Crystal structure of 7,8-benzocoumarin-4-acetic acid

Abstract

The fused-ring system in the title compound [systematic name: 2-(2-oxo-2H-benzo[h]chromen-4-yl)acetic acid], C15H10O4, is almost planar (r.m.s. deviation = 0.031 Å) and the Car—C—C=O (ar = aromatic) torsion angle for the side chain is −134.4 (3)°. In the crystal, molecules are linked by O—H...O hydrogen bonds, generating [100] C(8) chains, where the acceptor atom is the exocyclic O atom of the fused-ring system. The packing is consolidated by a very weak C—H...O hydrogen bond to the same acceptor atom. Together, these interactions lead to undulating (001) layers in the crystal.

Keywords

• crystal structure
• coumarin
• acetic acid
• hydrogen bonding