A bstract. Cyanothioacetoamide 1 reacts with sulphur in the presence of triethylamiiie to form the 2, 5-diamino-thiophene derivative 3 and in the presence of sodium ethoxide the 1, 4- dihydropyridine derivative 2, respectively. 3 easily undergoes ring opening to yield the butadiene derivative 6. Catalyzed by amine from 1, cyclic ketones, and sulphur the 2-spiro [thieno [2, 3-d] pyrimidine-4-thiones] 8 arise. Analogously to other cyanoacetic acid ...
