Abstract
The reaction of 2-mercapto-6,7,8,9-tetrahydro-3
H
-benzo[4,5]thieno[2,3-
d
]pyrimidin-4-one or its 2-methylthio derivative with hydrazonoyl halides, in the presence of triethylamine, yielded 6,7,8,9-tetrahydrobenzo[4,5]thieno[2,3-
d
]-1,2,4-triazolo[4,5-
a
]pyrimidin-5-ones. The structure of the latter compounds was further confirmed by reaction of 2-mercapto-6,7,8,9-tetrahydro-3
H
-benzo[4,5]thieno[2,3-
d
]pyrimidin-4-one with the appropriate active chloromethylenes followed by coupling of the products with benzenediazonium chloride to afford the non-isolable azo-coupling products which converted, in situ, to 6,7,8,9-tetrahydrobenzo[4,5]thieno[2,3-
d
]-1,2,4-triazolo[4,5-
a
]pyrimidin-5-ones. The reaction mechanism was proposed and the products were screened for their biological activity. Some of the newly synthesized compounds had a moderate effect against some bacterial and fungal species.
Graphical abstract