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Chapter Three Recent Advances in the Total Synthesis of Amaryllidaceae Alkaloids

2001; Elsevier BV; Linguagem: Inglês

10.1016/s0735-8210(01)80017-0

0735-8210

Sundaresan Prabhakar, M. Regina Tavares,

Psychedelics and Drug Studies

This chapter reviews the completed syntheses, formal or otherwise, of Amaryllidaceae alkaloids reported during the decade 1968 to 1998. The chapter lists new alkaloids isolated during the same period, followed by the process of dealing with the biological activity associated with some of them. The various structural types that are encountered in alkaloids belonging to the Amaryllidaceae family can be conveniently classified, from the point of view of their basic skeleton. These structural types include biphenyl alkaloids; tricyclic alkaloids (phenanthridine and related alkaloids, narciclasine related alkaloids, Dibenzo[c,e]azocine alkaloids); and tetracyclic alkaloids (pyrrolophenanthridines and related alkaloids, lycorine and related alkaloids, galanthamine and related alkaloids, crinine and related alkaloids, and tazettine and related alkaloids). The recently isolated Amaryllidaceae originate in nature from condensation of two simple biogenetic precursors, namely tyramine (C6-C2-N unit) and isovanillin (C6-C1 unit) to the corresponding Schiff's base, followed by reduction to the substituted benzylamine. A vast majority of these new alkaloids fall into previously known structural types, with only minor variations noted in the nature of the nitrogen atom and the positions occupied by common substituents such as OH, OMe within each group.