3-(2-Chloroethyl)-2-methyl-4-oxo-4H-pyrido[1,2-a]pyrimidinium 2,4,6-trinitrophenolate

In the cation of the title salt, C11H12ClN2O+center dot C6H2N3O7-, the chloroethyl side chain is in a syn conformation, nearly orthogonal to the pyrimidine ring, with a dihedral angle of 78.9 (6)degrees between the plane of the chloroethyl chain and the pyrimidine ring. The dihedral angle between the fused rings is 4.3 (3)degrees. In the picrate anion, the benzene mean plane makes dihedral angles of 26.7 (1), 33.6 (2) and 5.3 (6)degrees with the two o-NO2 groups and the p-NO2 group, respectively. Extensive hydrogen-bond interactions occur between the cation-anion pair which help to establish the crystal packing. A three-center O center dot center dot center dot(H,H)-(N,C) acceptor hydrogen bond is observed between the phenolate O atom of the picrate anion and the amine and methyl groups of the cation. An N-H center dot center dot center dot(O,O) bifurcated hydrogen bond is observed between the amine group and two O atoms from the phenolate and o-NO2 groups.