# US 5,684,168 A · .beta.-phenylisoserine-(2R,3S), salts, preparation and use thereof

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- Number: US 5,684,168 A
- Document ID: US5684168A
- Status: Granted
- Kind: A
- Application number: 08/419,965
- Filed: 1995-04-10
- Granted: 1997-11-04
- Earliest claimed: 1991-01-17
- Assignees: Rhone-Poulenc Rorer S.A.
- Inventors: Jean-Pierre Duchesne; Max Ferraro
- Web page: https://patentgrep.com/patent/US5684168A

## CPC

- C07C 229/34: the carbon skeleton containing six-membered aromatic rings
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS

## Abstract

.beta.-phenylisiserine-(2R,3S), salts and preparation thereof through the action of ammonia on .beta.-phenylglycidic-(2R,3R) acid and its use in the preparation of taxane derivatives of general formula: ##STR1## wherein R is hydrogen or --COCH.sub.3 ;and R.sub.1 is phenyl or --O--C(CH.sub.3).sub.3.

## Claims

### Claim 1

(2R,3S)-.beta.-Phenylisoserine or a salt thereof selected from alkali metal salts, alkaline earth metal salts and salts with nitrogenous bases.

### Claim 2

Process for preparing (2R,3S)-.beta.-phenylisoserine, optionally in salt form, comprising reacting ammonia with (2R,3R)-.beta.-phenylglycidic acid or one of its salts, and isolating (2R,3S)-.beta.-phenylisoserine optionally in salt form.

### Claim 3 (depends on 2)

Process according to claim 2, wherein from 10 to 100 moles of ammonia are used per mole of (2R,3R)-.beta.-phenylglycidic acid.

### Claim 4 (depends on 1)

Process according to claim 1, wherein the reaction is performed in water or in an organic solvent.

### Claim 5 (depends on 4)

Process according to claim 4, wherein the solvent is chosen from aliphatic alcohols containing 1 to 4 carbon atoms.

### Claim 6 (depends on 1)

Process according to claim 1, wherein the ammonium salt is chosen from ammonium chloride and ammonium hydrogen carbonate.

### Claim 7 (depends on 1)

Process according to claim 1, wherein one mole of ammonium salt is used per mole of (2R,3S)-.beta.-phenylglycidic acid employed.

### Claim 8 (depends on 2)

Process according to claim 2, wherein the reaction is performed at a temperature of between 0.degree. to 100.degree. C.

### Claim 9 (depends on 1)

Method for using the (2R,3S)-.beta.-phenylisoserine according to claim 1 for the preparation of taxanes of formula: ##STR5## in which R represents a hydrogen atom or an acetyl radical and R.sub.1 represents a phenyl or t-butoxy radical, comprising
reacting a benzoylating or t-butoxycarbonylating agent and then an agent for protection of the hydroxyl function with (2R,3S)-.beta.-phenylisoserine,
condensing the product obtained with baccatine III or 10-deacetylbaccatine III in which the hydroxyl functions at the 7- and, optionally, the 10-positions are protected, and then,
after replacing the groups protecting the hydroxyl functions with hydrogen atoms, isolating the product obtained.

### Claim 10

Process for preparing (2R,3S)-.beta.-phenylisoserine, optionally in salt form, comprising:
reacting ammonia with (2R,3R)-.beta.-phenylglycidic acid or one of its salts at a temperature of between 0.degree. to 100.degree. C.;
said reaction being performed in the presence of an ammonium salt, and with from 10 to 100 moles of ammonia being used per mole of (2R,3R)-.beta.-phenylglycidic acid or one of its salts; and
isolating (2R,3S)-.beta.-phenylisoserine optionally in salt form.