Simple Syntheses of 3-Substituted Indoles and their Application for High Yield 14C-Labelling

Abstract

Methods are described which allow the synthesis of several plant indole alkaloids and their metabolites at different scales. Compounds synthesized include gramine (1) (3-di-methylaminomethylindole) which is directly derived from indole, while its biosynthetic precursors 3-aminomethylindole (3) and 3-methylaminomethylindole (2) as well as indole-3-carboxylic acid (7) are synthesized via indole-3-aldehyde (6). Slight changes of the experimental conditions allow syntheses with high yields not only at the molar but also at the μmolar level. This is extremely useful when isotope labelled compounds of high specific radioactivity are required for studies of plant metabolism.