Synthesis of 2,4-Di(p-formyl)-α-truxillic Acid by Crystal Engineering

Abstract
P-Formycinnamic acid, which usually crystallizes in either the β-form or γ-form of packing, was converted into its diethyl acetal. The introduction of such bulky groups onto a benzene ring successfully provided us with the α-form of packing, from which the desired photodimer, 2,4-di(p-formyl)-α-truxillic acid (c-2, t-4-bis(p-formylphenyl)-r-1,t-3-cyclobutanedicarboxylic acid) was obtained with a yield of 85–90%.