds) were added in the supporting information part. As follows:

1. Hu, X.; Zhu, H.; Sang, X.; Wang, D. Design and Synthesis of Zirconium-Containing Coordination Polymer Based on Unsymmetric Indolyl Dicarboxylic Acid and Catalytic Application on Borrowing Hydrogen Reaction. Synth. Catal. 2018, 360, 4293-4300; DOI:10.1002/adsc.201800875.
2. Saini, P.; Dolui, P.; Nair, A.; Verma, A.; Elias, A.J. A Bench-stable 8-Aminoquinoline Derived Phosphine-free Manganese (I)-Catalyst for Environmentally Benign C(alpha)-Alkylation of Oxindoles with Secondary and Primary Alcohols. Asian J. 2023, 18, e202201148; DOI:10.1002/asia.202201148.
3. Dambatta, M.B.; Polidano, K.; Northey, A.D.; Williams, J.M.J.; Morrill, L.C. Iron-Catalyzed Borrowing Hydrogen C-Alkylation of Oxindoles with Alcohols. ChemSusChem 2019, 12, 2345-2349; DOI:10.1002/cssc.201900799.
4. Wu, Q.; Pan, L.; Du, G.; Zhang, C.; Wang, D. Preparation of pyridyltriazole ruthenium complexes as effective catalysts for the selective alkylation and one-pot C–H hydroxylation of 2-oxindole with alcohols and mechanism exploration. Chem. Front. 2018, 5, 2668-2675; DOI:10.1039/c8qo00725j.
5. Grigg, R.; Whitney, S.; Sridharan, V.; Keep, A.; Derrick, A. Iridium catalysed C-3 alkylation of oxindole with alcohols under solvent free thermal or microwave conditions. Tetrahedron 2009, 65, 4375-4383; DOI:10.1016/j.tet.2009.03.065.
6. Ghosh, A.; Bera, A.; Banerjee, D. Nickel Catalyzed Alkylation of Oxindoles with Alkyl Alcohols. ChemCatChem 2023, 15, e202201433; DOI:10.1002/cctc.202201433.
7. Yu, K.; Chen, Q.; Liu, W. Iron-catalysed quinoline synthesis via acceptorless dehydrogenative coupling. Chem. Front. 2022, 9, 6573-6578; DOI:10.1039/d2qo01386j.
8. Hao, Z.; Zhou, X.; Ma, Z.; Zhang, C.; Han, Z.; Lin, J.; Lu, G.L. Dehydrogenative Synthesis of Quinolines and Quinazolines via Ligand-Free Cobalt-Catalyzed Cyclization of 2-Aminoaryl Alcohols with Ketones or Nitriles. J. Org. Chem. 2022, 87, 12596-12607; DOI:10.1021/acs.joc.2c00734.
9. Jana, A.; Kumar, A.; Maji, B. Manganese catalyzed C-alkylation of methyl N-heteroarenes with primary alcohols. Chem. Commun. 2021, 57, 3026-3029; DOI:10.1039/d1cc00181g.

For new synthetic compounds 3h, the HRMS were added. As follows:

3-(4-(Tert-butyl)benzyl)indolin-2-one (3h).

yellow solid; ¹H NMR (400 MHz, CDCl₃) δ 9.36 (s, 1H), 7.31 (d, J = 8.3 Hz, 2H), 7.15 (t, J = 8.0 Hz, 3H), 6.92 (t, J = 7.7 Hz, 2H), 6.75 (d, J = 7.5 Hz, 1H), 3.76 (dd, J = 9.7, 4.3 Hz, 1H), 3.50 (dd, J = 13.8, 4.3 Hz, 1H), 2.85 (dd, J = 13.8, 9.6 Hz, 1H), 1.30 (s, 9H). ¹³C NMR (101 MHz, CDCl₃) δ 180.45, 149.65, 141.71, 135.01, 129.43, 129.17, 128.05, 125.40, 124.95, 122.13, 110.05, 47.80, 36.33, 34.55, 31.49. HRMS Calculated for C₁₉H₂₂NO [M+H]⁺ 280.1701, found 280.1702.

 

Response to Reviewer 2

We are very grateful for the recommendations of Reviewer 2 (The manuscript describes the preparation, characterization of polymer supported heterogeneous Ni-CIA catalyst and its application in the synthesis of oxindoles and quinolines via borrowing hydrogen reactions. Besides enabling the synthesis of the two kinds of products with broad scope, the catalyst also displays evidently higher catalytic activity than simple Ni-salts, and advantage in recovery. The work is recommended for publication in Catalysts after revision by addressing a few issues.)

1. For the 1st question of “In the introduction, the authors have discussed the biologically active oxindoles. As the other class of products reported in the manuscript, the quinolines should also be discussed in the area of biological & pharmaceutical functions. For some examples: Org. Biomol. Chem. 2022, 20, 4385; Chin. J. Org. Chem. 2022, 42, 2947; Catalysts 2022, 12, 1468; Curr. Med. Chem. 2017, 24, 2241.”.

Response: According to the suggestion of Reviewer 2, All the four references were added in ref 5-8. As follows:

5. Huang, L.; Yang, L.; Wan, J.P.; Zhou, L.; Liu, Y.; Hao, G. Metal-free three-component assemblies of anilines, alpha-keto acids and alkyl lactates for quinoline synthesis and their anti-inflammatory activity. Biomol. Chem. 2022, 20, 4385-4390; DOI:10.1039/d2ob00661h.
6. Liu, H.; Zeng, X.-Q.; Zuo, H.-W.; Zhang, N.; Huang, Z.-Y. Design, Synthesis and Seed Germination Inhibition Activity of Quinoline-6-sulfonamide Compounds. J. Org. Chem. 2022, 42, 2947-2953; DOI:10.6023/cjoc202206040.
7. Moutaouakil, M.; Tighadouini, S.; M. Almarhoon, Z.; I. Al-Zaben, M.; Ben Bacha, A.; H. Masand, V.; Jamaleddine, J.; Saddik, R. Quinoline Derivatives with Different Functional Groups: Evaluation of Their Catecholase Activity. Catalysts 2022, 12, 1468; DOI:10.3390/catal12111468.
8. Hu, C.; Lu, L.; Wan, J.P.; Wen, C. The Pharmacological Mechanisms and Therapeutic Activities of Hydroxychloroquine in Rheumatic and Related Diseases. Med. Chem. 2017, 24, 2241-2249; DOI:10.2174/0929867324666170316115938.
9. For the 2nd question of “The experimental for the recovery of Ni-CIA catalyst should be provided in the revised manuscript.”.

Response: According to the suggestions of Reviewer 2. We provided that the characterization of the spent catalyst by SEM in the revised manuscript. It could be seen from the figure that the morphology of the catalyst Ni-CIA had no obvious change and it still had a a slice layer stacked combination structure.

One sentence was added to explain this. As follows: (Page 14, lines 276-280)

After recycling experiments, the Ni-CIA catalyst was collected and characterized by scanning electron microscope (SEM) again after washed three times with methanol, deionized water, ethanol, and dried at 80 ^oC (Figure S1). From the figure, no significant change in the morphology of the catalyst Ni-CIA is seen, retaining its slice layer stacked combination structure.

 

Figure S1. (a) and (b) SEM image of Ni-CIA after being recycled five times.

3. For the 3rd question of “Table 2, the reaction using simple alkyl alcohol such as propanol should be conducted and discussed.”.

Response: According to the suggestions of Reviewer 2. We try to expand the alkylation of aliphatic alcohols and alicyclic alcohol with 2-oxindole. The results showed that the reaction could take place smoothly and the corresponding desired product could be obtained in moderate to good yields.

Two sentences were added to explain this. As follows: (Page 6, lines 149-153)

The scope was further extended to linear aliphatic secondary alcohols. Interestingly, aliphatic alcohols were also effective for the alkylation of 2-oxindole to offer the corresponding products 3q-3s in moderate yields. Meanwhile, alicyclic alcohol (cyclopropane methanol 2t) was also effective in yielding the corresponding products 3-(cyclopropyl methyl)indolin-2-one 3t in good yields.

4. For the 4th question of “Scheme 4, the mechanism for the reactions toward quinoline synthesis should also be included.”.

Response: As suggested by Reviewer 2, We have added a series of control experiments to the synthesis of quinoline derivatives and proposed possible reaction mechanisms in the revised manuscript, As follows: (Page 10, lines 218-235)

Subsequently, to understand the mechanism of 6a formation, a series of control experiments were performed (Scheme 4). Initially, In the presence of BTH and TEMPO, this transformation proceeded well, and the yield of 6a was only slightly decreased. This rule out the involvement of an organic radical intermediate during this reaction, as it is widely accepted that the capture of key intermediate is an efficient and reliable way to explain what happened in this reaction process. The reaction of only o-aminobenzyl alcohol 4a give 2-aminobenzaldehyde 4a’ in 58% isolated yield under the standard conditions (i). Reaction of 2-aminobenzaldehyde 4a’ and acetophenone 5a afforded the 2-phenylquinoline 6a in 94% yield in absence of catlayst Ni-CIA, implying that the carbonyl compound (2-aminobenzaldehyde 4a’) is the intermediate and Cs₂CO₃ played a significant role for deprotonation of alcohols and condensation (ii). Notably, the formation of 2-phenylquinoline 6a was not observed from the coupling of o-aminobenzyl alcohol 4a with acetophenone 5a in the absence of catalyst (iii). The above control experiment results together confirmed that the catalyst Ni-CIA facilitated the dehydrogenation of the o-aminobenzyl alcohol 4a, and that 2-aminobenzaldehyde 4a’ was the intermediate in this process.

Scheme 4. Mechanism exploration experiments for the synthesis of quinolines.

(Page 12, lines 247-259):

Similarly, A plausible mechanism for the Ni-catalyzed synthesis of quinoline derivatives via the dehydrogenative coupling of o-aminobenzyl alcohol 4a with acetophenone 5a is shown in Scheme 6. Firstly, the deprotonation of 4a assisted by the Cs₂CO₃ produces the active species C, which then participate in this catalytic cycle. Next , C reacted with Ni-CIA to afford the alkoxy intermediate D. The intermediate D undergoes β-hydride elimination of alkoxide to produce the dehydrogenated product 2-aminobenzaldehyde 4a’ with the formation of [Ni-H] species. Subsequently, 2-aminobenzaldehyde 4a’ undergoes base-catalyzed cross-aldol condensation reaction with acetophenone 5a to form an α, β -unsaturated ketone. Finally, the α, β -unsaturated ketone reacts via intramolecular cyclization to give the product 6a.

Scheme 6. Proposed possible reaction mechanism for the synthesis of quinolines.

5. For the 5th question of “Closely related works on dehydrogenative annulation for quinoline synthesis should be cited: Green Chem. 2020, 22, 3074; Green Synth. Catal. 2022, 3, 95-101 etc.”.

Response: According to the suggestion of Reviewer 2, All the two references were added in ref 68-69. As follows:

68. Yang, L.; Wan, J.-P. Ethyl lactate-involved three-component dehydrogenative reactions: biomass feedstock in diversity-oriented quinoline synthesis. Green Chem. 2020, 22, 3074-3078; DOI:10.1039/d0gc00738b.
69. Li, R.; Jiang, S.; Zheng, H.; Lei, H.; Huang, Z.; Chen, S.; Deng, G.-J. Iron-catalyzed indolo[2,3-c]quinoline synthesis from nitroarenes and benzylic alcohols/aldehydes promoted by elemental sulfur. Green Synth. Catal. 2022, 3, 95-101; DOI:10.1016/j.gresc.2021.11.006.

 

Response to Reviewer 3

We are very grateful for the recommendations of Reviewer 3.

1. For the 1st question of “All abbreviations such as Ni-CIA and TLC must be given at their first uses.”.

Response: As suggested by Reviewer 3, We have checked the manuscript and added the full name before the abbreviation at their first uses.

List of abbreviations as follows:

Fourier transform infrared (FT-IR); powder X-ray diffraction (XRD); scanning electron microscope (SEM); X-ray photoelectron spectrometry (XPS); energy-dispersive X-ray spectroscopy (EDS); Thermal gravimetric analysis (TGA); Coordination polymers (CPs); Ni-CIA (Ni-indolyl dicarboxylic acid coordination polymer); H₂CIA (indolyl dicarboxylic acid ligand); N,N-dimethylformamide (DMF); thin layer chromatography (TLC).

2. For the 2nd question of “Authors need to check formats of the manuscript, including line spacing, and revise accordingly.”.

Response: According to the suggestion of Reviewer 3. We have checked the format of the manuscript and made corresponding modifications.

3. For the 3rd question of “Section 3 (Materials and Methods) must be switched with Section 2.”.

Response: We thank Reviewer 3 for this suggestion, Section 3 (Materials and Methods) has been switched with Section 2.

4. For the 4th question of “Countries of manufacturer for chemicals and equipment must be provided.”.

Response: According to the suggestion of Reviewer 3, we added the explanation of reagents and solvents. As follows:

FT-IR spectra (Thermo Fisher Co, USA).

SEM image and EDS spectra (Hitachi, Japan).

TG analysis was carried out using a STA409 (Mettler-Toli, Switzerland).

XRD patterns were collected on a Bruker D8 (Germany).

XPS (ESCALAB 250Xi, Thermo Fisher Co, USA).

¹H NMR and ¹³C NMR spectra were obtained on Bruker Advance III HD (Switzerland).

The chemicals were used as received: methyl indole-5-carboxylate (>98%, Adamas), methyl 2-bromoacetate (>98%, Adamas), anhydrous potassium carbonate (K₂CO₃, >99%, Sinopharm), anhydrous magnesium sulfate (MgSO₄, >99%, Sinopharm), acetonitrile (MeCN, 99.9%, Sigma), LiOH·H₂O (>95%, Sinopharm), Tetrahydrofuran (THF, 99.9%, Sigma), NiCl₂^.6H₂O (Adamas), N,N-dimethylformamide (DMF, 99.9%, Sigma), ethanol (99%, Sigma), KOtBu (>98%, Sinopharm), 2-oxindole derivative (>98%, Adamas), benzyl alcohol derivatives (>99%, Adamas), o-aminobenzyl alcohol (99%, Sigma), acetophenone derivatives (>99%, Adamas), Unless otherwise noted, all commercial reagents and solvents were obtained from the commercial provider and used without further purification.

5. For the 5th question of “Section 4 must be moved to supplementary or authors need to find better way to represent the information.”.

Response: According to the suggestions, Section 4 were transferred into the supporting information part from manuscript (main text).

6. For the 6th question of “Conclusion must be improved. Main findings as well as their implications should be included in the conclusion.”.

Response: We thank Reviewer 3 again for this, we have made modifications to the conclusion section of the manuscript by incorporating the main conclusions of the experiment and relevant content on its impact. As follows:

In summary, we herein report a simple, effective, and reusable heterogeneous coordination polymer Ni-CIA catalyst for promoting the synthesis of oxindole and quinoline derivatives through the borrowing hydrogen strategy. The slice layer stacked combination structure of the catalyst can effectively promote the ion diffusion and accelerate catalytic mass transfer during the catalytic reaction. Moreover, various primary alcohol and acetophenone substrates were tested under optimized reaction conditions to form the desired compounds in moderate to excellent yields. After that, the mechanism explorations including control experiments were conducted to clarify the effect of different substituents and cooperative effects were conducted to clarify these transformations. The above experiment results confirmed that catalysis with Ni-CIA facilitates the dehydrogenation of the benzyl alcohol 2a and o-aminobenzyl alcohol 4a, revealing that the reaction followed hydrogen-borrowing mechanism, thus proposed the possible reaction mechanism for the two types of reactions. Finally, the recycled experiments showed that the Ni-CIA catalyst had fine stability. In particular, it was showed that no significant reduction in activity was observed for Ni-CIA after five runs and no significant changes in its surface morphology of the catalyst. This catalytic system is shown as a much greener way for the synthesis of oxindole and quinoline derivatives, in accordance with the principles of sustainable development and atom economy, making it highly promising for organic catalysis.

7. For the 7th question of “English must be carefully checked and revised. Some sentences were hard to understand and awkward.”.

Response: According to the suggestion of Reviewer 3, we checked this manuscript carefully and the errors were corrected, as follows:

(1) (Page 1, line 13) “have” was corrected as “has”.

(2) (Page 1, line 17) “were revealed to have” was corrected as “reveals”.

(3) (Page 1, line 21) “the” was added.

(4) (Page 1, line 31) “with” was added.

(5) (Page 1, line 38) “which” was deleted.

(6) (Page 1, line 41) “a” was added.

(7) (Page 1, line 45) “and” was corrected as “which”.

(8) (Page 1, line 55) “separating” was corrected as “separation”.

(9) (Page 1, line 56) “several” was corrected as “a number of”.

(10) (Page 1, line 56) “with” was added.

(11) (Page 1, line 57) “could be” was added.

(12) (Page 4, line 134) “carefully” was deleted.

(13) (Page 4, line 141) “and” was deleted.

(14) (Page 5, line 148) “that” was added.

(15) (Page 5, line 149) “the” was deleted.

(16) (Page 5, line 152) “are observed” was added.

(17) (Page 5, line 158) “was” was corrected as “has a”.

(18) (Page 5, line 160) “reaction” was corrected as “process”.

(19) (Page 6, line 182) “analyze” was corrected as “analyzed”.

(20) (Page 6, line 185) “to” was added.

(21) (Page 6, line 185) “disintegrating” was corrected as “disintegrate”.

(22) (Page 7, line 198) “the” was added.

(23) (Page 7, line 198) “afford” was corrected as “afforded”.

(24) (Page 7, line 201) “and” was added.

(25) (Page 8, line 217) “groups” was deleted.

(26) (Page 8, line 223) “are” was added.

(27) (Page 10, line 239) “the” was deleted.

(28) (Page 10, line 240) “are” was corrected as “is”.

(29) (Page 10, line 244) “a” was added.

(30) (Page 11, line 257) “yield” was corrected as “yields”.

(31) (Page 12, line 270) “the” was added.

(32) (Page 12, line 270) “has” was deleted.

(33) (Page 12, line 271) “this” was corrected as “the”.

(34) (Page 13, line 278) “group” was deleted.

(35) (Page 13, line 279) “group” was corrected as “groups”.

(36) (Page 13, line 281) “found to be” was added.

(37) (Page 13, line 281) “the” was added.

(38) (Page 13, line 283) “group” was added”.

(39) (Page 14, line 297) “intermediate” was corrected as “intermediates”.

(40) (Page 14, line 297) “to form” was corrected as “affords”.

(41) (Page 15, line 325) “undergo” was corrected as “undergoes”.

(42) (Page 15, line 326) “and” was corrected as “which”.

(43) (Page 15, line 327) “participate” was corrected as “participates”.

(44) (Page 15, line 328) “and” was corrected as “which”.

(45) (Page 15, line 328) “formation of” was deleted.

(46) (Page 15, line 352) “following” was corrected as “followed”.

(47) (Page 15, line 352) “and” was added”.

(48) (Page 15, line 353) “respectively” was added”.

(49) (Page 15, line 352) “drying” was corrected as “dried”.

(50) (Page 15, line 355) “the” was added”.

(51) (Page 15, line 356) “showed” was corrected as “shown”.

 

Response to Reviewer 4

We are very grateful for the recommendations of Reviewer 4.( The authors further expanded this synthetic method to the construction of quinoline motif. The investigation was carefully achieved, and the paper is well written. The mechanism is suitably proposed, and mechanistic studies supported this hypothesis. I would recommend publication of this manuscript in catalysts.

1. For the 1st question of “Page 2, line 55: The word “Indolyl” should be corrected to “indolyl”.”.

Response: We thank Reviewer 4 very much for helping us correct the mistakes and errors, (Page 2, line 55) “Indolyl” was corrected as “indolyl”

2. For the 2nd question of “Page 4, line 118: The word “87%” should be corrected to “84%” according to the result of entry 5.”.

Response: We thank Reviewer 4 again for this, (Page 4, line 118) “87%” was corrected as “84%”.

3. For the 3rd question of “Page 5, Table 1: The authors should write the reaction temperature. In entry 11, the reaction temperature is unclear (111 ^oC: boiling point of toluene ?).”.

Response: We thank Reviewer 4 very much for this comment. we have revised the reaction temperature in the manuscript (the reaction temperature is 120 ºC).

4. For the 4th question of “Page 6, line 150: The word “moderate” should be corrected to “good (or excellent).”.

Response: We thank Reviewer 4 again for helping us correct the mistakes and errors, (Page 6, line 150) “moderate” was corrected as “good”.

5. For the 5th question of “Page 6, line 159: Reference about the synthesis of quinoline derivatives should be cited (H. Hikawa and I. Azumaya et al. Asian J. Org. Chem. 2022, e202200510).”.

Response: According to the suggestion of Reviewer 4, the reference was added in ref 24. As follows:

24. Nakayama, T.; Harada, S.; Kikkawa, S.; Hikawa, H.; Azumaya, I. Palladium‐Catalyzed Dehydrogenative Synthesis of Imidazoquinolines in Water. Asian J. Org. Chem. 2022, 11, e202200510; DOI:10.1002/ajoc.202200510.

 

 

 

 

If you have any questions concerning the manuscript, please feel free to contact me.

Thank you very much for your consideration.

With best regards

 

Prof. Dawei Wang

Jiangnan University

1800 Lihu Road,

Wuxi, 214122, P. R. China

Email: [email protected]

 

Author Response File: Author Response.doc

Reviewer 4 Report

This paper describes a preparation of a novel Ni-containing coordination polymer and its application for the synthesis of oxindoles and quinolines by borrowing hydrogen methodology. The new catalytic material was fully characterized by FT-IR, XRD, SEM, XPS, EDS and TGA. The catalytic reactions of 2-oxindole (1a) with series of benzylic alcohols (2) were proceeded smoothly to furnish the corresponding oxindole products in good to excellent yields. These catalysts could be easily recovered and reused without loss of its catalytic activity. The authors further expanded this synthetic method to the construction of quinoline motif. The investigation was carefully achieved, and the paper is well written. The mechanism is suitably proposed, and mechanistic studies supported this hypothesis. I would recommend publication of this manuscript in catalysts.

 

The following points should be considered before the publication.

Page 2, line 55: The word “Indolyl” should be corrected to “indolyl”.

Page 4, line 118: The word “87%” should be corrected to “84%” according to the result of entry 5.

Page 5, Table 1: The authors should write the reaction temperature. In entry 11, the reaction temperature is unclear (111 oC: boiling point of toluene ?).

Page 6, line 150: The word “moderate” should be corrected to “good (or excellent)”.

Page 6, line 159: Reference about the synthesis of quinoline derivatives should be cited (H. Hikawa and I. Azumaya et al. Asian J. Org. Chem. 2022, e202200510).

Author Response

Dear Editor and Reviewers,

Thank you very much for giving us the opportunity to revise the manuscript (catalysts-2514205). Enclosed please find our revised manuscript “Recyclable Ni-containing coordination polymer as efficient catalysts for the synthesis of oxindole and quinoline derivatives through borrowing hydrogen strategy” by Jiahao Li ^†, Jiajie Tang ^†, Likui Wang, Dawei Wang*, and Zheng-Chao Duan*.

We would like to express our heartfelt thanks for Editorial Office and four Reviewers. We have revised the manuscript according to the comments and suggestions, these questions were answered one by one.

 

Response to Reviewer 1

We are very grateful for the comments of Reviewer 1 (Very well written manuscript. Only few things need to be revised.)

1. For the 1st question of “Page 11; 3.2 should be procedure for alkylation of 2-oxindole. Suggestion is removing topic 3.2 and move lines 267-284 to line after 242.”.

Response: According to the suggestion of Reviewer 1, topic 3.2 has been moved to line after 242.

2. For the 2nd question of “CHLOROFORM-D should be CDCl₃ and DMSO-D should be DMSO-d₆.”.

Response: We thank Reviewer 1 for this suggestion, all “CHLOROFORM-D and DMSO-D” in the manuscript was corrected as “CDCl₃ and DMSO-d₆^” , respectively.

3. For the 3rd question of “For known compounds (H₂CIA, compounds 3 and 6), references should be cited. HRMS data are required for new synthetic compounds (compounds 3 and 6).”

Response: According to the suggestion of Reviewer 1, All the references (For known compounds) were added in the supporting information part. As follows:

1. Hu, X.; Zhu, H.; Sang, X.; Wang, D. Design and Synthesis of Zirconium-Containing Coordination Polymer Based on Unsymmetric Indolyl Dicarboxylic Acid and Catalytic Application on Borrowing Hydrogen Reaction. Synth. Catal. 2018, 360, 4293-4300; DOI:10.1002/adsc.201800875.
2. Saini, P.; Dolui, P.; Nair, A.; Verma, A.; Elias, A.J. A Bench-stable 8-Aminoquinoline Derived Phosphine-free Manganese (I)-Catalyst for Environmentally Benign C(alpha)-Alkylation of Oxindoles with Secondary and Primary Alcohols. Asian J. 2023, 18, e202201148; DOI:10.1002/asia.202201148.
3. Dambatta, M.B.; Polidano, K.; Northey, A.D.; Williams, J.M.J.; Morrill, L.C. Iron-Catalyzed Borrowing Hydrogen C-Alkylation of Oxindoles with Alcohols. ChemSusChem 2019, 12, 2345-2349; DOI:10.1002/cssc.201900799.
4. Wu, Q.; Pan, L.; Du, G.; Zhang, C.; Wang, D. Preparation of pyridyltriazole ruthenium complexes as effective catalysts for the selective alkylation and one-pot C–H hydroxylation of 2-oxindole with alcohols and mechanism exploration. Chem. Front. 2018, 5, 2668-2675; DOI:10.1039/c8qo00725j.
5. Grigg, R.; Whitney, S.; Sridharan, V.; Keep, A.; Derrick, A. Iridium catalysed C-3 alkylation of oxindole with alcohols under solvent free thermal or microwave conditions. Tetrahedron 2009, 65, 4375-4383; DOI:10.1016/j.tet.2009.03.065.
6. Ghosh, A.; Bera, A.; Banerjee, D. Nickel Catalyzed Alkylation of Oxindoles with Alkyl Alcohols. ChemCatChem 2023, 15, e202201433; DOI:10.1002/cctc.202201433.
7. Yu, K.; Chen, Q.; Liu, W. Iron-catalysed quinoline synthesis via acceptorless dehydrogenative coupling. Chem. Front. 2022, 9, 6573-6578; DOI:10.1039/d2qo01386j.
8. Hao, Z.; Zhou, X.; Ma, Z.; Zhang, C.; Han, Z.; Lin, J.; Lu, G.L. Dehydrogenative Synthesis of Quinolines and Quinazolines via Ligand-Free Cobalt-Catalyzed Cyclization of 2-Aminoaryl Alcohols with Ketones or Nitriles. J. Org. Chem. 2022, 87, 12596-12607; DOI:10.1021/acs.joc.2c00734.
9. Jana, A.; Kumar, A.; Maji, B. Manganese catalyzed C-alkylation of methyl N-heteroarenes with primary alcohols. Chem. Commun. 2021, 57, 3026-3029; DOI:10.1039/d1cc00181g.

For new synthetic compounds 3h, the HRMS were added. As follows:

3-(4-(Tert-butyl)benzyl)indolin-2-one (3h).

yellow solid; ¹H NMR (400 MHz, CDCl₃) δ 9.36 (s, 1H), 7.31 (d, J = 8.3 Hz, 2H), 7.15 (t, J = 8.0 Hz, 3H), 6.92 (t, J = 7.7 Hz, 2H), 6.75 (d, J = 7.5 Hz, 1H), 3.76 (dd, J = 9.7, 4.3 Hz, 1H), 3.50 (dd, J = 13.8, 4.3 Hz, 1H), 2.85 (dd, J = 13.8, 9.6 Hz, 1H), 1.30 (s, 9H). ¹³C NMR (101 MHz, CDCl₃) δ 180.45, 149.65, 141.71, 135.01, 129.43, 129.17, 128.05, 125.40, 124.95, 122.13, 110.05, 47.80, 36.33, 34.55, 31.49. HRMS Calculated for C₁₉H₂₂NO [M+H]⁺ 280.1701, found 280.1702.

 

Response to Reviewer 2

We are very grateful for the recommendations of Reviewer 2 (The manuscript describes the preparation, characterization of polymer supported heterogeneous Ni-CIA catalyst and its application in the synthesis of oxindoles and quinolines via borrowing hydrogen reactions. Besides enabling the synthesis of the two kinds of products with broad scope, the catalyst also displays evidently higher catalytic activity than simple Ni-salts, and advantage in recovery. The work is recommended for publication in Catalysts after revision by addressing a few issues.)

1. For the 1st question of “In the introduction, the authors have discussed the biologically active oxindoles. As the other class of products reported in the manuscript, the quinolines should also be discussed in the area of biological & pharmaceutical functions. For some examples: Org. Biomol. Chem. 2022, 20, 4385; Chin. J. Org. Chem. 2022, 42, 2947; Catalysts 2022, 12, 1468; Curr. Med. Chem. 2017, 24, 2241.”.

Response: According to the suggestion of Reviewer 2, All the four references were added in ref 5-8. As follows:

5. Huang, L.; Yang, L.; Wan, J.P.; Zhou, L.; Liu, Y.; Hao, G. Metal-free three-component assemblies of anilines, alpha-keto acids and alkyl lactates for quinoline synthesis and their anti-inflammatory activity. Biomol. Chem. 2022, 20, 4385-4390; DOI:10.1039/d2ob00661h.
6. Liu, H.; Zeng, X.-Q.; Zuo, H.-W.; Zhang, N.; Huang, Z.-Y. Design, Synthesis and Seed Germination Inhibition Activity of Quinoline-6-sulfonamide Compounds. J. Org. Chem. 2022, 42, 2947-2953; DOI:10.6023/cjoc202206040.
7. Moutaouakil, M.; Tighadouini, S.; M. Almarhoon, Z.; I. Al-Zaben, M.; Ben Bacha, A.; H. Masand, V.; Jamaleddine, J.; Saddik, R. Quinoline Derivatives with Different Functional Groups: Evaluation of Their Catecholase Activity. Catalysts 2022, 12, 1468; DOI:10.3390/catal12111468.
8. Hu, C.; Lu, L.; Wan, J.P.; Wen, C. The Pharmacological Mechanisms and Therapeutic Activities of Hydroxychloroquine in Rheumatic and Related Diseases. Med. Chem. 2017, 24, 2241-2249; DOI:10.2174/0929867324666170316115938.
9. For the 2nd question of “The experimental for the recovery of Ni-CIA catalyst should be provided in the revised manuscript.”.

Response: According to the suggestions of Reviewer 2. We provided that the characterization of the spent catalyst by SEM in the revised manuscript. It could be seen from the figure that the morphology of the catalyst Ni-CIA had no obvious change and it still had a a slice layer stacked combination structure.

One sentence was added to explain this. As follows: (Page 14, lines 276-280)

After recycling experiments, the Ni-CIA catalyst was collected and characterized by scanning electron microscope (SEM) again after washed three times with methanol, deionized water, ethanol, and dried at 80 ^oC (Figure S1). From the figure, no significant change in the morphology of the catalyst Ni-CIA is seen, retaining its slice layer stacked combination structure.

 

Figure S1. (a) and (b) SEM image of Ni-CIA after being recycled five times.

3. For the 3rd question of “Table 2, the reaction using simple alkyl alcohol such as propanol should be conducted and discussed.”.

Response: According to the suggestions of Reviewer 2. We try to expand the alkylation of aliphatic alcohols and alicyclic alcohol with 2-oxindole. The results showed that the reaction could take place smoothly and the corresponding desired product could be obtained in moderate to good yields.

Two sentences were added to explain this. As follows: (Page 6, lines 149-153)

The scope was further extended to linear aliphatic secondary alcohols. Interestingly, aliphatic alcohols were also effective for the alkylation of 2-oxindole to offer the corresponding products 3q-3s in moderate yields. Meanwhile, alicyclic alcohol (cyclopropane methanol 2t) was also effective in yielding the corresponding products 3-(cyclopropyl methyl)indolin-2-one 3t in good yields.

4. For the 4th question of “Scheme 4, the mechanism for the reactions toward quinoline synthesis should also be included.”.

Response: As suggested by Reviewer 2, We have added a series of control experiments to the synthesis of quinoline derivatives and proposed possible reaction mechanisms in the revised manuscript, As follows: (Page 10, lines 218-235)

Subsequently, to understand the mechanism of 6a formation, a series of control experiments were performed (Scheme 4). Initially, In the presence of BTH and TEMPO, this transformation proceeded well, and the yield of 6a was only slightly decreased. This rule out the involvement of an organic radical intermediate during this reaction, as it is widely accepted that the capture of key intermediate is an efficient and reliable way to explain what happened in this reaction process. The reaction of only o-aminobenzyl alcohol 4a give 2-aminobenzaldehyde 4a’ in 58% isolated yield under the standard conditions (i). Reaction of 2-aminobenzaldehyde 4a’ and acetophenone 5a afforded the 2-phenylquinoline 6a in 94% yield in absence of catlayst Ni-CIA, implying that the carbonyl compound (2-aminobenzaldehyde 4a’) is the intermediate and Cs₂CO₃ played a significant role for deprotonation of alcohols and condensation (ii). Notably, the formation of 2-phenylquinoline 6a was not observed from the coupling of o-aminobenzyl alcohol 4a with acetophenone 5a in the absence of catalyst (iii). The above control experiment results together confirmed that the catalyst Ni-CIA facilitated the dehydrogenation of the o-aminobenzyl alcohol 4a, and that 2-aminobenzaldehyde 4a’ was the intermediate in this process.

Scheme 4. Mechanism exploration experiments for the synthesis of quinolines.

(Page 12, lines 247-259):

Similarly, A plausible mechanism for the Ni-catalyzed synthesis of quinoline derivatives via the dehydrogenative coupling of o-aminobenzyl alcohol 4a with acetophenone 5a is shown in Scheme 6. Firstly, the deprotonation of 4a assisted by the Cs₂CO₃ produces the active species C, which then participate in this catalytic cycle. Next , C reacted with Ni-CIA to afford the alkoxy intermediate D. The intermediate D undergoes β-hydride elimination of alkoxide to produce the dehydrogenated product 2-aminobenzaldehyde 4a’ with the formation of [Ni-H] species. Subsequently, 2-aminobenzaldehyde 4a’ undergoes base-catalyzed cross-aldol condensation reaction with acetophenone 5a to form an α, β -unsaturated ketone. Finally, the α, β -unsaturated ketone reacts via intramolecular cyclization to give the product 6a.

Scheme 6. Proposed possible reaction mechanism for the synthesis of quinolines.

5. For the 5th question of “Closely related works on dehydrogenative annulation for quinoline synthesis should be cited: Green Chem. 2020, 22, 3074; Green Synth. Catal. 2022, 3, 95-101 etc.”.

Response: According to the suggestion of Reviewer 2, All the two references were added in ref 68-69. As follows:

68. Yang, L.; Wan, J.-P. Ethyl lactate-involved three-component dehydrogenative reactions: biomass feedstock in diversity-oriented quinoline synthesis. Green Chem. 2020, 22, 3074-3078; DOI:10.1039/d0gc00738b.
69. Li, R.; Jiang, S.; Zheng, H.; Lei, H.; Huang, Z.; Chen, S.; Deng, G.-J. Iron-catalyzed indolo[2,3-c]quinoline synthesis from nitroarenes and benzylic alcohols/aldehydes promoted by elemental sulfur. Green Synth. Catal. 2022, 3, 95-101; DOI:10.1016/j.gresc.2021.11.006.

 

Response to Reviewer 3

We are very grateful for the recommendations of Reviewer 3.

1. For the 1st question of “All abbreviations such as Ni-CIA and TLC must be given at their first uses.”.

Response: As suggested by Reviewer 3, We have checked the manuscript and added the full name before the abbreviation at their first uses.

List of abbreviations as follows:

Fourier transform infrared (FT-IR); powder X-ray diffraction (XRD); scanning electron microscope (SEM); X-ray photoelectron spectrometry (XPS); energy-dispersive X-ray spectroscopy (EDS); Thermal gravimetric analysis (TGA); Coordination polymers (CPs); Ni-CIA (Ni-indolyl dicarboxylic acid coordination polymer); H₂CIA (indolyl dicarboxylic acid ligand); N,N-dimethylformamide (DMF); thin layer chromatography (TLC).

2. For the 2nd question of “Authors need to check formats of the manuscript, including line spacing, and revise accordingly.”.

Response: According to the suggestion of Reviewer 3. We have checked the format of the manuscript and made corresponding modifications.

3. For the 3rd question of “Section 3 (Materials and Methods) must be switched with Section 2.”.

Response: We thank Reviewer 3 for this suggestion, Section 3 (Materials and Methods) has been switched with Section 2.

4. For the 4th question of “Countries of manufacturer for chemicals and equipment must be provided.”.

Response: According to the suggestion of Reviewer 3, we added the explanation of reagents and solvents. As follows:

FT-IR spectra (Thermo Fisher Co, USA).

SEM image and EDS spectra (Hitachi, Japan).

TG analysis was carried out using a STA409 (Mettler-Toli, Switzerland).

XRD patterns were collected on a Bruker D8 (Germany).

XPS (ESCALAB 250Xi, Thermo Fisher Co, USA).

¹H NMR and ¹³C NMR spectra were obtained on Bruker Advance III HD (Switzerland).

The chemicals were used as received: methyl indole-5-carboxylate (>98%, Adamas), methyl 2-bromoacetate (>98%, Adamas), anhydrous potassium carbonate (K₂CO₃, >99%, Sinopharm), anhydrous magnesium sulfate (MgSO₄, >99%, Sinopharm), acetonitrile (MeCN, 99.9%, Sigma), LiOH·H₂O (>95%, Sinopharm), Tetrahydrofuran (THF, 99.9%, Sigma), NiCl₂^.6H₂O (Adamas), N,N-dimethylformamide (DMF, 99.9%, Sigma), ethanol (99%, Sigma), KOtBu (>98%, Sinopharm), 2-oxindole derivative (>98%, Adamas), benzyl alcohol derivatives (>99%, Adamas), o-aminobenzyl alcohol (99%, Sigma), acetophenone derivatives (>99%, Adamas), Unless otherwise noted, all commercial reagents and solvents were obtained from the commercial provider and used without further purification.

5. For the 5th question of “Section 4 must be moved to supplementary or authors need to find better way to represent the information.”.

Response: According to the suggestions, Section 4 were transferred into the supporting information part from manuscript (main text).

6. For the 6th question of “Conclusion must be improved. Main findings as well as their implications should be included in the conclusion.”.

Response: We thank Reviewer 3 again for this, we have made modifications to the conclusion section of the manuscript by incorporating the main conclusions of the experiment and relevant content on its impact. As follows:

In summary, we herein report a simple, effective, and reusable heterogeneous coordination polymer Ni-CIA catalyst for promoting the synthesis of oxindole and quinoline derivatives through the borrowing hydrogen strategy. The slice layer stacked combination structure of the catalyst can effectively promote the ion diffusion and accelerate catalytic mass transfer during the catalytic reaction. Moreover, various primary alcohol and acetophenone substrates were tested under optimized reaction conditions to form the desired compounds in moderate to excellent yields. After that, the mechanism explorations including control experiments were conducted to clarify the effect of different substituents and cooperative effects were conducted to clarify these transformations. The above experiment results confirmed that catalysis with Ni-CIA facilitates the dehydrogenation of the benzyl alcohol 2a and o-aminobenzyl alcohol 4a, revealing that the reaction followed hydrogen-borrowing mechanism, thus proposed the possible reaction mechanism for the two types of reactions. Finally, the recycled experiments showed that the Ni-CIA catalyst had fine stability. In particular, it was showed that no significant reduction in activity was observed for Ni-CIA after five runs and no significant changes in its surface morphology of the catalyst. This catalytic system is shown as a much greener way for the synthesis of oxindole and quinoline derivatives, in accordance with the principles of sustainable development and atom economy, making it highly promising for organic catalysis.

7. For the 7th question of “English must be carefully checked and revised. Some sentences were hard to understand and awkward.”.

Response: According to the suggestion of Reviewer 3, we checked this manuscript carefully and the errors were corrected, as follows:

(1) (Page 1, line 13) “have” was corrected as “has”.

(2) (Page 1, line 17) “were revealed to have” was corrected as “reveals”.

(3) (Page 1, line 21) “the” was added.

(4) (Page 1, line 31) “with” was added.

(5) (Page 1, line 38) “which” was deleted.

(6) (Page 1, line 41) “a” was added.

(7) (Page 1, line 45) “and” was corrected as “which”.

(8) (Page 1, line 55) “separating” was corrected as “separation”.

(9) (Page 1, line 56) “several” was corrected as “a number of”.

(10) (Page 1, line 56) “with” was added.

(11) (Page 1, line 57) “could be” was added.

(12) (Page 4, line 134) “carefully” was deleted.

(13) (Page 4, line 141) “and” was deleted.

(14) (Page 5, line 148) “that” was added.

(15) (Page 5, line 149) “the” was deleted.

(16) (Page 5, line 152) “are observed” was added.

(17) (Page 5, line 158) “was” was corrected as “has a”.

(18) (Page 5, line 160) “reaction” was corrected as “process”.

(19) (Page 6, line 182) “analyze” was corrected as “analyzed”.

(20) (Page 6, line 185) “to” was added.

(21) (Page 6, line 185) “disintegrating” was corrected as “disintegrate”.

(22) (Page 7, line 198) “the” was added.

(23) (Page 7, line 198) “afford” was corrected as “afforded”.

(24) (Page 7, line 201) “and” was added.

(25) (Page 8, line 217) “groups” was deleted.

(26) (Page 8, line 223) “are” was added.

(27) (Page 10, line 239) “the” was deleted.

(28) (Page 10, line 240) “are” was corrected as “is”.

(29) (Page 10, line 244) “a” was added.

(30) (Page 11, line 257) “yield” was corrected as “yields”.

(31) (Page 12, line 270) “the” was added.

(32) (Page 12, line 270) “has” was deleted.

(33) (Page 12, line 271) “this” was corrected as “the”.

(34) (Page 13, line 278) “group” was deleted.

(35) (Page 13, line 279) “group” was corrected as “groups”.

(36) (Page 13, line 281) “found to be” was added.

(37) (Page 13, line 281) “the” was added.

(38) (Page 13, line 283) “group” was added”.

(39) (Page 14, line 297) “intermediate” was corrected as “intermediates”.

(40) (Page 14, line 297) “to form” was corrected as “affords”.

(41) (Page 15, line 325) “undergo” was corrected as “undergoes”.

(42) (Page 15, line 326) “and” was corrected as “which”.

(43) (Page 15, line 327) “participate” was corrected as “participates”.

(44) (Page 15, line 328) “and” was corrected as “which”.

(45) (Page 15, line 328) “formation of” was deleted.

(46) (Page 15, line 352) “following” was corrected as “followed”.

(47) (Page 15, line 352) “and” was added”.

(48) (Page 15, line 353) “respectively” was added”.

(49) (Page 15, line 352) “drying” was corrected as “dried”.

(50) (Page 15, line 355) “the” was added”.

(51) (Page 15, line 356) “showed” was corrected as “shown”.

 

Response to Reviewer 4

We are very grateful for the recommendations of Reviewer 4.( The authors further expanded this synthetic method to the construction of quinoline motif. The investigation was carefully achieved, and the paper is well written. The mechanism is suitably proposed, and mechanistic studies supported this hypothesis. I would recommend publication of this manuscript in catalysts.

1. For the 1st question of “Page 2, line 55: The word “Indolyl” should be corrected to “indolyl”.”.

Response: We thank Reviewer 4 very much for helping us correct the mistakes and errors, (Page 2, line 55) “Indolyl” was corrected as “indolyl”

2. For the 2nd question of “Page 4, line 118: The word “87%” should be corrected to “84%” according to the result of entry 5.”.

Response: We thank Reviewer 4 again for this, (Page 4, line 118) “87%” was corrected as “84%”.

3. For the 3rd question of “Page 5, Table 1: The authors should write the reaction temperature. In entry 11, the reaction temperature is unclear (111 ^oC: boiling point of toluene ?).”.

Response: We thank Reviewer 4 very much for this comment. we have revised the reaction temperature in the manuscript (the reaction temperature is 120 ºC).

4. For the 4th question of “Page 6, line 150: The word “moderate” should be corrected to “good (or excellent).”.

Response: We thank Reviewer 4 again for helping us correct the mistakes and errors, (Page 6, line 150) “moderate” was corrected as “good”.

5. For the 5th question of “Page 6, line 159: Reference about the synthesis of quinoline derivatives should be cited (H. Hikawa and I. Azumaya et al. Asian J. Org. Chem. 2022, e202200510).”.

Response: According to the suggestion of Reviewer 4, the reference was added in ref 24. As follows:

24. Nakayama, T.; Harada, S.; Kikkawa, S.; Hikawa, H.; Azumaya, I. Palladium‐Catalyzed Dehydrogenative Synthesis of Imidazoquinolines in Water. Asian J. Org. Chem. 2022, 11, e202200510; DOI:10.1002/ajoc.202200510.

 

 

 

 

If you have any questions concerning the manuscript, please feel free to contact me.

Thank you very much for your consideration.

With best regards

 

Prof. Dawei Wang

Jiangnan University

1800 Lihu Road,

Wuxi, 214122, P. R. China

Email: [email protected]

 

Author Response File: Author Response.doc

Round 2

Reviewer 3 Report

Authors have revised the manuscript well. It can now be accepted for publication.

Only minor changes are needed.