Aplysinopsin-type alkaloids fromDendrophyllia 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 facilephotoisomerization to give mixtures richer in the (E) stereoisomer which undergo thermal isomerization to give back the original mixtures.