37573-41-4Relevant academic research and scientific papers
Highly diastereoselective catalytic Meerwein-Ponndorf-Verley reductions
Yin, Jingjun,Huffman, Mark A.,Conrad, Karen M.,Armstrong III, Joseph D.
, p. 840 - 843 (2007/10/03)
Very practical synthesis of ephedrine analogues in high yields and enantiopurity was realized by a highly diastereoselective Meerwein-Ponndorf- Verley (MPV) reduction of protected α-amino aromatic ketones using catalytic aluminum isopropoxide. The high anti selectivity resulted from the chelation of the nitrogen anion to the aluminum. In contrast, high syn selectivity was obtained with α-alkoxy ketones and other compounds via Felkin-Ahn control.
Reactions of (-)-Ephedrine, (+)-Norpseudoephedrine and Derivatives with N,N-Dimethylacetamid-dimethylacetal and N,N-Dimethylformamid-dimethylacetal
Koehl, M,Spreitzer, H.,Fleischhacker, W.
, p. 911 - 918 (2007/10/02)
The reactivity of (-)-ephedrine (2) and (+)-norpseudoephedrine (3) towards the amid-acetals 1 a/b has been studied.Both 2 and 3 were acetylated resp. formylated at first at the amino group.Nevertheless, derivatives of 2 and 3 possessing a trisubstituted amino group react with 1 a in a sigmatropic rearrangement to ortho substituted dimethylcarbamoylmethyl derivatives.By subsequent reduction with lithiumaluminiumhydride the aromatic compounds 8, 13, and 18 with two aminoethyl groups are easily available.In contrast to these results 1 b did not furnish any rearrangement products. Keywords. (-)-Ephedrine; (+)-Norpseudoephedrine; N,N-Dimethylacetamid-dimethylacetal; N,N-Dimethylformamid-dimethylacetal; Sympathomimetic effects; Sigmatropic rearrangements.
