N-Monomethylierung des Tetrandrins

N-Monomethylation of Tetrandrine With methyl iodide, tetrandrine forms the isomeric tetrandrinium salts 2 and 3 at a ratio of 4 : 1. Pure 3 is obtained via N'-benzyl-N-methyltetrandrinium diiodide. Deviations from data reported in the literature are discussed.