Preparation of some 3,6-disubstituted 2-methylquinolin-4-ol and 3,6-disubstituted 4-methylquinolin-2-ol derivatives

Abstract

The chemistry of quinoline derivatives including their preparations, reactions together with a review of their most important biological activity were dealt with in chapter one. 3,6-disubstituted 2-methyl quinolin-4-ol and 3,6-di substituted 4-methyl quinoline-2-ol derivatives were prepared by Conrad Limpach Knorr method, kinetically and thermodynamically. Eight final compounds were prepared in this work, together with their corresponding intermediates in multiple step synthesis. In the first step the diazonium ion was formed from the reaction of aromatic amines with nitrous acid and coupling reaction of diazonium products with active methylene compound (ethyl-3-oxobutanoate). The second step reaction of diazotized dicarbonyl compounds with aromatic amine (aniline, sulphanilamide) in presence of hydrochloric acid in two different conditions (room temperature, 70-80οC), were carried out. The third step is cyclization using sulphuric acid at high temperature. The reaction course was followed with thin layer chromatography (TLC), the identity of products was determined through IR, H1NMR. The retrosynthetic analysis of the compounds was discussed in chapter three together with suitable mechanism of each reaction. The spectral data were interpretated and discussed in the same chapter, the results obtained were agreed will with synthyzed compounds.