Pr. Lowe et Ch. Schwalbe, DCMCIT, AN ANALOG OF THE ANTITUMOR DRUGS MITOZOLOMIDE AND TEMOZOLOMIDE, Acta crystallographica. Section C, Crystal structure communications, 50, 1994, pp. 1629-1631
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.