Crystals of the title compound, are triclinic, a= 9·555(2), b= 11·639(3), c= 7·341(3)A, α= 90·75(10), β= 90·77(5), γ= 102·70(2)°, Z= 2, space group P. The structure was determined from diffractometer data by direct methods, and was refined by full-matrix least-squares techniques to R 0·076 for 1548 observed reflexions. The molecule contains two approximately planar sections, the ring system and the extended side-chain, at an angle of 79°. The configuration of the CC double bond in the side chain is trans, and bond lengths and angles are normal. The molecules are joined by one normal O–H ⋯ O hydrogen bond between carboxy-groups, and by one bifurcated hydrogen bond, which is partly intra- and partly inter-molecular.