Synthesis of Hexa- and Octahydropyrido[3'2':4,5]thieno[3,2-d]pyrimidines

The reaction of N-methylmorpholinium 4-(2-chlorophenyl)-5-cyano-2-oxo-1,2,3,4-tetrahydropyridine-6-thiolate with chloroacetamide in DMF in the presence of an excess of KOH gave 3-amino-2-carbamoyl-4-(2-chlorophenyl)-6-oxo-4,5,6,7-tetrahydrothieno2,3-b]pyridine. Refluxing the latter with acyl chlorides in AcOH or heating in formic acid gave hexahydropyrido3',2':4,5]thieno3,2-d]pyrimidine derivatives and reaction with cyclohexanone gave a spiro-linked octahydropyrido3',2':4,5]thieno3,2-d]pyrimidine.