Synthesis of some new pyrimidine and fused pyrimidine derivatives (Part I)

2-Hydroxy- and 2-Mercapto-3,4-dihydro-4-oxo-6-(furyl)-pyrimidine-5-carbonitriles (3a, b) were synthesized by two different routes. Methylation of 3a with methyl iodide gave the S-methyl derivative 4, which could also be prepared by two other different methods. The reaction of 4 with phosphorous oxychloride yielded the 4-chloro-pyrimidine derivative 6, which reacted with hydrazine hydrate, aroylhydr-azines, thiourea and phenylhydrazine to form the tetra-substituted pyrimidine derivative (8), the triazolopyrimidine derivatives (14a, b), the mercapto compound 7 and the pyrazolo[3,4-d]pyrimidine derivative 11, respectively. Compound 7 reacted with chloroacetone and gave 15 which reacted with aromatic aldehydes affording the tricyclic compounds (16a, b). Reaction of 8 with carbon disulphide and/or nitrous acid yielded the pyrazolo[3,4-d]-S-triazolo-[3,4-d]pyrimidine 13 and 12, respectively.