SYNTHESIS OF CONDENSED NATROGEN HETEROCYCLES

Abstract

This thesis includes three chapters; the first of which is a brief re• view on the recent methods utilized for the synthesis of various hete• recycles condensed with the I,2,4 - riazine ring. Chapter Il is a discussion and results of the work carried out by >16o the candidate. it deals with the versatility and regioselectivity of the annelation of a triazole ring to phenanthro [9.10 -e ] [I.2,4/triazine. Thus, the reaction of the starting material - hydrazinophenanthro [9,10.e] .2.jriazine with. acetaldchyde and.aromatic aldehydes such as benzaldehyde and anisaldehyde gave the corresponding hydrazones II. Similarly, a series of the hydrazones IHI were prepared by the con• densation of I with monosaccharides, such as D-arabinose, D- Xylose, D-glucose, D-alactose and D- mannose. The dehydrogenative cyclisation of the prepared hydrazones H with SOCl, has been carried out. A model study was done on com• pound Ha whercby, Phenanthro [9.10-c) -3 - methyl - 1,2,4 - triazolo • [3.4-c][1.24]-riazine IVa was obtained. Alternative heating the hydrazine I with acetic acid gave phe• nanthro [9.10-e] -3- methyl- I.2.4- triazolo - {4.5-b] {1.2.4]- triazine V. The sruture of IVa and consequently its isomer V has been esta• blished by the synthesis of V from the condensation of Phenanthraqui• none VI with 4,5-diamino-3-methyl-I,2,4 -triazole VII. Acetylation of the sugar hydrazones HI with acetic anhydride in pyridine for 24 hours at room temperature gave peracetylated sugar -I•