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

Article abstract of DOI:10.1002/hlca.19890720703

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 a (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.