Molecules

58 KiB

Open AccessArticle

Regioselective Oxidation of 3-Substituted Pyridinium Salts

by Joel L. Terán, Dino Gnecco, Alberto Galindo, Jorge R. Juárez, Raúl G. Enríquez, Manuel Soriano and W. F. Reynolds

Molecules 2000, 5(10), 1175-1181; https://doi.org/10.3390/51001175 - 31 Oct 2000

Cited by 4 | Viewed by 8356

Abstract

(1'R)-(+)-3-Hydroxymethyl-1-(1'-phenyl-ethyl)-pyridinium chloride (1), 1-benzyl-3-[1', 3']-dioxolan-2'-yl-pyridinium chloride (2) and (2'S, 4'S, 5'R)-(-)-1-benzyl-3-(3',4'-dimethyl-5'-phenyl-oxazolidin-2'-yl)-pyridinium bromide (3), were transformed by oxidation with potassium ferricyanide into the corresponding 1H-pyridin-2-ones in excellent yields with high regioselectivity. Full article

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130 KiB

Open AccessArticle

One-pot Syntheses of Fused Quinazolines by Reaction of N-(2-Cyanophenyl)chloromethanimidoyl Chloride. I. A New Synthesis of 1,3-Oxazolo- and 1,3-Oxazino[2,3-b]quinazolines

by Hana Divišová, Helena Havlišová, Petr Borek and Pavel Pazdera

Molecules 2000, 5(10), 1166-1174; https://doi.org/10.3390/51001166 - 31 Oct 2000

Cited by 27 | Viewed by 6710

Abstract

12H-Benzo[1,3]oxazolo[2,3-b]quinazolin-12-imine (5a), 9-chloro-12Hbenzo[1,3]oxazolo[2,3-b]quinazolin-12-imine (5b), 2,3-dihydro-5H-[1,3]oxazolo[2,3-b]quinazolin-5-imine (5c), 2,3-dihydro-3,3-dimethyl-5H-[1,3]oxazolo[2,3-b]quinazolin-5-imine (5d) and 3,4--dihydro-2H,6H-[1,3]oxazino[2,3-b]quinazolin-6-imine (5e) were synthesized in a one-pot reaction of N-(2-cyanophenyl)chloromethanimidoyl chloride (1) with 2-aminophenols, 2-aminoethanol, and 3-aminopropanol in the presence of [...] Read more.

12H-Benzo[1,3]oxazolo[2,3-b]quinazolin-12-imine (5a), 9-chloro-12Hbenzo[1,3]oxazolo[2,3-b]quinazolin-12-imine (5b), 2,3-dihydro-5H-[1,3]oxazolo[2,3-b]quinazolin-5-imine (5c), 2,3-dihydro-3,3-dimethyl-5H-[1,3]oxazolo[2,3-b]quinazolin-5-imine (5d) and 3,4--dihydro-2H,6H-[1,3]oxazino[2,3-b]quinazolin-6-imine (5e) were synthesized in a one-pot reaction of N-(2-cyanophenyl)chloromethanimidoyl chloride (1) with 2-aminophenols, 2-aminoethanol, and 3-aminopropanol in the presence of a base. The course of the reaction was controlled by the temperature and the amount of base used. N-(2-Cyanophenyl)-(2-hydroxyanilino)methanimidoyl chloride (3a), 2-chloro-3-(2-hydroxyphenyl)-3,4-dihydroquinazolin-4-imine (4a) and 6-imino-2H, 3H, 4H, 6H, 11H-1,3-oxazino[2,3-b]-5-quinazolinium chloride (6) were identified as intermediates of the one-pot process. Full article

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431 KiB

Open AccessArticle

A New Pathway to 3-Hetaryl-2-oxo-2H-chromenes: On the Proposed Mechanisms for the Reaction of 3-Carbamoyl-2-iminochromenes with Dinucleophiles

by Sergiy M. Kovalenko, Igor E. Bylov, Konstantyn M. Sytnik, Valentyn P. Chernykh and Yaroslav V. Bilokin

Molecules 2000, 5(10), 1146-1165; https://doi.org/10.3390/51001146 - 31 Oct 2000

Cited by 45 | Viewed by 9179

Abstract

The present account summarizes the author's studies to elucidate the mechanisms of the recently reported rearrangements resulting from inter- and/or intramolecular reactions of 2-imino-2H-chromene-3-carboxamides with different dinucleophiles. Full article

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41 KiB

Open AccessArticle

Synthesis of New Bis-Alkylated Phosphono Alkenyl Acyclonucleosides : (Z) and (E)-Diethyl-2-(3-alkyl pyrimidin-1-yl)ethylen-1-yl Phosphonate

by A. Rochdi, M. Taourirte, H. B. Lazrek, J. L. Barascut and J. L. Imbach

Molecules 2000, 5(10), 1139-1145; https://doi.org/10.3390/51001139 - 31 Oct 2000

Cited by 8 | Viewed by 7496

Abstract

The E- and Z- phosphonoalkenyl acyclonucleosides of uracil and thymine were synthesized under Michael addition conditions. Introduction of an alkyl, alkenyl or alkynyl group at the N-3 position of the pyrimidine moiety was accomplished using potassium carbonate in DMF. Full article

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43 KiB

Open AccessArticle

Application of Flow Thermolysis in Organic Synthesis: Easy Access to α,ω-Bis Thienyl- and Bis Pyrrolyl- Alkanes from Methylene Derivatives of Meldrum's Acid

by Jean Claude Pommelet, Fanck Jourdain and Hamid Dhimane

Molecules 2000, 5(10), 1130-1138; https://doi.org/10.3390/51001130 - 31 Oct 2000

Cited by 5 | Viewed by 6468

Abstract

Thermal decomposition of Meldrum's acid derivatives and rearrangement of (alkylsulfanyl) or (propargylamino)methylene ketene intermediates leads in one step to bis thienyl- or bis pyrrolyl-alkanes. Full article

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Scheme 1

84 KiB

Open AccessArticle

Studies On Some Acid Divalent-Metal Nitrilotriacetate Complexes

by E. R. Souaya, W. G. Hanna, E. H. Ismail and N. E. Milad

Molecules 2000, 5(10), 1121-1129; https://doi.org/10.3390/51001121 - 31 Oct 2000

Cited by 50 | Viewed by 9513

Abstract

IR and ¹H-NMR studies on nitrilotriacetic acid (H₃NTA) suggest that the acid exists in the zwitterion form, which allows the existence of intermolecular hydrogen bonding. A tetrahedral structure is established for eleven (1:1) anhydrous acid-metal (II) nitrilotriacetates complexes. The ten [...] Read more.

IR and ¹H-NMR studies on nitrilotriacetic acid (H₃NTA) suggest that the acid exists in the zwitterion form, which allows the existence of intermolecular hydrogen bonding. A tetrahedral structure is established for eleven (1:1) anhydrous acid-metal (II) nitrilotriacetates complexes. The ten Dq values for the colored complexes were determined spectrophotometrically. The pK_a values for the eleven acid metal complexes [M(HNTA)].(OH₂)₃] were determined and compared with the corresponding pK_a values of the [M(OH₂)_n]⁺² ions and also with the log β1 values of the corresponding [M(NTA)]^-complexes. X-ray diffraction studies on the ligand and on eight of these complexes are described. Full article

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162 KiB

Open AccessArticle

Crystal Structure of Methyl 4-amino-4-cyano-4,6-dideoxy-2,3-O-isopropylidene-α-L-talopyranoside

by Miroslav Koóš, Bohumil Steiner, Júlia Mičová, Vratislav Langer, Marián Ďurík, Dalma Gyepesová and Ľubomír Smrčok

Molecules 2000, 5(10), 1113-1120; https://doi.org/10.3390/51001113 - 31 Oct 2000

Cited by 1 | Viewed by 5937

Abstract

The structure of methyl 4-amino-4-cyano-4,6-dideoxy-2,3-O-isopropylidene-α-Ltalopyranoside was established by X-ray analysis confirming a talo configuration at C-4 and suggesting a ¹C₄ conformation of the pyranose ring. The values of relevant torsion angles and calculated puckering parameters revealed a distortion into [...] Read more.

The structure of methyl 4-amino-4-cyano-4,6-dideoxy-2,3-O-isopropylidene-α-Ltalopyranoside was established by X-ray analysis confirming a talo configuration at C-4 and suggesting a ¹C₄ conformation of the pyranose ring. The values of relevant torsion angles and calculated puckering parameters revealed a distortion into the direction of ⁵E conformation, thus indicating a flattening at C-2. Full article

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53 KiB

Open AccessArticle

Synthesis of Novel 1-Substituted and 1,9-Disubstituted-1,2,3,4-tetrahydro-9H-Carbazole Derivatives as Potential Anticancer Agents

by N. A. M. M. Shmeiss, M. M.F. Ismail, A. M. Soliman and H. I. El-Diwani

Molecules 2000, 5(10), 1101-1112; https://doi.org/10.3390/51001101 - 31 Oct 2000

Cited by 13 | Viewed by 10306

Abstract

Condensation of 1-acetyl-1,2,3,4-tetrahydro-9H-carbazole (2) with some amino compounds furnished the corresponding imino derivatives 3a-e. Compound 3a reacted with chloroacetic acid and underwent cyclization to give the thiazolidine derivative 5. Also, treatment of 3c with thionyl chloride caused cyclization to yield the [1,2,6]thiadiazino derivative [...] Read more.

Condensation of 1-acetyl-1,2,3,4-tetrahydro-9H-carbazole (2) with some amino compounds furnished the corresponding imino derivatives 3a-e. Compound 3a reacted with chloroacetic acid and underwent cyclization to give the thiazolidine derivative 5. Also, treatment of 3c with thionyl chloride caused cyclization to yield the [1,2,6]thiadiazino derivative 6, which gave the corresponding N-formyl derivative 7 upon heating with ethyl formate. In addition, interaction of 3d with ethyl cyanoacetate yielded the monoamide of malonic acid derivative 8. Acylation of carbazole 1 with succinoyl chloride or phenylacetyl choride produced the corresponding azepine (11) and 1,9-diphenyl acetyl derivatives (14), respectively. Compounds 11, 14 were further reacted to give the carbazole derivatives 12, 13 and 15a,b. The cytotoxic activity for some of the prepared compounds against breast cancer B₂₀ is discussed. Full article

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74 KiB

Open AccessArticle

Synthesis of Regioselectively Protected Protocatechuic Acid Derivatives by Biomimetic Transformation of Quinic Acid

by Armandodoriano Bianco, Francesco Bonadies and Cristiana Melchioni

Molecules 2000, 5(10), 1094-1100; https://doi.org/10.3390/51001094 - 31 Oct 2000

Cited by 1 | Viewed by 8934

Abstract

3- and 4-monoesterified protocatechuic acid methyl ester (5 and 7 respectively) have been synthesised from quinic acid by a high yields biomimetic rearrangement. Full article

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37 KiB

Open AccessArticle

Synthesis and Reactions of Substituted 3-amino-2-furyl(aryl)-thieno[2,3-b]pyridines

by Ye. A. Kaigorodova, V. K. Vasilin, L. D. Konyushkin, Ye. B. Usova and G. D. Krapivin

Molecules 2000, 5(10), 1085-1093; https://doi.org/10.3390/51001085 - 31 Oct 2000

Cited by 14 | Viewed by 7690

Abstract

New substituted thieno[2,3-b]pyridines which contain 4-nitropehnyl and 5-nitro-, carboxy-, methoxycarbonyl-2-furyl groups in the 2 position have been obtained. Full article

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15 KiB

Open AccessArticle

Interaction of 1,5-Substituted Pyrrolin-2-ones with Dichlorocarbene under Phase Transfer Catalysis Conditions

by Alevtina Yu. Egorova, Valentina A. Sedavkina and Zlata Yu. Timofeyeva

Molecules 2000, 5(10), 1082-1084; https://doi.org/10.3390/51001082 - 31 Oct 2000

Cited by 3 | Viewed by 7262

Abstract

Treatment of 5-alkyl(aryl)-3H-pyrrolin-2-ones with dichlorocarbene under phase transfer catalysis conditions at 20-30ºC results in a cycloaddition of the carbene to the C=C bond followed by skeletal rearrangement. Full article

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Scheme 1

20 KiB

Open AccessCommentary

Free Access or Free Publication

by Derek J. McPhee and Shu-Kun Lin

Molecules 2000, 5(10), 1080-1081; https://doi.org/10.3390/51001080 - 13 Oct 2000

Viewed by 5126

Abstract

Since its inception Molecules has been published on the Internet under a policy of providing "free subscription" based access, limited lately to the current issue, with archival access only provided to paid subscribers.[...] Full article

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Molecules, Volume 5, Issue 10 (October 2000) – 12 articles , Pages 1080-1181

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