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Method for preparing chiral (S)-2-propionic acid

A chloropropionic acid and chiral technology, applied in the field of preparation of chiral chloropropionic acid, can solve problems such as high product cost, waste of water sources, pollution, etc., and achieve the advantages of improving market competitiveness, reducing production costs, and improving industrialization prospects. Effect

Inactive Publication Date: 2012-02-08
上海科利生物医药有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The second is that the reaction produces a large amount of dilute hydrochloric acid wastewater; although the neutralized pH value reaches neutrality, the wastewater has a high salt content and is difficult to treat. It can only be diluted with a large amount of tap water and discharged, resulting in serious water waste and pollution.
However, due to the high price of D-lactate methyl ester, the product cost is high, so there is no market competitiveness

Method used

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  • Method for preparing chiral (S)-2-propionic acid
  • Method for preparing chiral (S)-2-propionic acid
  • Method for preparing chiral (S)-2-propionic acid

Examples

Experimental program
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Effect test

Embodiment 1

[0038]

[0039] Resolution of (S)-2-chloropropionic acid: 118.5 grams of 2-chloropropionic acid (1mol) was added to 1000 milliliters of absolute ethanol, and under stirring, 116.1 grams of (R)-N-benzyl-phenethylamine was added dropwise (0.55mol) mixed with 200ml ethanol, drop it within 1 hour, then heat it to reflux within 1 hour, keep it under reflux for 30 minutes; then cool it down to room temperature naturally, then turn it to an ice-water bath to cool at 0-5°C, and keep it at this temperature for 5 At this time, a large amount of (R)-2-chloropropionic acid · (R)-N-benzyl-phenethylamine salt was precipitated; filtered, and the filter cake was washed with a small amount of ice ethanol; the filtrate was collected, and the ethanol was distilled under reduced pressure to dryness. (S)-2-chloropropionic acid was distilled under high vacuum by the oil change pump to obtain 48.6 grams of product (S)-2-chloropropionic acid. Analytical detection of chemical purity: 99.45% (GC), c...

Embodiment 2

[0041]

[0042]Racemization reclaims 2-chloropropionic acid: filter cake (R)-2-chloropropionic acid · (R)-N-benzyl-phenethylamine salt (approximately 200 grams of wet product) in Example 1 is added to 600ml In isopropanol, pass through dry hydrogen chloride gas until the pH value is 2~3, and (R)-2-chloropropionic acid is freed; at this time, a large amount of (R)-N-benzyl-phenethylamine hydrochloride precipitates Precipitate, filter, and wash the filtrate with a small amount of isopropanol; heat the filtrate to reflux, sample and analyze until no optical activity is detected; after distilling isopropanol under reduced pressure, continue to distill about 55.3 grams of 2-chloropropionic acid by raising the temperature. The 2-chloropropionic acid recovered by racemization can be separated and recycled next time.

Embodiment 3

[0044]

[0045] Reclaim resolution reagent (R)-N-benzyl-phenethylamine: filter cake (R)-N-benzyl-phenethylamine hydrochloride (about 146 grams of wet product) in embodiment 2 is added 500ml di In methyl chloride, add 25 grams of caustic soda in batches to pH 12-14; filter, wash the filter cake with a small amount of dichloromethane, and distill the filtrate under reduced pressure to recover the dichloromethane solvent; high vacuum distillation (R)-N-benzyl- Phenylethylamine, about 103.8 grams. The reclaimed (R)-N-benzyl-phenethylamine can be recycled for next time resolution.

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Abstract

The invention relates to a method for preparing (S)-2-propionic acid. The method comprises the following step of: splitting racemized 2-propionic acid in an alcohol solvent by using chiral N-benzyl-phenylethylamine BPA (Bisphenol A) to obtain (S)-2-propionic acid. Due to the adoption of the preparation method disclosed by the invention, the problem of environmental pollution caused by an L-alanine method can be fully solved, all splitting reagents and (R)-2-propionic acid obtained by splitting are fully recycled after racemization, waste is not produced basically, environmental pollution is avoided, the aims of saving energy, protecting the environment, reducing emission and lowering emission are fulfilled, the production cost is greatly lowered, the market competitiveness of the product is improved, and good industrial prospect is achieved. The (S)-2-propionic acid obtained with the method has high chemical purity and high chiral purity.

Description

technical field [0001] The invention belongs to the field of preparation of chiral chloropropionic acid, in particular to a preparation method of chiral (S)-2-chloropropionic acid. Background technique [0002] (S)-2-Chloropropionic acid (English name: S-2-Propionic acid. S-CPA for short) is a key intermediate in the synthesis of many chiral aryloxy herbicides. For example, use (S)-2-chloropropionic acid to condense with hydroquinone to obtain (R)-2-(4-hydroxybenzyloxy)propionic acid. The latter undergoes a condensation reaction to prepare Clodinafop-propargyl, Haloxyfop-R-methyl, Quizalofop-P, Fluazifop, Propaquizafop, Cyhalofop butyl ester, Fenoxaprop-ethyl, etc. [0003] There are two main methods for preparing (S)-2-chloropropionic acid at present. [0004] 1. L-alanine method. [0005] The method is to use L-alanine as the starting material of the chiral source, in the aqueous solution of hydrochloric acid, dropwise add the sodium nitrite aqueous solution to carry o...

Claims

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Application Information

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IPC IPC(8): C07C53/19C07C51/50
CPCY02P20/582
Inventor 李海林王世运张爱强张建现詹平平陈林
Owner 上海科利生物医药有限公司
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