- Synthesis of Quinoline-4-carboxamides and Quinoline-4-carboxylates via a Modified Pfitzinger Reaction of N-Vinylisatins
-
A synthetic approach for the accelerated assembly of quinoline-4-carboxamide and quinoline-4-carboxylate nuclei is presented. The methodology is based on the rearrangement of N-vinylisatins promoted by different types of amines (or ethanol) in a Pfitzinger-type mechanism that, in turn, builds the quinoline ring system. The reaction took place only by heating the starting materials in ethanol, without any additive.
- Mijangos, Marco V.,Amador-Sánchez, Yoarhy A.,Miranda, Luis D.
-
p. 637 - 647
(2021/01/25)
-
- SYNTHESIS OF QUINOLINE-4-CARBOXYLIC ACID AND ITS DERIVATIVES
-
2-Methylquinoline-4-carboxylic acid was obtained by the reaction of isatin with acetone in the presence of alkali.This acid was converted through a step involving (E)-2-styrylquinoline-4-carboxylic acid to quinoline-2,4-dicarboxylic acid, from which quinoline-4-carboxylic acid was obtained by refluxing in nitrobenzene.The structures of the synthesized compounds were confirmed by 1H NMR spectroscopy using two-dimensional (2DJ) spectra.
- Brasyunas, V.B.,Andreyanova, T.A.,Safonova, T.S.,Solov'eva, N.P.,Turchin, K.F.,Sheinker, Yu.N.
-
p. 670 - 673
(2007/10/02)
-
- Photochemical Reaction of Ethoxycarbonyl-Substituted Quinolines
-
The photochemical reactions of the quinoline derivatives substituted by an ethoxycarbonyl group at the 2-, 3-, and 4-positions of a quinoline nucleus have been investigated in several alcohols and cyclohexane.Irradiation of ethyl 4-quinolinecarboxylate (1) yielded ethyl 2-hydroxyalkyl-4-quinolinecarboxylates (4a-c) in alcohols and ethyl 2-cyclohexyl-4-quinolinecarboxylate (4d) in cyclohexane in a good yield, respectively.The photochemical reactions of ethyl 3-quinolinecarboxylate (2) showed remarkable solvent dependency.Irradiation in methanol and cyclohexane afforded a solvent-additive product, ethyl 4-hydroxymethyl-1,4-dihydro-3-quinolinecarboxylate (5a) and ethyl 4-cyclohexyl-1,4-dihydro-3-quinolinecarboxylate (5b), while such photoaddition of the solvent did not proceed in ethanol and 2-propanol but instead ethyl 1,4-dihydro-3-quinolinecarboxylate (6) and dimeric compounds were formed, both of which were unstable and finally reverted to 2 at room temperature in air.In the case of ethyl 2-quinolinecarboxylate two types of the products, ethyl 4-hydroxyalkyl-1,4-dihydro-2-quinolinecarboxylate (7) and ethyl 1,4-dihydro-2-quinolinecarboxylate (8) were obtained in ethanol and 2-propanol but the yields of those products were poor.On the basis of triplet quenching experiments, the photochemical reactions of those ethyl quinolinecarboxylates are suggested to occur through hydrogen abstraction from the solvents by the ring nitrogen in the S1 state.
- Ono, Isao,Hata, Norisuke
-
p. 2891 - 2898
(2007/10/02)
-
- HOMOLYTIC ALKOXYCARBONYLATION REACTIONS IN TWO-PHASE SYSTEMS, PART II. STUDIES ON THE ETHOXYCARBONYLATION OF SOME SELECTED ?-DEFICIENT N-HETEROAROMATIC SYSTEMS
-
A systematic study on the homolytic substitution of pyridine, quinoline and pyrazine by ethoxycarbonyl radicals was performed.It is demonstrated that under appropriate conditions Minisci-type alkoxycarbonylation reactions can provide convenient access to heteroaromatic monocarboxylic acid esters, like alkyl 2-pyrazinecarboxylates and alkyl 4-alkyl-2-pyridinecarboxylates.
- Heinisch, Gottfried,Loetsch, Gerhard
-
p. 5973 - 5977
(2007/10/02)
-