The Structure of the Alkaloid Peduncularine. Communication no. 172 on organic natural products

Synthesis of Aristoquinoline Enantiomers and Their Evaluation at the α3β4 Nicotinic Acetylcholine Receptor

The first synthesis of aristoquinoline (1), a naturally occurring nicotinic acetylcholine receptor (nAChR) antagonist, was accomplished using two different approaches. Comparison of the synthetic material's spectroscopic data to that of the isolated alkaloid identified a previously misassigned stereogenic center. An evaluation of each enantiomer's activity at the α3β4 nAChR revealed that (+)-1 is significantly more potent than (-)-1. This unexpected finding suggests that naturally occurring 1 possesses the opposite absolute configuration from indole-containing Aristotelia alkaloids.

Natural Products Isolated from Endemic Tasmanian Vascular Plants

Tasmania is the south-eastern island state of Australia. It is geographically isolated and is recognised for both its rich diversity of plant species and high degree of endemism. Although 530 endemic Tasmanian vascular plant species are known, natural products have only been isolated from 27 of these species (~5.1 %), representing 3 classes (Dicotyledonae, Monocotyledonae, and Gymnospermae), 12 families, and 14 genera. Terpenoids, flavonoids, and alkaloids are the major classes of compound that have been isolated from these species. This report provides the first review of the natural products isolated from endemic Tasmanian plant species and covers ~70 years of research in this area.

Pseudosymmetry in Azabicyclo[2.1.1]hexanes. A Stereoselective Construction of the Bicyclic Core of Peduncularine

Intramolecular photocycloaddition of 41 or its equivalent leads to the formation of photoadduct 25. While retro-Mannich fragmentation of the "b" bond in 25 leads to the formation of 44 (via 43), with the incorrect relative stereochemistry for the synthesis of peduncularine 5, selective fragmentation of the "a" bond in 25 leads to the formation of 42 (via 26) with the correct relative stereochemistry for the synthesis of 5.

Simple indole alkaloids and those with a non-rearranged monoterpenoid unit

This review covers newly isolated simple indole alkaloids, structure determinations, total syntheses and biological activities reported in the literature in 2003.