Process for the stereoselective preparation of phenylisoserine derivatives used in making taxols
First Claim
1. Process for the stereoselective preparation of phenylisoserine derivatives of formula ##STR7## in which R is a phenyl or tert-butoxy radical and R1 is a protecting group for the hydroxyl group, comprising treating benzylamine with an agent for introducing a benzoyl or t-butoxycarbonyl group to give the product of formula ##STR8## which, after double anionization, is reacted with acrolein to give the alcohol of formula ##STR9## in the form of a syn and anti mixture, from which the syn form:
- ##STR10## is separated, the hydroxyl group of said syn form is protected and the alcohol protected in this way is then oxidized to give the phenylisoserine derivative of formula (I) in the syn form, which is optionally separated into enantiomers.
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Abstract
A stereoselective process for preparing phenylisoserine derivatives is disclosed. Benzylamine is reacted with an agent for introducing a phenyl or a t-butoxycarbonyl group. The product undergoes double anionization and then is reacted with acrolein to provide a mixture of alcohol syn and anti diasteroisomers. The syn isomer is isolated by chromatography. Whereupon, the hydroxyl is protected and the product is oxidized to provide the phenylisoserine derivative.
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10 Claims
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1. Process for the stereoselective preparation of phenylisoserine derivatives of formula ##STR7## in which R is a phenyl or tert-butoxy radical and R1 is a protecting group for the hydroxyl group, comprising treating benzylamine with an agent for introducing a benzoyl or t-butoxycarbonyl group to give the product of formula ##STR8## which, after double anionization, is reacted with acrolein to give the alcohol of formula ##STR9## in the form of a syn and anti mixture, from which the syn form:
- ##STR10## is separated, the hydroxyl group of said syn form is protected and the alcohol protected in this way is then oxidized to give the phenylisoserine derivative of formula (I) in the syn form, which is optionally separated into enantiomers.
- View Dependent Claims (2, 3, 4, 6, 7, 8, 9, 10)
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5. Process for the preparation of baccatin III and 10-deacetylbaccatin III derivatives of formula ##STR11## in which R is a phenyl radical or a tert-butoxy radical and R2 is a hydrogen atom or an acetyl radical, comprising treating benzylamine with an agent for introducing a benzoyl or t-butoxycarbonyl group, to obtain the product of formula ##STR12## which, after double anionization, is reacted with acrolein to give the alcohol of the formula ##STR13## in the form of a syn and anti mixture, from which the syn form:
- ##STR14## is separated, the hydroxyl group of said syn form is protected and the alcohol protected in this way is then oxidized to give the phenylisoserine derivative of formula;
##STR15## in which R1 is a protecting group for the hydroxyl group, in the syn form, the enantiomers of which are optionally separated, and which is reacted with a taxane derivative of formula ##STR16## in which R3 is an acetyl radical or a protecting group for the hydroxyl group and R4 is a protecting group for the hydroxyl group, and then the product of formula (II) is isolated after replacing the protecting groups R1 and R4 with hydrogen atoms and optionally replacing R3 with a hydrogen atom.
- ##STR14## is separated, the hydroxyl group of said syn form is protected and the alcohol protected in this way is then oxidized to give the phenylisoserine derivative of formula;
Specification