8-ACID DERIVATIVE OF THE ANTITUMOR AGENT MITOZOLOMIDE

The crystal structure of ydro-4-oxoimidazo[5,1-d][1,2,3,5]tetrazine-8- acid, C7H6ClN5O3, a derivative of the novel bicyclic antitumour agent mitozolomide, 3-(2-chloroethyl)-3,4-dihydro-4-oxoimidazo[5, 1-d][ 1,2, 3,5]tetrazine-8-carboxamide, has been determined at 293 K. The expecte d dimer, hydrogen bonded via the two carboxyl groups, does not occur. In preference, the two molecules in the asymmetric unit utilize hydrog en bonding between the carboxyl group of one and the N atom and CH in the imidazo ring of the other. These two then further interact via the same scheme with their centrosymmetrically related pair to produce a fully hydrogen-bonded planar tetramer.