SYNTHESIS OF AHYDRO-2,5-BIS(NITROIMINO)IMIDAZO-[4,5-D]IMIDAZOLE

Improved reaction conditions for the preparation of ydro-5-imino-2-(ni troimino)imidazo[4,5-d]imidazole (3) from 4,5-dihydroxy-2-nitroiminoim idazolidine (2) and guanidine hydrochloride are described. Treatment o f the hydrochloride salt of 3 with nitric acid at low temperature gene rates the nitrate salt of 3 and not tahydro-2,5-bis(nitroimino)imidazo [4,5-d]imidazole (1a) as previously reported. The bis(nitroimino) comp ound (1a) was obtained by slow addition of nitric acid to a mixture of the monohydrochloride salt of the bicyclic guanidine (3) and acetic a nhydride.