The chemistry of conjugated polyenoic acids in sulphuric acid: a homologous series of retinoic acid (vitamin A acid)
Abstract
Homologues of retinoic acid are converted by acid-catalysed cyclization into hydrindene compounds bearing a non-conjugated (αβ-saturated) enoic acid (or lactone) side-chain. Explanations are given for the colour reaction including structural elucidation of the quenched products and their mechanism of formation.