4-[2-(o-carboxybenzamido)ethyl]phenoxyacetic acid dihydrate

C18H17NO6.2H2O, Mr = 379.386, monoclinic, P21/c, a = 7.161 (5), b = 12.997 (2), c = 20.290 (3) A, beta = 99.22 (2) degrees, V = 1861.4 A3, Z = 4, Dx = 1.354 g cm-3, Cu K alpha radiation, lambda = 1.5418 A, mu = 9.2 cm-1, F(000) = 800, T = 293 K, final R(F) = 0.051 for 2262 observed reflections. The structure was solved by direct methods and compared to the previously determined structure of the analogous drug molecule, bezafibrate. The structural characteristics of the two compounds are then correlated to their relative activities as allosteric effectors of hemoglobin. The molecule adopts a synplanar-antiplanar conformation unlike other phenoxyacetic acids.