An enantioselective synthesis of (1S,2S)-pseudoephedrine
摘要:
Synthesis of (1S, 2S)-pseudoephedrine is described via reduction of an alanine-derived oxazolidinone followed by treating with phenyl magnesium bromide and chemoselective N-methylation in an efficient and practical manner. (C) 2000 Elsevier Science Ltd. All rights reserved.
作者:Jingjun Yin、Mark A. Huffman、Karen M. Conrad、Joseph D. Armstrong
DOI:10.1021/jo052121t
日期:2006.1.1
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
THE separation of diastereoisomeric amino-alcohols is of importance as they have very different pharmacological properties. Hitherto fractional crystallization has been used as the only suitable method for this purpose ; however, sometimes, for example, in separating nor-ephedrine from nor-Ï-ephedrine1, it proved to be unsatisfactory.
Synthesis of (1S, 2S)-pseudoephedrine is described via reduction of an alanine-derived oxazolidinone followed by treating with phenyl magnesium bromide and chemoselective N-methylation in an efficient and practical manner. (C) 2000 Elsevier Science Ltd. All rights reserved.