2-Alkylmercapto- 4-Chloro-6-phenyl-pyrimidine-5-carbonitrile (4a-c) were synthesized and converted into 2-alkylmercapto 4-mercapto-6-
phenyl-pyrimidine-5-carbonitriles (7a-c). Compounds (7a-b) were alkylated with halogenated compounds to afford compounds (8a-g).
Compounds (8a-g) underwent Thorpe-Ziegler Cyclization to give thienopyrimidines (9a-g). 5-Amino-2-alkylmercapto-4-phenyl-thieno-
[2,3-d]pyrimidine-6-carboxamide derivatives (9a-f) underwent cyclization reaction using triethyl orthoformate to afford pyrimidothienopyrimidines
(10a-e).