Topochemistry. Part XVI. The crystal structure of trans-β-2-furylacrylic acid

Abstract

The crystal structure of trans-β-2-furylacrylic acid has been determined from the photographically recorded h0l and h1l intensities. The nearly planar molecules are pairwise hydrogen bonded at the carboxyl groups (O⋯O: 2·64 Å); these pairs are arranged in stacks in which parallel [graphic omitted] groups make contact of 3·84 Å. Interstack contacts of exocyclic [graphic omitted] groups are nowhere shorter than 4·5 Å.

The contact along the b axis is assumed to be responsible for the photochemical formation of the dimer of symmetry m(β-truxinic acid analogue). Ultraviolet-light-induced polymerisation may occur along a reaction path involving the exocyclic [graphic omitted] groups and double bonds of the furan ring.