| 摘要 |
<p>A process for preparing d-threo methyl ±- piperid-2-ylarylacetates of formula III:
wherein R 1 is aryl having 6 to 28 carbon atoms, comprising the steps of: reacting a pyridine having formula I:
wherein R 1 is aryl having 6 to 28 carbon atoms with hydrogen in an alkanoic acid having 1 to 10 carbon atoms and in the presence of a catalyst to provide a mixture of threo and erythro piperidine stereoisomers having formulas IIa-d: €ƒ€ƒ€ƒ
adding an alkyl alkanoate having 2 to 20 carbon atoms to said mixture, thereby precipitating alkanoate salts of said erythro stereoisomers preferentially with respect to alkanoate salts of said threo stereoisomers;
reacting said erythro alkanoate salts with aqueous base to form said erythro stereoisomers;
reacting said erythro stereoisomers with an acid resolving agent in an alkyl alcohol having 1 to 5 carbon atoms, thereby forming acid salts of said 1-erythro stereoisomers preferentially with respect to said d-erythro stereoisomers;
reacting said 1-erythro acid salts with aqueous base to form said 1-erythro piperidine;
reacting said 1-erythro piperidine with an alkali metal alkoxide having one to 10 carbon atoms in organic solvent, whereby forming said d-threo piperidine, and
converting said d-threo piperidine to said d-threo methyl ±- piperid -2- ylarylacetate.</p> |
