The solid-state packing of chloro substituted 2-aminopyrimidines and the occurrence of N—H—CL hydrogen-bonding associations

The solid-state packing arrays of ten 4-chloro substituted 2-aminopyrimidines have been examined and the occurrence of N—H—Cl hydrogen-bonding associations in those structures discussed. The ten compounds were 4,6-dichloropyrimidine 1, 2-amino-4-chloro-6-(4-carbamoylpiperidinyl)pyrimidine hemihydrate 2, 2-amino-4-chloro-6-(4-fluorophenylthio)pyrimidine 3, 2-amino-4-chloro-6-(1-phenylethylamino)pyrimidine 4, 2-amino-4-chloro-6-benzylaminopyrimidine $\text{1}\text{6}$ hydrate 5, 2-amino-4-chloro-6-isopropylaminopyrimidine 6, 2-amino-4-chloro-6-(4-(2,3-dimethylphenyl)piperizino)pyrimidine hydrate 7, 2-amino-4,6-dichloro-5-phenylpyrimidine 8, 2-amino-4-chloro-6-dimethylamino-5-phenylpyrimidine 9 and 2-amino-4-chloro-5-phenyl-6-thiomorpholinopyrimidine 10. The single-crystal x-ray structures of 1–4 have been previously reported while the structures of 5–10 are presented in this paper. All packing motifs, except compound 2, exhibit characteristic R₂²(8) hydrogen-bonded 2-aminopyrimidine dimers, to varying degrees of polymerisation. Only compounds 8 and 9 include N—H—Cl interactions, which for compound 8 is a three-center association in addition to a N—H—N interaction.