Methods for the synthesis of amines such as ephedrine and intermediates

摘要

A method for the preparation of a compound of formula (VI): in which RSUB2 /SUBis an optionally substituted C1-C6 alkyl; RSUB4 /SUBis H, OH, an optionally substituted C1-C6 alkyl or an optionally substituted C1-C6 alkoxy; RSUB5 /SUBis an optionally substituted aryl, an optionally substituted aralkyl, or an optionally substituted alkyl; and RSUB6 /SUBis H or an optionally substituted C1-C6 alkyl; the method including the step of subjecting a ketone of formula (V) in which RSUB2/SUB, RSUB4 /SUBand RSUB5 /SUBare as defined above, to reductive amination with an amine of formula RSUB3/SUBNHSUB2 /SUBin which RSUB3 /SUBis an optionally substituted alkyl, and a reductant to form the compound of formula (VI), wherein the reaction is conducted in the presence of a supercritical fluid or a liquefied gas.