Method for preparing a mixture of stereoisomers of .alpha.-cyano-3-phenoxybenzyl isovalerate ester derivatives having a higher insecticidal and acaricidal activity
AssigneeSumitomo Chemical Company, Limited
InventorsYukio Suzuki, Masahiro Hayashi, Kenzi Takuma
Life of this patent
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Abstract
A method for preparing a mixture of stereoisomers of .alpha.-cyano-3-phenoxybenzyl isovalerate ester derivatives, which is rich is an enantiomer pair of a compound having an (S)-configuration on both the acid and alcohol moieties and an enantiomer thereof having an (R)-configuration on both the acid and alcohol moieties.
Claims34
A method for preparing a mixture of stereoisomers of .alpha.-cyano-3-phenoxybenzyl isovalerate ester derivatives of the formula:
- ##STR2## wherein X is a hydrogen atom or a fluorine atom, and * indicates an asymmetric carbon atom, which mixture is rich in a Y-isomer which is an enantiomer pair of a compound of said formula, one enantiomer having an (S)-configuration on both the acid and alcohol moieties and the enantiomer thereof having an (R)-configuration on both the acid and alcohol moieties, which method comprises removing crystals of a compound of said formula rich in an X-isomer which is an enantiomer pair of a compound of said formula, one enantiomer having an (S)-configuration on the acid moiety and an (R)-configuration on the alcohol moiety and the enantiomer thereof having an (R)-configuration on the acid moiety and an (S)-configuration on the alcohol moiety, from a mother liquor containing an ester of said formula which is a mixture of said X-isomer and said Y-isomer to obtain a mixture rich in said Y-isomer.
A crystalline-form mixture of stereo-isomers of .alpha.-cyano-3-phenoxybenzyl isovalerate ester derivatives of the formula:
- ##STR3## wherein X is a hydrogen atom or a fluorine atom, and * indicates an asymmetric carbon atom, which contains at least 60% of an enantiomer pair of a compound of said formula, one enantiomer having an (S)-configuration on the acid moiety and an (R)-configuration on the alcohol moiety and the enantiomer thereof having an (R)-configuration on the acid moiety and an (S)-configuration on the alcohol moiety.
A crystalline-form enantiomer pair of stereoisomers of a .alpha.-cyano-3-phenoxybenzyl isovalerate ester derivatives of the formula:
- ##STR4## wherein X is a hydrogen atom or a fluorine atom, and * indicates an asymmetric carbon atom, which comprises an enantiomer pair of a compound of said formula, one enantiomer having an (S)-configuration on the acid moiety and an (R)-configuration on the alcohol moiety and the enantiomer thereof having an (R)-configuration on the acid moiety and an (S)-configuration on the alcohol moiety, substantially free of other stereoisomers of said ester derivative.
A method for preparation of a mixture of stereoisomers of .alpha.-cyano-3-phenoxybenzyl isovalerate ester derivatives of the formula:
- ##STR5## wherein X is a hydrogen atom of a fluorine atom, and * indicates an asymmetric carbon atom, which mixture is rich in a Y-isomer which is an enantiomer pair of a compound of said formula, one enantiomer having an (S)-configuration on both the acid and alcohol moieties and the enantiomer thereof having an (R)-configuration on both the acid and alcohol moieties, which method comprises partially dissolving a solidified mixture of said Y-isomer and an X-isomer which is an enantiomer pair of a compound of said formula having an (S)-configuration on the acid moiety and an (R)-configuration on the alcohol moiety and an enantiomer thereof having an (R)-configuration on the acid moiety and an (S)-configuration on the alcohol moiety in a solvent which preferentially dissolves said Y-isomer and then removing the remaining solid to obtain a solution rich in said Y-isomer.
A method for preparation of a mixture of stereoisomers .alpha.-cyano-3-phenoxybenzyl isovalerate ester derivatives of the formula:
- ##STR6## wherein X is a hydrogen atom or a fluorine atom, and * indicates an asymmetric carbon atom, which mixture is rich in a Y-isomer which is an enantiomer pair of a compound of said formula, one enantiomer having an (S)-configuration on both the acid and alcohol moieties and the enantiomer thereof having an (R)-configuration on both the acid and alcohol moieties which method comprises the steps of:
- (a) removing crystals of a compound of said formula rich in an X-isomer which is an enantiomer pair of a compound of said formula, one enantiomer having an (S)-configuration on the acid moiety and an (R)-configuration on the alcohol moiety and the enantiomer thereof having an (R)-configuration on the acid moiety and an (S)-configuration on the alcohol moiety, from a mother liquor containing an ester of said formula which is a mixture of said X-isomer and said Y-isomer to obtain a mixture rich in said Y-isomer;
- (b) separating said crystals of X-isomer from said mixture rich in said Y-isomer;
- (c) bringing said separated X-isomer into contact with a basic catalyst to induce epimerization thereof to produce a mixture of X-isomer and Y-isomer;
- and
- (d) recycling the mixture of X-isomer and Y-isomer obtained in step (c) to the mother liquor of step (a).
Dependencies are inferred from the claim text.