SYNTHESIS OF CONDENSED HETEROCYCLIC COMPOUNDS CONTANING NITROGEN

Abstract

This thesis includes three chapters; the frrst of which is a brief review on the recent methods utilized for the synthesis of various heterocycles condensed with the thieno [2,3-d]pyrimidine ring.

Chapter II is the discussion and results of the work carried out by the candidate. It deals with the versatility and regio selectivity of the annelation of a triazole ring to the thieno [2,3-d]pyrimidine.

Reaction of the hydrazine 115 with acetic acid resulted in the formation of two products as indicated by TLC and with time one of them was transformed to the other one. The disappeared product was considered to be the hydrazide 118 which can be isolated after 10 min. On the other hand, upon prolonged heating for 18h, the hydrazide 118 underwent a dehydrative cyclization to give a product whose structure may be given either the angular 120 or the linear 122 as a consquence of involving N-1 or N-3, respectivelly in the cyclization process. The formation of a mixture of 120 and 122 was not considered, since one of the components of the mix­ ture at an earlier stage of the reaction has been transformed to the other one. Moreover, the structure of the product should not be the one derived from the Dimroth rearrangment of either 120 or 122, because the action of alkali on the fmal product caused its rear­ rangement to an isomer which can be given the structure 124 or 126; otherwise the product from the reaction of 115 with acetic acid should not be changed by alkali if it has the structure 124 or 126.