Crystal Structure Determination of N-(para-Chlorophenyl) Phthalimide and Analysis of its Formation from N-(para-Chlorophenyl) Phthalanilic Acid

Abstract

Crystalline N-(para-chlorophenyl) phthalanilic acid undergoes a topochemical cyclization reaction with the elimination of water yielding crystalline N-(para-chlorophenyl) phthalimide. The crystal structure of the imide product has been determined and compared to the previously determined structure of the reactant. The reaction from this particular crystalline phase of N-(para-chlorophenyl) phthalanilic acid is enhanced by the presence of a high energy molecular conformer of the acid, little molecular motion necessary for reaction, and only a minor rearrangement required to pack into the imide structure after the reaction. A detailed molecular mechanism for this reaction is proposed involving some bond rotation, but little movement of the molecule as a whole.