Chapter 2 The Tropane Alkaloids

Abstract

Publisher Summary This chapter presents information on tropane alkaloids. Hyoscyamine is the naturally occurring, optically active form of tropine tropate, while atropine is the racemic form. The name scopolamine seems generally accepted as being synonymous with hyoscine, both referring to the l -enantiomer. The dl -form is called atroscine. “Total synthesis of scopolamine” described it as a racemic substance. In 1971, the first report of isolation of a tropane alkaloid from the family Proteaceae marked the beginning of a flurry of activity in this area. Some drastically different types of substituents on the tropane skeleton have been encountered and the first apparent racemic mixtures of naturally occurring, unsymmetrical tropane skeletons have been isolated. Bellendine, the first alkaloid to be isolated from the Proteaceae, has been shown to be 2,3-(2,3-tropeno)-5-methyl-γ-pyrone. Esters identified were the acetate, propionate (a new natural ester), isobutyrate, butyrate (new), -methylbutyrate or isovalerate (not differentiated), benzoate, and 1,2-dithiolane-3-carboxylate (the major component, a new alkaloid called brugine). A relationship has been demonstrated between protein synthesis and alkaloid synthesis in root cultures of D. stramonium var. tatula. One of the first properties observed about cocaine was its ability to produce the numbness of the tongue. Dipole moment, nuclear magnetic resonance (NMR), temperature-dependent NMR studies, and qualitative considerations of van der Waals interactions provided data on the conformation of atropine.