Claims
- 1. A process for preparing an S-isomer of a compound of the formula
- wherein R.sub.1 is a straight or branched alkyl of from 1 to 6 carbon atoms, phenyl, or cycloalkyl having from 3 to 6 carbon atoms; R.sub.2 is hydrogen, methyl, or carboxyl; individual enantiomers thereof; and pharmaceutically acceptable salts thereof; with the proviso that when R.sub.2 is hydrogen, R.sub.1 is other than methyl; said process comprising the steps of forming an acid chloride of an acid of the formula HOC(.dbd.O)CH(R.sub.1)(R.sub.2), the corresponding acid chloride having the formula ClC(.dbd.O)CH(R.sub.1)(R.sub.2), adding the acid chloride to a solution of (4R,5S)-(+)-4-methyl-5-phenyl-2-oxazolidinone and n-butyllithium at -78.degree. C. under argon to produce an oxazolidinone derivative of the formula ##STR9## treating the oxazolidinone (II) with benzyl .alpha.-bromoacetate to produce an ester ##STR10## treating the ester (III) with hydrogen peroxide and lithium oxide followed by treatment with sodium metabisulfite to produce a compound of the formula ##STR11## treating the compound (IV) with borane dimethyl sulfide complex to produce the compound ##STR12## forming the corresponding tosylate from the compound (V), forming an azide from the corresponding tosoylate and reducing the azide to the amine of the formula ##STR13## wherein R.sub.1 and R.sub.2 have the meanings defined for formula (I), Ph is phenyl, Me is methyl, and Bn is benzyl.
CROSS-REFERENCE TO RELATED APPLICATIONS
This is a divisional of application Ser. No. 08/064,285, filed on May 18, 1993, abandoned, which is a continuation-in-part of application Ser. No. 07/886,080, filed May 20, 1992, abandoned; which is a continuation-in-part of 07/618,692, filed Nov. 27, 1990, abandoned.
US Referenced Citations (5)
Foreign Referenced Citations (1)
Number |
Date |
Country |
49-40460 |
Nov 1974 |
JPX |
Non-Patent Literature Citations (6)
Entry |
Pollini, Synthesis, pp. 44-45 (1975). |
Ono, Synthesis, pp. 226-227 (1984). |
Rathke, J. Am. Chem. Soc., 92. pp. 3222-3223 (1970). |
Carson, J. Org. Chem., 20, pp. 1591-1601 (1955). |
Colonge, Bull. Soc. Chim. Fr., pp. 598-603 (1962). |
Andruszkiewicz, Synthesis, pp. 953-955 (1989, received by PTO Jan. 18, 1990). |
Divisions (1)
|
Number |
Date |
Country |
Parent |
64285 |
May 1993 |
|
Continuation in Parts (2)
|
Number |
Date |
Country |
Parent |
886080 |
May 1992 |
|
Parent |
618692 |
Nov 1990 |
|