3- aryl-8-hydroxy-3,4-dihydroisocoumarins: Synthesis of aglycones of macrophyllosides A,B and C.

Abstract

A facile, aluminium chloride mediated, one-step conversion of 7 - methoxy - 3 - benzylphthalides (6a-d) into 3 - aryl - 8 - hydroxy - 3 , 4 - dihydroisocoumarins (7a-d) is described. The 7 - methoxy - 3 - benzylphthalides (6a-d) are prepared from phthalides (2& and b) via the intermediacy ofhydroxyphthalides (4a-d) and 3 - benzylidenephthalides (5a-e).[PhSeSePhr are found to effect stereoselective oxyselenylation of I,n- dioletins (I) leading to a novel methodology to the synthesis of a,a' -trans-dialkyl cyclic ethers (8). Keywords: Photosensitized electron transfer (PET), episelenonium radical cation, oxyselenylation, a,a' -trans-dialkyl cyclic ethers.been subjected to some kind of chemical or biological examination; thus vast majority of natural wealth remains unexplored. Studies on marine natural products initiated only recently have yielded molecules with exotic molecular architecture and diverse bioactivity. Well-directed research on natural products will enrich our bioresource base. In the current millennium, India is in a pre-eminent position to contribute towards natural product research with the utilization of its rich knowledge base and biodiversity.