(Z)-Ethyl 2-hydroxy-4-oxo-4-(1,4,5,6,8-pentamethoxynaphthalen-2-yl)but-2-enoate

Abstract

The title compound, C21H24O9, crystallizes with two independent molecules in the asymmetric unit which are almost centrosymmetrically related to each other. The ethanoate group in one of the two molecules is disordered over two positions with a site-occupation factor of 0.880 (7) for the major occupied site. In the crystal, the 1,3-diketone group exists in the keto–enol isomeric form due to the stabilizing effect of the intramolecular O—H...O hydrogen bond present in this form. The compound packs as a layered structure in which C—H...π and C—H...O interactions are present within and between the layers.