名称:
Heterocyclic ring-closure reactions. 8. Reactions of isothiocyanates with cyanothioformamides. Cyclization of 5-imino-4-thioxo-2-imidazolidones and 5-imino-2,4-imidazolidinedithiones to 5,7-dihydrodiimidazo[4,5-b:4',5'-e]pyrazine-2,6(1H,3H)-diones and -dithiones