Gomes Ligia R, Low John Nicolson, Wardell James L, Pinheiro Alessandra C, de Mendonça Thais C N, de Souza Marcus V N
REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, 687, P-4169-007 Porto, Portugal.
Acta Crystallogr C. 2013 Mar;69(Pt 3):293-8. doi: 10.1107/S0108270113004344. Epub 2013 Feb 16.
The molecular conformations of three N-alkyl-2-(methylsulfanyl)nicotinamide derivatives, namely N-cyclohexyl-2-(methylsulfanyl)nicotinamide, C13H18N2OS, (I), N-isopropyl-2-(methylsulfanyl)nicotinamide, C10H14N2OS, (II), in which there are two molecules in the asymmetric unit which were chosen to form a hydrogen-bonded pair, and N-(2-hydroxyethyl)-2-(methylsulfanyl)nicotinamide dihydrate, C9H12N2O2S·2H2O, (III), are compared with those of four unsubstituted N-alkylnicotinamide compounds. The substituted compounds show a higher degree of torsion of the pyridine ring with respect to the amide group than do the unsubstituted compounds, with dihedral angles in the range 40-60° for the former and 20-35° for the latter. In (I) and (II), the supramolecular structure is defined by amide-N to carbonyl-O chains. In (III), the nicotinamide molecules are linked by hydrogen bonds to two water molecules resulting in two linked chains of rings which form the three-dimensional network.
比较了三种N-烷基-2-(甲基硫烷基)烟酰胺衍生物，即N-环己基-2-(甲基硫烷基)烟酰胺，C13H18N2OS，(I)；N-异丙基-2-(甲基硫烷基)烟酰胺，C10H14N2OS，(II)（其中不对称单元中有两个分子，它们被选择形成氢键对）以及N-(2-羟乙基)-2-(甲基硫烷基)烟酰胺二水合物，C9H12N2O2S·2H2O，(III)的分子构象与四种未取代的N-烷基烟酰胺化合物的分子构象。与未取代的化合物相比，取代化合物中吡啶环相对于酰胺基团的扭转程度更高，前者的二面角在40 - 60°范围内，后者在20 - 35°范围内。在(I)和(II)中，超分子结构由酰胺-N到羰基-O链定义。在(III)中，烟酰胺分子通过氢键与两个水分子相连，形成两个相连的环链，构成三维网络。
