Nouvelles voies de synthèse des hétérocycles et des dipeptides à tête prosthétique

Abstract

In the first chapter, we developed a novel catalytic synthesis of 3,4- dihydropyrimidinones via Biginelli reaction in the presence of a bronsted ionic liquid [H-val] HSO4 as the reaction medium. Then, we performed the synthesis of thiazolo[3,2- a]pyrimidin-3(5H)-ones via Hantzsch thiazoles synthesis using bromide ethylacetoacetate as an alkylatig agent in refluxed acetone, this novel method allowed to prepare these fused heterocyclic compounds in good yields. Lability of hydrogens in previous derivatives allowed to prepare new 2-benzilidénethiazolo[3,2-a]pyrimidin-3(5H)-ones via two methods: divergent and convergent from DHPMs as starting materials. In addition in the second chapter, we were interested in the development of novel synthesis of 2-cyanopyridones via Hantzsch-like reaction using ammonium nitrate instead of the usually used ammonium acetate. Then we carried out several consecutive reactions on these heterocyclic compounds to achieve the desired products: oxadiazolopyridines. In the third chapter, we have prepared some dipeptide N-cyanopyridines from cyanopyridines by carrying out some consecutive reactions.