3-Cyano-6-hydroxy-4-methyl-2-pyridone: two new pseudopolymorphs and two cocrystals with products of anin situnucleophilic aromatic substitution

Abstract

Four crystal structures of 3-cyano-6-hydroxy-4-methyl-2-pyridone (CMP),viz.the dimethyl sulfoxide monosolvate, C7H6N2O2·C2H6OS, (1), theN,N-dimethylacetamide monosolvate, C7H6N2O2·C4H9NO, (2), a cocrystal with 2-amino-4-dimethylamino-6-methylpyrimidine (as the salt 2-amino-4-dimethylamino-6-methylpyrimidin-1-ium 5-cyano-4-methyl-6-oxo-1,6-dihydropyridin-2-olate), C7H13N4+·C7H5N2O2−, (3), and a cocrystal withN,N-dimethylacetamide and 4,6-diamino-2-dimethylamino-1,3,5-triazine [as the solvated salt 2,6-diamino-4-dimethylamino-1,3,5-triazin-1-ium 5-cyano-4-methyl-6-oxo-1,6-dihydropyridin-2-olate–N,N-dimethylacetamide (1/1)], C5H11N6+·C7H5N2O2−·C4H9NO, (4), are reported. Solvates (1) and (2) both contain the hydroxy group in aparaposition with respect to the cyano group of CMP, acting as a hydrogen-bond donor and leading to rather similar packing motifs. In cocrystals (3) and (4), hydrolysis of the solvent molecules occurs and anin situnucleophilic aromatic substitution of a Cl atom with a dimethylamino group has taken place. Within all four structures, anR22(8) N—H...O hydrogen-bonding pattern is observed, connecting the CMP molecules, but the pattern differs depending on which O atom participates in the motif, either theorthoorparaO atom with respect to the cyano group. Solvents and coformers are attached to these arrangementsviasingle-point O—H...O interactions in (1) and (2) or by additionalR44(16) hydrogen-bonding patterns in (3) and (4). Since thein situnucleophilic aromatic substitution of the coformers occurs, the possible Watson–Crick C–G base-pair-like arrangement is inhibited, yet the cyano group of the CMP molecules participates in hydrogen bonds with their coformers, influencing the crystal packing to form chains.