Patent ID: 6509491
Filing Date: 2003-01-21
Classification: C07C

Abstract:
A process for the preparation of a phenylisoserine ester of the formula (II)&phgr;â€”CH(NHâ€”COâ€”R3)â€”CH(OH)â€”COâ€”Oâ€”R1 where R1 is C1-C5 alkyl with the proviso that R1 is not tertiary, where R3 is â€”Ch3 or â€”CH2â€”CH3 and the stereochemistry at C-2 is R and at C-3 is S, which comprises:(1) contacting a mixture of a cinnamate of the formula (I) &phgr;â€”CH&boxH;CHâ€”COâ€”Oâ€”R1 where the double bond is in the trans configuration and R1 is as defined above, osmium in one of its oxidation states, cinchona alkaloid or derivative thereof, either N-bromoacetamide, or N-bromopropionamide, a non-nitrogen base, water, a solvent in which the cinnamate is at least partially soluble, in the presence of a compound of the formula R2â€”COâ€”NH2 where R2 is C1-C6 alkyl with the proviso that R2 is not tertiary.