DCMCIT, AN ANALOG OF THE ANTITUMOR DRUGS MITOZOLOMIDE AND TEMOZOLOMIDE

The crystal structure of droimidazo[5,1-d]-1,2,3,5-tetrazine-8-carboxa mide, (1), C9H11ClN6O2, an analogue of the novel bicyclic antitumour a gents mitozolomide (2) and temozolomide (3), has been determined at 29 0 K. Although, as in structures (2) and (3), the imidazotetrazinone ri ng system is essentially planar, the substitution of the -CONH2 group at C8 by a -CON(CH3)2 group in (1) negates the possibility of forming an intramolecular hydrogen bond at either N7 or N1 and thus allows rot ation of this group about the C8-C81 bond by ca 45-degrees.