Aconic acid and related compounds: I. Discussion of the structure of aconic acid

Abstract

To aconic acid, first described in literature by Kekulé, the structure of a β,γ‐butenolide was given by Fittig and Beer. In 1947 Campbell and Hunt put forward arguments for an α,β‐butenolide structure. These arguments were based on a new synthesis of the acid and a comparison of the U.V. absorption spectrum of aconic acid with those of mesaconic acid and itaconic acid. Close inspection of the properties of aconic acid shows however that Campbell and Hunt's synthesis of aconic acid is not proving for its structure. Moreover these authors drew their spectral conclusions only from curveshapes, so we found it necessary to repeat the U.V. measurements at lower wave lengths. The rightness of the structure proposed by Campbell and Hunt could be proved.