Three hexahydropyridopyrimidine-spiro-cyclohexanetriones: supramolecular structures generated by O—H…O, N—H…O, C—H…O and C—H… hydrogen bonds, and – stacking interactions
4′,4′-Dimethyl-2-methylsulfanyl-3,4,5,6,7,8-hexahydropyrido[2,3-d]pyrimidine-6-spiro-1′-cyclohexane-2′,4,6′-trione, C15H19N3O3S, (I), has a markedly polarized molecular–electronic structure, and the molecules are linked into a three-dimensional framework by a combination of N—H…O, C—H…O and C—H… hydrogen bonds. 8-Hydroxymethyl-4′,4′-dimethyl-2-methylsulfanyl-3,4,5,6,7,8-hexahydropyrido[2,3-d]pyrimidine-6-spiro-1′-cyclohexane-2′,4,6′-trione, C16H21N3O4S, (II), where the hydroxymethyl substituent is disordered over two sets of sites, has a much less polarized structure than (I); the molecules are linked by a combination of O—H…O and N—H…O hydrogen bonds into chains containing alternating (8) and (16) rings, and these chains are linked into sheets by a combination of a – stacking interaction and a C—H…O hydrogen bond. 8-Ethoxymethyl-2-methoxy-4′,4′-dimethyl-3,4,5,6,7,8-hexahydropyrido[2,3-d]pyrimidine-6-spiro-1′-cyclohexane-2′,4,6′-trione, C18H25N3O5, (III), has an unpolarized electronic structure, and a combination of N—H…O, C—H…O and C—H… hydrogen bonds links the molecules into sheets.
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Document Type: Research Article
Publication date: 01 June 2004