Molecular and crystal structure of 2-cyano-(2E)-pentadien-2,4-oic acid and ethyl-2-cyano-(2E)-pentadien-2,4-oate

X-ray study of 2-cyano-(2E)-pentadien-2,4-oic acid (1) and its ethyl ester (2) showed that the molecules of1 and2 in the crystalline phase form stacks by translating along the shortest crystallographic axis. The nature of the intermolecular interactions favoring the formation of such β-structures was analyzed within the framework of the Bader topological theory. Possible routes of topochemical reactions of compounds1 and2 are considered. Dedicated to the memory of Academician M. I. Kabachnik on his 90th birthday. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1991–1995, October, 1998.