Concerning the identity test for caffeine in the pharmacopoeia - Part 1: Imidazo[1,5-a]pyrimidinium salts

Since the edition of the DAB 9 a specific reaction is proposed as identity test for caffeine. According to the literature, at first a hydrolysis to ca ffeidine occurs with following reaction to the enaminone of acetylacetone. Model experiments however show, that this species is not existing under the stated conditions. instead, with anellation, a condensation product of the imidazo[1,5-a]pyrimidine type occurs. This may be the precursor of the dye .