Synthesis of some 2,3-diaryl-quinoline-6-isoxazyle-4-carboxylic acid derivatives

Abstract

A series of some new substituted quinolines were synthesized by Doebner reaction, a three component coupling of various aromatic amines with two aldehydes and phenyl pyruvic acid. The substituted 2,3-diary-6-acetyl-quinoline-4-carboxylic acids reacted with various aromatic aldehydes in the presence of basic medium using Claisen-Schmidt condensation to afford the corresponding chalcones. The substituted chalcones, on condensation with hydroxylamine hydrochloride in ethanol furnished isoxazoles derivatives. Other quinoline derivatives were synthesized in this study by using an aryl amine with acetylacetone as Combes reaction, Knorr reaction between aryl amine and ethylacetoacetate with heating above 100ºC and Conrad-Limpach quinoline synthesis a thermal condensation of aryl amine with ethylacetoacetate. The synthetic design of these compounds was achieved through retrosynthetic analysis (RSA) approach. The reaction progress for all synthesized compounds was checked by (TLC) and m.p techniques, and the structures of synthesized compounds were confirmed using IR, 1HNMR, 13CNMR, and GC-MS. All the compounds have been screened for their antibacterial and antifungal activity, the most active compounds were those bearing sulphonamide group in position six of 3-phenyl-quinoline derivatives, hydroxyphenyl group which linked with propen-2-one of chalcones, two active compounds appear in isoxazoles those were bearing phenyl group in position six and hydroxyphenyl group which linked with proper- 2-one, 2-methyl, 4-hydroxy group appear as the most active compound of quinoline derivatives.