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

The solid-state packing arrays of eight 4-sulfur substituted 2-aminopyrimidines have been examined and the occurrence of N–H—S hydrogen-bonding associations in those structures discussed. The eight compounds were 2,5-diamino-4-mercapto-6-methylpyrimidine 1, 2-amino-4,6-bis(phenylthio)pyrimidine 2, 2-amino-4,6-bis(4-chlorophenylthio)pyrimidine 3, 2-amino-4,6-bis(4-methylphenylthio)pyrimidine 4, 5 (two polymorphs), 2-amino-4-chloro-6-(4-fluorophenylthio)pyrimidine 6, 2-amino-4-(4-chlorophenylthio)-6-morpholinopyrimidine 7, 2-amino-4-(4-(2,3-dimethylphenyl)piperizino)-6-phenylthiopyrimidine 8, and 2-amino-4-(4-(2-ethoxyphenyl)piperizino)-6-(4-chlorophenylthio)pyrimidine 9. The single-crystal x-ray structures of 1 – 3 have been previously reported while the structures of 4 – 9 are presented in this paper. All packing motifs exhibit characteristic R₂²(8) hydrogen-bonded 2-aminopyrimidine dimers, to varying degrees of polymerisation, whereas compounds 1 – 5 and 7 include N–H—S associations, the majority of which are three-center associations with an included N–H—N interaction.