[Studies on the biotransformation of reproterol. Structure determination of the main metabolite (author's transl)]

Biotransformation of 7-(3-[2-(3,5-dihydroxyphenyl)-2-hydroxy-ethylamino]-propyl)-theophylline (reproterol, Bronchospasmin), a beta 2-adrenergic drug recently introduced into therapeutic use, leads to the same main metabolite in animals and in man. By mass-spectroscopy and by synthesis its structure was shown to be tetrahydroisoquinoline derivative which is produced from reproterol by uptake of an additional carbon atom concomitant with cyclization.