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

2-Guanidinobenzimidazole condenses with benzaldehyde in the presence of hydro-chloric acid to form 2-amino-3,4-dihydro-4-phenyl-1,3,5-triazino[1,2-a]benzimidazole, which was isolated as its hydro-chloride, C(15)H(14)N(5) (+)·Cl(-). The positive charge of the cation is formally placed on the double-bonded N atom of the dihydro-triazine ring. The six-membered dihydro-triazine that is fused with the benzimidazole ring system is relatively flat (r.

4-(4-Chloro-benz-yl)-5-methyl-2-phenyl-1H-pyrazol-3(2H)-one.

The five-membered ring of the title compound, C(17)H(15)ClN(2)O, is almost planar (r.m.s.