Chapter 3 Simple Indolizidine Alkaloids

Abstract

This chapter discusses that indolizidine alkaloids possessing the 1-azabicyclo[4.3.0]nonane skeleton are widely distributed in nature and comprise a wide range of structural and stereochemical features. The chapter focuses on the chiral synthesis, which has mostly been accomplished on the isolation and structures of new alkaloids. Forage materials contaminated with fungus Rhizocronia legitminicola are responsible for a disease in ruminants known as black patch. The obvious symptom associated with ingestion of contaminated feed is excessive salivation, which is thought to be caused by the alkaloid slaframine. Biological studies on slaframine included a potentially important use of the alkaloid in deliberately altering ruminal fermentation to improve the efficiency of feed utilization, lactation, and growth in sheep and cattle, and the ability of slaframine to stimulate circulating concentrations of a growth hormone in broiler chicks has been also investigated. The chapter reviews that investigation of synthetic routes to the simple indolizidine alkaloids has been active. With increased interest in the pharmacological properties of indolizidines, it is expected that further methodologies will be developed.