2-Amino-4-phenyl-4H,10H-1,3,5-triazino[1,2-a]benzimidazol-3-ium chloride

Abstract

2-Guanidinobenzimidazole condenses with benzaldehyde in the presence of hydrochloric acid to form 2-amino-3,4-dihydro-4-phenyl-1,3,5-triazino[1,2-a]benzimidazole, which was isolated as its hydrochloride, C15H14N5+·Cl−. The positive charge of the cation is formally placed on the double-bonded N atom of the dihydrotriazine ring. The six-membered dihydrotriazine that is fused with the benzimidazole ring system is relatively flat (r.m.s. deviation = 0.106 Å), with the methine C atom deviating most [0.164 (1) Å] from the mean-square plane. The phenyl ring connected to the methine C atom is disordered over two positions in a 0.558 (1):0.442 (1) ratio; the two orientations are aligned at 85.1 (1) and 89.6 (1)° with respect to the dihydrotriazine ring. In the crystal, adjacent cations and anions are linked by N—H...N and N—H...Cl hydrogen bonds, generating a double chain running along the b axis.