Aplysinopsin-type alkaloids from Dendrophyllia sp., a scleractinian coral of the family dendrophylliidae of the philippines, facile photochemical (Z/E) photoisomerization and thermal reversal

✍ Scribed by Graziano Guella; Ines Mancini; Helmut Zibrowius; Francesco Pietra

• Publisher: John Wiley and Sons
• Year: 1989
• Tongue: German
• Weight: 433 KB
• Volume: 72
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.19890720703

✦ Synopsis

1. Introduction. -Since aplysinopsin (1) was first isolated from the sponge Aplysinopsis reticulata (Dictyoceratida) of the Great Barrier Reef [ 11, a number of related indole alkaloids have been found in other marine organisms. Such compounds can be classified into four structural types, represented by aplysinopsin itself (1) [ 11, 3'-deimino-3'-oxoaplysinopsin (2), isolated from the dendrophylliid coral Tubastraea sp. collected at Palawan, Philippines [2], 3'-deimino-2',4'-didemethyl-3'-oxoaplysinopsin (3), isolated from the Mediterranean dendrophylliid Leptopsammia pruvoti [2], and finally, 2'demethylaplysinopsin (4), and the 6-bromo analogue 5, isolated from the sponge Dercitus sp. (Choristida) collected in Belize waters [3].

We have recently reported that the ( E / Z ) configuration of compounds of the structural type 1-3 can be assigned on the basis of a larger H-C(8),C(5') 'H,13C heteronuclear H H 1 R=Me,Y=NH,(€/Z)>95:5b) 2 R = Me, Y = 0, (E/Z) > 95:sb) 3 R = H, Y = 0, (z/E) > 95:5b) ") Arbitrary numbering. b, Natural isomer ratio.

') On the basis of previous limited data concerning formation of compounds 1-3, kinetic control of the product distribution was assumed [2]; it is now clear that this is not the case.