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+·C6H2N3O7 −, the chloroethyl side chain is in a syn conformation, nearly orthogonal to the pyrimidine ring, with a dihedral angle of 78.9 (6)° between the plane of the chloroethyl chain and the pyrimidine ring. The dihedral angle between the fused rings is 4.3 (3)°. In the picrate anion, the benzene mean plane makes dihedral angles of 26.7 (1), 33.6 (2) and 5.3 (6)° 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⋯(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⋯(O,O) bifurcated hydrogen bond is observed between the amine group and two O atoms from the phenolate and o-NO2 groups.