ChemInform Abstract: Aplysinopsin-Type Alkaloids from Dendrophyllia sp., a Scleractinian Coral of the Family Dendrophylliidae of the Philippines. Facile Photochemical (Z/E) Photoisomerization and Thermal Reversal

The dendrophylliid Dendrophyllia sp. of Palawan contains the indole alkaloids 2′-demethylaplysinopsin (4) and 2′-demethyl-3′-N-methylaplysinopsin (6) and their 6-bromo analogues in H (Z/E) ratio larger than 95:5; these mixtures undergo facile photoisomerization to give mixtures richer in the (E) stereoisomer which undergo thermal isomerization to give back the original mixtures.