Crystal structures of three 3,4,5-trimethoxybenzamide-based derivatives

Abstract

The crystal structures of three benzamide derivatives,viz. N-(6-hydroxyhexyl)-3,4,5-trimethoxybenzamide, C16H25NO5, (1),N-(6-anilinohexyl)-3,4,5-trimethoxybenzamide, C22H30N2O4, (2), andN-(6,6-diethoxyhexyl)-3,4,5-trimethoxybenzamide, C20H33NO6, (3), are described. These compounds differ only in the substituent at the end of the hexyl chain and the nature of these substituents determines the differences in hydrogen bonding between the molecules. In each molecule, them-methoxy substituents are virtually coplanar with the benzyl ring, while thep-methoxy substituent is almost perpendicular. The carbonyl O atom of the amide rotamer istransrelated with the amidic H atom. In each structure, the benzamide N—H donor group and O acceptor atoms link the molecules intoC(4) chains. In1, a terminal –OH group links the molecules into aC(3) chain and the combined effect of theC(4) andC(3) chains is a ribbon made up of screw relatedR22(17) rings in which the ...O—H... chain lies in the centre of the ribbon and the trimethoxybenzyl groups forms the edges. In2, the combination of the benzamideC(4) chain and the hydrogen bond formed by the terminal N—H group to an O atom of the 4-methoxy group link the molecules into a chain ofR22(17) rings. In3, the molecules are linked only byC(4) chains.