A convenient synthesis of thiazolo [3,2-a]-and triazolo[4,3-a]-pyrimidines and pyrimido [2,l-c] triazine derivatives

Abstract EN

Alkylation of 4-oxo-6-phenyl-2-thioxo-1,2,3,4-tetrahydropyrimidine- 5-carbonitrile (1) gave the S-alkyl derivatives (2b,c).

Compound (2c) could be cyclised into 3-methyl-5-oxo-5H-7-phenylthiazolo[3,2-a] pyrimidine-6-carboxamide (3).

Further substitution of compounds (2a,b) yielded the N3-Substituted pyrimidine derivatives (7a-e).

Desulphunisation of each of compounds (2a,b) with benzhydrazide resulted in the formation of 2-(2-benzoylhydrazino)- pyrimidine derivative (9), which could be converted into the triazolo[4,3-a] pyrimidine (11).

Each of compounds (2a,b) reacted with semicarbazide to produce directly the dioxotriazolopyrimidine derivative (14).

Treatment of the 2-hydrazinopyrimidine derivative (10) with chloroacetyl chloride afforded the pyrimido[2,1-c]triazine derivative (16).

Its isomeric compound (17) could be also prepared.

The structures of the newly synthesized compounds were proved by chemical routes and spectral studies.