2,4-dimethoxybenzoic acid and 2,5-dimethoxybenzoic acid.
The title compounds (both C(9)H(10)O(4)) have nearly planar structures, and the methyl and/or carboxylic acid groups lie out of the molecular plane, as dictated by steric interactions. 2,5-Dimethoxybenzoic acid (2,5-DMBA) forms an unusual intramolecular hydrogen bond between the carboxylic acid group and the O atom of the methoxy group in the 2-position [O.O = 2.547 (2) A and O-H.O = 154 (3) degrees ]. 2,4-DMBA forms a typical hydrogen-bond dimer with a neighboring molecule.
Barich
Dewey H
DH
Department of Pharmaceutical Chemistry, University of Kansas, 2095 Constant Ave, Lawrence, KS 66047, USA.
Zell
Mark T
MT
Powell
Douglas R
DR
Munson
Eric J
EJ