Novel Biopolymer-Based Catalyst for the Multicomponent Synthesis of N-aryl-4-aryl-Substituted Dihydropyridines Derived from Simple and Complex Anilines
Abstract
:1. Introduction
2. Results and Discussion
2.1. Catalyst Screening and Condition Optimisation
2.2. Expanding the DHP Substrate Scope
2.3. Catalyst Description and Recycling Runs
2.3.1. Optical Microscopy
2.3.2. IR Spectrum
2.3.3. Recycling Runs and Hot Filtration Test
2.4. Green Metrics of Model Reaction
2.5. DHPs Derived from the Products of the Aza-Friedel–Crafts Multicomponent Reaction
2.6. DHP Characterisation by Single and Two-Dimensional NMR Methods
- (1)
- C15 is long-range coupling with H13 only, hence confirming the above methylene assignment. Simultaneously, C10 and C11 are both coupled to H16, but not to H13.
- (2)
- H20 and 21 are long-range-coupled with C17, but H18 and 19 are not. This may seem strange but, in some instances (especially in para-substituted systems with chemically equivalent hydrogens on either side of the aromatic ring), the HMBC quantum filter removes two-bond correlations (along with single-bond correlations), leaving only three/four-bond correlations. In fact, C3 gives a cross-peak with H2 and 6 (three-bond correlation), while it does not with H1 and 5. In addition, there are two peaks, which are denoted as 20–21 and 18–19 due to three-bond correlations (H20-C21 or H21-C20 for the former and H18-C19 or H19-C18 for the latter).
- (3)
- H2 and 6 and H1 and 5 both give cross-peaks with C2,6 and C1,5, respectively. This may appear incorrect, but what is actually happening is a correlation between H2 and C6 or between C2 and H6 (three bond correlations), similar to what is observed between H/C 20–22.
- (4)
- H1 and 5 give a cross-peak with C4 (three-bond correlation). The identity of C4 is confirmed because it undergoes correlation with H7. Meanwhile, C3 is correlated to the methyl hydrogens H29 and with H2 and 6, as already mentioned.
- (5)
- H7 carries out long-range coupling with both C10 and C11, with C10 also carrying out long-range coupling with H16 (confirming the assignments of methylene hydrogens). H7 also carries out long-range coupling with C9, C8, C23, C4, C2, and 6.
- (6)
- H29s are able to give cross-peaks with C1 and 5 (three-bond correlation).
- (7)
- C15 carries out long-range three-bond coupling with H13 (visible cross-peak in expanded inset image), hence confirming the earlier assignments of the methylene hydrogens.
- (8)
- C8 is involved in long-range coupling with H7 (strongly), H16 (strongly), and with H13 (barely visible).
- (9)
- C9 is involved in long-range coupling with H7 (two-bond correlation) and H25 (three-bond correlation). The two-bond correlation between C9 and H7 is detected because of a small J coupling constant between the two that allows for peaks not to be filtered out by quantum filtering.
- (10)
- C23 is involved in long-range coupling (three-bond), with H7 confirming its identity.
3. Experimental
3.1. General Reaction Procedure
3.2. Pip–Agar Catalyst Preparation and Alkalinity Determination
3.3. Other Catalyst Preparations
3.4. Product Characterization Procedure
3.5. Product Characterization Data
4. Conclusions
Supplementary Materials
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
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Entry a | Catalyst b | Amount of Catalyst | Temperature (°C)/Time (hr) | Solvent/Amount (mL) | Molar Ratio 1a/2a/3a/4a | Yield of 5a (%) c |
---|---|---|---|---|---|---|
1 | Pip-A15 (2.72 mmol/g) | 20 mol% | 85/7 + 7 | EtOH/2 | 1:1:1:1 | 64% |
2 | 20 mol% | 85/2 + 7 | EtOH/2 | 1:1:1:1 | 47% | |
3 | 20 mol% | 85/7 + 1 | EtOH/2 | 1:1:1:1 | 11% | |
4 | 20 mol% + 0.2 g 4 Å MS f | 85/7 + 7 | EtOH/2 | 1:1:1:1 | 71% | |
5 | 20 mol% + 0.4 g 4 Å MS f | 85/7 + 7 | EtOH/2 | 1:1:1:1 | 52% | |
6 | 30 mol% | 85/7 + 7 | EtOH/2 | 1:1:1:1 | 63% | |
7 | 30 mol% | 85/7 + 16 | EtOH/2 | 1:1:1:1 | 74% | |
8 | Ethylenediamine-A15 (2 mmol/g) | 25 mol% | 85/7 + 7 | EtOH/2 | 1:1:1:1 | 63% |
9 | Morpholine-A15 (2.00 mmol/g) | 20 mol% | 85/7 + 7 | EtOH/2 | 1:1:1:1 | - |
10 | Pip–Dowex (2.4 mmol/g) | 20 mol% | 85/7 + 16 | EtOH/2 | 1:1:1:1 | 67% |
11 | 25 mol% | 85/7 + 16 | EtOH/2 | 1:1:1:1 | 70% | |
12 | 25 mol% | 95/7 + 16 | i-PrOH/2 | 1:1:1:1 | 65% | |
13 | Pip–Dowex (2.1 mmol/g) | 40 mol% | 85/7 + 7 85/7 + 12 | EtOH/2 | 1:1:1:1 | 66% 69% |
14 | 40 mol% | 85/7 + 7 | EtOH/2 | 1:1:1:1.2 | 61% | |
15 | 30 mol% | 85/7 + 7 | EtOH/2 | 1:1:1:1.2 | 67% | |
16 | 30 mol% | 85/7 + 7 | EtOH/2 | 1:1.3:1:1.3 | 82% g | |
17 | Cell-NH2 (0.5 mmol/g) | 5 mol% | 90/4 + 4 | EtOH/2 | 1:1:1:1 | 48% |
18 | 20 mol% | 85/7 + 16 | EtOH/2 | 1:1:1:1 | 46% | |
19 | A21 (dry) | 0.2 g | 85/7 + 8 | EtOH/2 | 1:1:1:1 | 53% |
20 | A26 (dry) | 0.3 g | 85/7 + 14 | EtOH/2 | 1:1:1:1 | 22% |
21 | MgO | 40 mol% | 85/7 + 4 | EtOH/2 | 1:1:1:1 | 57% |
22 | 20 mol% | 85/7 + 7 | EtOH/2 | 1:1:1:1 | 61% | |
23 | MgO-SiO2 (63–200 um) (4 mmol/g) | 10 mol% | 85/7 + 7 | EtOH/2 | 1:1:1:1 | 42% |
24 | 20 mol% | 85/7 + 7 | EtOH/2 | 1:1:1:1 | 46% | |
25 | MgO-nano-MCM41 (4.5 mmol/g) | 20 mol% | 85/7 + 16 | EtOH/2 | 1:1:1:1 | 60% |
26 | CaO–Boehmite (20% w/w, 3.6 mmol/g) | 10 mol% | 85/7 + 7 | EtOH/2 | 1:1:1:1 | 54% |
27 | SnO-MK30 (1 mmol/g) | 10 mol% | 85/7 + 7 | EtOH/2 | 1:1:1:1.2 | 52% |
28 | ZnO–Cellulose | 0.1 g | 85/7 + 7 | EtOH/2 | 1:1:1:1.2 | 67% |
29 | 0.125 g | 85/7 + 7 | EtOH/2 | 1:1:1:1.2 | 57% | |
30 | 0.08 g | 85/7 + 7 | EtOH/2 | 1:1:1:1.2 | 43% | |
31 | WSi-MK30 (10% w/w) | 0.1 g (0.3 mol%) | 85/7 + 7 | EtOH/2 | 1:1:1:1.2 | 65% |
32 | PW-MK30 (10% w/w) | 0.1 g (0.3 mol%) | 85/7 + 7 | EtOH/2 | 1:1:1:1.2 | 59% |
33 | MK30-nano-Fe3O4 | 0.1 g | 85/7 + 7 | EtOH/2 | 1:1:1:1.2 | 70% |
34 | 0.1 g | 85/7 + 7 | EtOH/2 | 1:1.3:1:1.3 | 79% g | |
35 | 0.125 g | 85/7 + 7 | EtOH/2 | 1:1:1:1.2 | 67% | |
36 | 0.075 g | 85/7 + 7 | EtOH/2 | 1:1:1:1.2 | 61% | |
37 | 0.1 g | 85/7 + 7 | EtOH/H2O (7:3)/2 | 1:1:1:1.2 | 65% | |
38 | 0.1 g + 0.1 g 4 Å MS f | 85/7 + 7 | EtOH/2 | 1:1:1:1.2 | 70% | |
39 | 0.1 g | 85/12 + 7 | EtOH/2 | 1:1:1:1.2 | 72% | |
40 | 0.1 g | 85/7 | EtOH/2 | 1:1:1:1.2 | 70% h | |
41 | Pip–Agar (1.10 mmol/g) | 25 mol% | 85/7 + 7 | EtOH/2 | 1:1.3:1:1.3 | 80% g |
42 | 20 mol% | 85/7 + 7 | EtOH/2 | 1:1.3:1:1.3 | 76% g | |
43 | 25 mol% | 85/7 + 7 | EtOH/2 | 1:1:1:1.2 | 70% | |
44 | 85/7 + 8 | EtOH/2 | 1:1:1:1.2 | 80% i | ||
45 | 17 mol% | 85/7 + 7 | EtOH/2 | 1:1:1:1.2 | 61% | |
46 | Ethylenediamine diacetate–Agar (1 mmol/g) | 20 mol% | 85/7 + 7 | EtOH/2 | 1:1:1:1.2 | 65% |
47 | Hexamine–Agar (1 mmol/g) | 20 mol% | 85/7 + 16 | EtOH/4 | 1:1:1:1.2 | 44% |
48 | DABCO–Agar (1 mmol/g) | 20 mol% | 85/7 + 16 | EtOH/4 | 1:1:1:1.2 | 68% |
Entry a | Amine (1) | Aldehyde (2) | Diketone (3) | Active-Methylene Compound (4) | Yield % (Time, hrs) b [Product Code] |
---|---|---|---|---|---|
1 | C6H5NH2 (1a) | 4-Me-C6H4CHO (2b) | (3a) | X = CN (4a) | 71% (7 + 8) [5b] |
2 | 1a | 4-Cl-C6H4CHO (2c) | 3a | 4a | 78% (7 + 8) [5c] |
3 | 1a | 2,4-Cl2-C6H3CHO (2d) | 3a | 4a | 80% (7 + 8) [5d] |
4 | 1a | 4-F-C6H4CHO (2e) | 3a | 4a | 72% (7 + 8) [5e] |
5 | 1a | (2f) | 3a | 4a | 49% (7 + 8) [5f] |
6 | 1a | 3-NO2-C6H4CHO (2g) | 3a | 4a | 79% (7 + 8) [5g] |
7 | 1a | 4-OCH3-C6H4CHO (2h) | 3a | 4a | 58% (7 + 8) [5h] |
8 (Novel) | 1a | 2d | 3a | X = COOMe (4b) | 25% (7 + 8) [5i] |
9 (Novel) | 3-Me-C6H4NH2 (1b) | 2g | 3a | 4a | 84% (7 + 8) [5j] |
10 (Novel) | 3-Cl-C6H4NH2 (1c) | 2d | 3a | 4a | 83% (7 + 8) [5k] |
11 (Novel) | 3-NO2-C6H4NH2 (1d) | 2d | 3a | 4a | 84% (7 + 8) [5l] |
12 (Novel) | 4-OCH3-C6H4NH2 (1e) | 3-Me-C6H4CHO (2i) | 3a | 4a | 45% (7 + 8) [5m] |
13 (Novel) | BnNH2 (1f) | 2d | 3a | 4a | 10% (7 + 8) [5n] |
14 | c-hexylNH2 (1g) | 2g | 3a | 4a | −(7 + 5) c [5o] |
15 (Novel) | (1h) | 4-CN-C6H4CHO (2j) | 3a | 4a | 53% (7 + 8) [5p] |
16 (Novel) | (1i) | 2d | 3a | 4a | 23% (7 + 9) [5q] |
17 | 1a | 2a | (3b) | 4a | −(7 + 2) d [5r] |
18 | 1a | 2b | (3c) | 4a | 65% (7 + 8) [5s] |
19 | 1a | 2c | 3c | 4a | 64% (7 + 8) [5t] |
Entry a | Aniline R1 (Reactant Code) | Yield % (Time, hrs) b [Product Code] |
---|---|---|
1 | H (1a) | 78% (7 + 8) [7a] |
2 (Novel) | 3-Me- (1b) | 19% (7 + 8) [7b] |
3 (Novel) | 3-NO2- (1d) | 79% (7 + 8) [7c] |
4 | 4-OCH3- (1e) | 60% (7 + 8) [7d] |
5 | 4-Cl- (1j) | 68% (7 + 8) [7e] |
6 | 4-Br- (1k) | 72% (7 + 8) [7f] |
7 | 4-Cl- (1l) | 20% (7 + 8) [7g] |
8 | (1h) | - [7h] |
9 (Novel) | 3-Cl- (1c) | 53% (7 + 8) [7i] |
Total mass of waste = mass of starting materials − (mass of product + mass of recovered catalyst) Total mass of reactants = 0.00125 × (140.18 + 93.13 + 106.12) = 0.507 g Total mass of catalyst = 0.28 g (complete mass recovery) Total mass of solvent = 2 mL × 0.789 g/mL = 1.578 g Total mass of product = 0.80 × 369.46 × 0.00125 = 0.369 g Hence, |
Paper Authors (Year) [Reference] | Conditions | Main Advantages | Main Drawbacks |
---|---|---|---|
Singh, S.K. et al. (2012) [16] | 5 mol% DBU MW (140/120 W) EtOH, 80 °C, 3–5 min 92–99%, 23 examples | Short reaction time, excellent yields | Homogeneous catalyst (non-recoverable) No substituted anilines and no isatin used Pre-formed pure enaminone |
Abaszadeh, M. et al. (2015) [12] | 55 mol% MgO EtOH, 17–43 min 87–92%, 18 examples | Short reaction time, excellent yields | No recycling runs Metallic catalyst No substituted anilines and no isatin used Preformed enaminone |
Abaszadeh, M. et al. (2015) [13] | 10 mol% ZnO EtOH, 80 °C, 27–55 min 88–92%, 18 examples | Short reaction time, excellent yields Recyclable | Metallic catalyst No substituted anilines and no isatin used Preformed pure enaminone |
Abaszadeh, M. et al. (2016) [14] | 10 mol% Fe3O4 EtOH, 80 °C, 4–15 min 87–95%, 20 examples | Short reaction time, excellent yields | Metallic catalyst No substituted anilines and no isatin used Preformed pure enaminone No recycling runs |
Abasadeh, M. et al. (2016) [18] | 30 mol% Crown ether EtOH/H2O, reflux 12–20 min 87–91%, 16 examples | Short reaction time, excellent yields | No substituted anilines and no isatin used No recycling runs Preformed pure enaminone |
Sanaei-Rad, S. et al. (2021) [19] | MIL-101(Cr) Neat, reflux 10–20 min 92–98%, 14 examples | Short reaction time, excellent yields, recyclable catalyst, one-pot method | Toxic metal containing catalyst (Cr) Hazardous solvents in catalyst preparation No heteroaromatic aldehydes and no isatin used |
This study | 25 mol% pip–agar EtOH, 7 + 8 hrs 27 examples | Cheap metal-free easy-to-prepare biopolymer catalyst Recyclable Union of MCRs possible Use of substituted anilines and isatin One-pot method | Long reaction times |
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Bosica, G.; Abdilla, R. Novel Biopolymer-Based Catalyst for the Multicomponent Synthesis of N-aryl-4-aryl-Substituted Dihydropyridines Derived from Simple and Complex Anilines. Molecules 2024, 29, 1884. https://doi.org/10.3390/molecules29081884
Bosica G, Abdilla R. Novel Biopolymer-Based Catalyst for the Multicomponent Synthesis of N-aryl-4-aryl-Substituted Dihydropyridines Derived from Simple and Complex Anilines. Molecules. 2024; 29(8):1884. https://doi.org/10.3390/molecules29081884
Chicago/Turabian StyleBosica, Giovanna, and Roderick Abdilla. 2024. "Novel Biopolymer-Based Catalyst for the Multicomponent Synthesis of N-aryl-4-aryl-Substituted Dihydropyridines Derived from Simple and Complex Anilines" Molecules 29, no. 8: 1884. https://doi.org/10.3390/molecules29081884