A general, selective, high-yield N-demethylation procedure for tertiary amines by solid reagents in a convenient column chromatography-like setup.

[reaction: see text] A traditional preparative chromatographic column can be used to achieve quantitative N-demethylation of tertiary N-methylamines and alkaloids. The filling is the crucial part and is loaded with different solid reagents in three reaction zones. The parent compound is charged on the column, and the neat N-demethylated secondary amine leaves the column some minutes later.