Photoreactions of di-p-anisylidenefulgide (di-p-anisylidenesuccinic anhydride)

The title compound as synthesised is the trans,trans-isomer. It is converted photochemically in solution to the cis,trans- and cis,cis-isomers. Irradiation of crystals of the cis,trans-form leads back to the trans,trans-, whereas irradiation of solid cis,cis- gives rise to other products.