Synthèse et fonctionnalisation de nouveaux systèmes azahétérocycliques.

Abstract

: Nitrogen heterocycles are the structural unit of many natural or synthetic biological molecules. There are numerous syntheses of these compounds described in the literature. In this work, we considered three new synthetic approaches for the synthesis of 2-aminopyridines, 4- aminopyrido [2,3-d] pyrimidines and 4-aminochroméno [2,3-d] pyrimidines under green conditions. The present thesis is divided into three great parts: The first part is divided into two sections: the first one relates the synthesis of 2-aminopyridines by a new easy and efficient way according to different conditions, using arylidenemalononitriles as main precursors. The second one is based on the study of arylidene-malononitriles reactivity with a variety of compounds to synthesize various heterocycles. The second part describes two new strategies for the synthesis of 4-aminopyrido [2,3-d]pyrimidines. The first strategy is to use as a starting material the formamidines and the second way is the use of 2-aminopyridines in "one pot" process with three components. These are two new quick and efficient routes to obtain 4-aminopyrido [2,3-d] pyrimidines. The third part of this work is devoted to the synthesis of 4-aminochromeno[2,3-d]pyrimidines and its analogs (4,8-diacetoxy-2-methyl-5H-chromeno[2,3-d]pyrimidines) by a nucleophile addition of formamidine acetate or acetic anhydride with 2-amino-4H-chromene-3-carbonitriles. This method allows direct access to the desired heterocyclic without solvent.