Reaktionen von (?)-Ephedrin bzw. (+)-Norpseudoephedrin und Derivaten mit N,N-Dimethylacetamid-dimethylacetal und N,N,-Dimethylformamid-dimethylacetal

Summary The reactivity of (–)-ephedrine (2) and (+)-norpseudoephedrine (3) towards the amidacetals1 a/b has been studied. Both2 and3 were acetylated resp. formylated at first at the amino group. Nevertheless, derivatives of2 and3 possessing a trisubstituted amino group react with1 a in a 3.3] sigmatopic rearrangement toortho substituted dimethylcarbamoylmethyl derivatives. By subsequent reduction with lithiumaluminiumhydride the aromatic compounds8,13, and18 with two aminoethyl groups are easily available. In contrast to these results1 b did not furnish any rearrangement products.