| abstract |
ABSTRACT There are disclosed a process for producing (-)-5-(R)-1-hydroxy-2-[(R)-1-methyl-3-phenylpropyl amino-ethyl salicylamide and its acid addition salts in high yields which does not require chromatography, and impor-tant intermediates in this process. The process is stereoselective for the desired (R,R) amine; a preferred embodiment includes the steps of (1) reaction of an N-[(R)-protected]-(R)-1-methyl-3-phenyl-propylamine with a 4-0-protected 2-bromo-3-carbamoyl-ace-tophenone to produce the corresponding R,R-glycyl-benza-mide, (2) reduction to produce a mixture of S,R,R;R,R,R--hydroxybenzamides, (3) removal of the protecting groups, (4) resolution of the deprotected product and, if de-sired, conversion to the free R,R -amine or to another salt. In this process, the selection of particular N-pro-tecting groups has a very favourable effect, especially in steps (2) and (3). |