“…H atropine labelled on the tropic acid moiety has been recently published. 9 Unfortunately, these methods are not suitable for our purpose for the following reasons: long multistep syntheses [2][3][4][5][6][7] or labelling on the tropic acid moiety. 3,9 Noratropine 3, the first intermediate needed, has been prepared in various ways: partial synthesis from nortropine, 10 demethylation of atropine by reaction with trichloroethyl chloroformate followed by treatment with zinc dust in acetic acid, 11 oxidative demethylation of atropine with potassium permanganate with low yield, 12,13 photochemical demethylation of atropine 14,15 and iron salt mediated Polonovski demethylation of atropine N-oxide.…”