Chapter 9 The Steroid Alkaloids: The Salamandra Group

Abstract

This chapter presents an overview of the steroid alkaloids of the Salamandra group. The main alkaloid of maculosa taeniata is samandarine, a saturated secondary amine, C 19 H 31 NO 2 , with a secondary hydroxy group. Chromic acid oxidation converts it to the corresponding ketone, samandarone. The second oxygen atom is present as an ether bridge and there are two C-methyl groups. These data together with the molecular formula show that samandarine contains three rings. This chapter discusses about Hofmann degradation of N -methylsamandarine methiodide, which yields a desbase that contains all of the carbon atoms, thus proving that the nitrogen atom of samandarine belongs to a ring. The double bond of the desbase can be hydrogenated to yield the dihydro-desbase. The desbase is stable to alkali but on warming with dilute sulfuric acid, it adds 1 mole of water, forming the oxydihydro-desbase and thus indicating that it is an enolether. In this chapter, isolation and purification of different Salamandra alkaloids is described. Structure of alkaloids with an oxazolidine system is discussed. Alkaloids with a carbinolamine system are elaborated. Biosynthesis and toxicology of Salamandra alkaloids is also described.