Reaction of 2-chloromethylquinazoline-4(3H)-one with some 3-cyanopyridine-2(1H)-thiones gave the
corresponding thioethers which upon treatment with appropriate base, underwent intramolecular ThorpeZeigler reaction affording the isomeric 3-amino-2-(3,4-dihydro-4-oxo-2-quinazolinyl)thieno[2,3-b]pyridines. In
contrast, the reaction of 2-chloromethylquinazoline-4(3H)-one with 3-cyanoquinoline-(1H)-thione gave 3-
amino-2-(3,4-dihydro-4-oxo-2-quinazolinyl)thieno[2,3-b]quinoline directly. Reaction of the resulting
aminothienopyridines/quinoline with some reagents namely; acetic anhydride, triethyl orthoformate and/ or
nitrous acid were carried out and their products were identified