Process for the preparation of (1R,3R)- and (1S,3S)-2,2-dihalo-3-(substituted phenyl)cyclopropanecarboxylic acids
AssigneeDow AgroSciences LLC
InventorsNakyen Choy, Fangzheng Li
Life of this patent
Estimating the term…
Abstract
The (1R,3R)- or (1S,3S)-enantiomer of 2,2-dichloro-3-(substituted phenyl)cyclopropane-carboxylic acid is prepared in a process involving chemical resolution of a racemic mixture of a trans-2,2-dichloro-3-(substituted phenyl)cyclopropanecarboxylic acid with an enantiomeric amine, isolation of a diastereomeric amine salt and finally treatment of the salt with an acid.
Claims10
A process for the preparation of a (1R,3R)- or a (1S,3S)-2,2-dihalo-3-(substituted phenyl)cyclopropanecarboxylic acid of Formula 1-2A or Formula 1-2B
- wherein:
- (A) R1 is selected from the group consisting of H, F, Cl, Br, I, CN, NO2, SF5, (C1-C3)alkyl, and (C1-C3)haloalkyl;
- (B) R2 is selected from the group consisting of H, F, Cl, Br, I, CN, NO2, SF5, (C1-C3)alkyl, and (C1-C3)haloalkyl;
- (C) R3 is selected from the group consisting of H, F, Cl, Br, I, CN, NO2, SF5, (C1-C3)alkyl, and (C1-C3)haloalkyl;
- (D) R4 is selected from the group consisting of H, F, Cl, Br, I, CN, NO2, SF5, (C1-C3)alkyl, and (C1-C3)haloalkyl;
- (E) R5 is selected from the group consisting of H, F, Cl, Br, I, CN, NO2, SF5, (C1-C3)alkyl, and (C1-C3)haloalkyl;
- and
- (G) X2 is selected from the group consisting of F, Cl, Br, and I;
- comprising:
- a) treating a racemic mixture of a trans-2,2-dihalo-3-(substituted phenyl)cyclopropane-carboxylic acid of Formula 1-1
- with an enantiomeric amine of Formula 2-1 or 2-2
- wherein:
- X1 is selected from the group consisting of C1-C4 alkyl and benzyl;
- to form a mixture;
- b) isolating a diastereomeric amine salt of Formula 3-1A or Formula 3-1B,
- or of Formula 3-2A or Formula 3-2B,
- from the mixture;
- and
- c) treating the isolated diastereomeric amine salt of Formula 3-1A or 3-1B, or of Formula 3-2A or 3-2B, with an acid to provide the (1R,3R)- or the (1S,3S)-2,2-dihalo-3-(substituted phenyl)cyclopropanecarboxylic acid of Formula 1-2A or Formula 1-2B.
A process for the preparation of a (1R,3R)-2,2-dichloro-3-(3-trifluoromethyl-4-fluorophenyl)cyclopropanecarboxylic acid of Formula 4-1
- comprising:
- a) treating a racemic mixture of trans-2,2-dichloro-3-(3-trifluoromethyl-4-fluorophenyl)cyclopropane-carboxylic acid of Formula 4-2
- with an enantiomeric amine of Formula 2-2A
- to form a mixture;
- b) isolating a diastereomeric amine salt of Formula 4-3
- from the mixture;
- and
- c) treating the isolated diastereomeric amine salt of Formula 4-3 with an acid to provide the (1R,3R)-2,2-dichloro-3-(3-trifluoromethyl-4-fluorophenyl)cyclopropanecarboxylic acid of Formula 4-1.
Dependencies are inferred from the claim text.