Preparation method of optically pure chiral 2-chloromandelic acid

Abstract

The invention provides a preparation method of optically pure 2-chloromandelic acid, which comprises the following steps: A) adding a chiral resolving agent, 2-chloromandelic acid and metallic compound into a solvent, dissolving by heating, cooling while stirring, carrying out vacuum filtration after a solid precipitates, drying and collecting the solid, wherein the mol ratio of chiral resolving agent to 2-chloromandelic acid is 1:4-2:1, and the mol ratio of metallic ion to 2-chloromandelic acid in the metallic compound is 1:4-2:1; and B) after recrystallizing the solid obtained in the step A), regulating the pH value to 1-2 with an acid solution, carrying out vacuum filtration to recycle the undissolved substance, extracting the mother solution with an organic solvent, drying, and carrying out spin drying to obtain the optically pure 2-chloromandelic acid product. The technique is simple and convenient, the raw materials and the resolving agent are innoxious and accessible, and the resolving agent can be recycled, thereby lowering the preparation cost and being green and economical. Meanwhile, the method is beneficial to implementing industrial mass production, and can satisfy the demands of people.

Description

technical field

[0001] The invention belongs to the field of organic synthesis, in particular, the invention relates to a preparation method of chiral o-chloromandelic acid. Background technique

[0002] O-chloromandelic acid, also known as α-hydroxy o-chlorophenylacetic acid (2-chloromandelic acid), molecular formula C 8 h 7 o 3 Cl, with a relative molecular mass of 186.5, has two enantiomeric configurations of R-type and S-type, and is widely used in many fields such as pharmaceutical production and chemical intermediates. Among them, (R)-o-chloromandelic acid can synthesize a new type of safe and efficient anti-platelet aggregation drug clopidogrel (clopidogrel), so it has a broad market. The chemical name of clopidogrel is (+)-(S)-α-(2-chlorophenyl)-6,7-dihydrothieno[3,2-c]pyridine-5(4H)-methyl acetate , clinically used to prevent myocardial infarction, stroke or atherosclerosis in patients with a history of peripheral arterial disease, the effect is good. In 2008, ...

Examples

Embodiment 1

[0026] Weigh 2.35 grams of O, O'-dibenzoyl-D-tartaric acid, 0.35 grams of calcium oxide and 1.165 grams of o-chloromandelic acid into a 100 mL round bottom bottle, add 80 mL of methanol, heat and reflux for a while, and the solution appears slightly In a mixed state, after reflux for one hour, after standing or stirring to cool to room temperature, filter, and dry to obtain 2.25 grams of white powdery solid——O, O'-dibenzoyl-D-tartaric acid of (R)-o-chloromandelic acid Calcium salts. The optical purity is 66.56%ee, and the yield is 58.21%.

Embodiment 2

[0028]Weigh 2.62 g of O, O'-di-p-methoxybenzoyl-D-tartaric acid, 0.425 g of alumina and 1.14 g of o-chloromandelic acid into a 100 mL round bottom bottle, add 65 mL of ethanol, and heat to reflux for a while , the solution was in a slightly mixed state. After reflux for one hour, after standing or stirring to cool to room temperature, filter, and dry to obtain 2.34 grams of white powdery solid——O, O'-di-p-methoxy of (R)-o-chloromandelic acid Aluminum benzoyl-D-tartrate. The optical purity is 70.03%ee, and the yield is 55.91%.

Embodiment 3

[0030] Weigh 2.51 g of O, O'-di-p-methylbenzoyl-D-tartaric acid, 0.35 g of calcium oxide and 1.18 g of o-chloromandelic acid into a 100 mL round bottom bottle, add 60 mL of water, heat to dissolve, and reflux for a Hour. After standing or stirring to cool to room temperature, filter and dry to obtain 2.11 g of white powdery solid—O, O'-di-p-toluyl-D-tartrate calcium salt of (R)-o-chloromandelic acid. The optical purity is 70.68%ee, and the yield is 52.23%.

technical field

[0001] The invention belongs to the field of organic synthesis, in particular, the invention relates to a preparation method of chiral o-chloromandelic acid. Background technique

[0002] O-chloromandelic acid, also known as α-hydroxy o-chlorophenylacetic acid (2-chloromandelic acid), molecular formula C 8 h 7 o 3 Cl, with a relative molecular mass of 186.5, has two enantiomeric configurations of R-type and S-type, and is widely used in many fields such as pharmaceutical production and chemical intermediates. Among them, (R)-o-chloromandelic acid can synthesize a new type of safe and efficient anti-platelet aggregation drug clopidogrel (clopidogrel), so it has a broad market. The chemical name of clopidogrel is (+)-(S)-α-(2-chlorophenyl)-6,7-dihydrothieno[3,2-c]pyridine-5(4H)-methyl acetate , clinically used to prevent myocardial infarction, stroke or atherosclerosis in patients with a history of peripheral arterial disease, the effect is good. In 2008, ...

Examples

Embodiment 1

[0026] Weigh 2.35 grams of O, O'-dibenzoyl-D-tartaric acid, 0.35 grams of calcium oxide and 1.165 grams of o-chloromandelic acid into a 100 mL round bottom bottle, add 80 mL of methanol, heat and reflux for a while, and the solution appears slightly In a mixed state, after reflux for one hour, after standing or stirring to cool to room temperature, filter, and dry to obtain 2.25 grams of white powdery solid——O, O'-dibenzoyl-D-tartaric acid of (R)-o-chloromandelic acid Calcium salts. The optical purity is 66.56%ee, and the yield is 58.21%.

Embodiment 2

[0028]Weigh 2.62 g of O, O'-di-p-methoxybenzoyl-D-tartaric acid, 0.425 g of alumina and 1.14 g of o-chloromandelic acid into a 100 mL round bottom bottle, add 65 mL of ethanol, and heat to reflux for a while , the solution was in a slightly mixed state. After reflux for one hour, after standing or stirring to cool to room temperature, filter, and dry to obtain 2.34 grams of white powdery solid——O, O'-di-p-methoxy of (R)-o-chloromandelic acid Aluminum benzoyl-D-tartrate. The optical purity is 70.03%ee, and the yield is 55.91%.

Embodiment 3

[0030] Weigh 2.51 g of O, O'-di-p-methylbenzoyl-D-tartaric acid, 0.35 g of calcium oxide and 1.18 g of o-chloromandelic acid into a 100 mL round bottom bottle, add 60 mL of water, heat to dissolve, and reflux for a Hour. After standing or stirring to cool to room temperature, filter and dry to obtain 2.11 g of white powdery solid—O, O'-di-p-toluyl-D-tartrate calcium salt of (R)-o-chloromandelic acid. The optical purity is 70.68%ee, and the yield is 52.23%.