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Synthesis method of (S)-metolachlor

A technology of metolachlor and a synthesis method, which is applied in the field of chemical synthesis of pesticides, can solve the problems of high price, high production cost, solid waste and the like, and achieves the effects of good stereoselectivity, mild reaction conditions and good atom economy.

Inactive Publication Date: 2015-04-01
HEFEI UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The biggest difficulty of method (1) is the preparation of split enzymes, which is difficult to realize industrialization; the advantage of method (2) is that no chiral resolution is required in the reaction process, which greatly reduces the cost, but due to the use of D-lactic acid as a raw material, the price is expensive , the production cost is high, and there are also problems such as acylation selectivity, introduction of leaving groups and waste solids, and the total yield is only 50%.
The technical difficulty of method (3) is the asymmetric catalytic hydrogenation reaction of imines. The core technology is the synthesis of chiral catalysts, which are unstable and expensive.

Method used

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  • Synthesis method of (S)-metolachlor
  • Synthesis method of (S)-metolachlor
  • Synthesis method of (S)-metolachlor

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] 1) Under the protection of nitrogen, add 6.2g (0.06mol) of L-lactate methyl ester and 30mL ether to the three-necked flask, and slowly add 2.74g (0.02mol) of phosphorus trichloride to the three-necked flask under ice bath conditions, Control the rate of addition so that the reaction temperature is not higher than 5°C. After the dropwise addition, react at 0°C for 2 hours, then raise the temperature to 25°C for 2 hours, monitor the end point of the reaction by TLC, add saturated aqueous sodium carbonate solution to the reaction solution, separate Organic phase, the aqueous layer was extracted 3 times with ether, combined organic phase, washed three times with water, anhydrous MgSO 4 Drying, column chromatography separation (eluent is a mixed solution of ethyl acetate and petroleum ether, volume ratio 1:10) to obtain intermediate I—(R)-2-methyl chloropropionate 6.8g, yield 92.9g %, the ee value is 98%.

[0029] 1 HNMR (400MHz, CDCl 3 ,δ): 4.13(q,1H); 3.18(s,3H); 1.16(d...

Embodiment 2

[0039] 1) Under the protection of nitrogen, add 6.2g (0.06mol) of L-methyl lactate and 30mL of diethyl ether to the three-necked flask, and slowly add 5.4g (0.02mol) of phosphorus tribromide to the three-necked flask under ice bath conditions, Control the rate of addition so that the reaction temperature is not higher than 5°C. After the dropwise addition, react at 0°C for 2 hours, then raise the temperature to 25°C for 2 hours, monitor the end point of the reaction by TLC, add saturated aqueous sodium carbonate solution to the reaction solution, separate Organic phase, the aqueous layer was extracted 3 times with ether, combined organic phase, washed three times with water, anhydrous MgSO 4 Drying, separation by column chromatography (eluent is a mixed solution of ethyl acetate and petroleum ether, volume ratio 1:10) to obtain intermediate I—(R)-2-methyl bromopropionate 9.5g, yield 94.8 %, the ee value is 97.6%.

[0040] 1 H NMR (400 MHz, CDCl 3 ,δ): 4.39 (m, 1H), 3.80 (s,...

Embodiment 3

[0048] 1) Under the protection of nitrogen, add 6.2g (0.06mol) of L-lactate methyl ester and 30mL ether to the three-necked flask, and slowly add 4.11g (0.03mol) of phosphorus trichloride to the three-necked flask under ice bath conditions, Control the rate of addition so that the reaction temperature is not higher than 5°C. After the dropwise addition, react at 0°C for 2 hours, then raise the temperature to 25°C for 2 hours, monitor the end point of the reaction by TLC, add saturated aqueous sodium carbonate solution to the reaction solution, separate Organic phase, the aqueous layer was extracted 3 times with ether, combined organic phase, washed three times with water, anhydrous MgSO 4 Drying, column chromatography separation (eluent is a mixed solution of ethyl acetate and petroleum ether, volume ratio 1:10) to obtain intermediate I—(R)-2-methyl chloropropionate 6.6g, yield 95.7 %, the ee value is 98.0%.

[0049] Step 2) to step 5) were the same as in Example 1, and 4.96 ...

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Abstract

The invention discloses a synthesis method of (S)-metolachlor. The synthesis method of (S)-metolachlor comprises the following steps of: firstly, halogenating L-lactate with alcohol to invert the configuration of chiral carbon, wherein L-lactate serves as the raw material; then reducing ester, etherifying alcohol, and carrying out nucleophilic substitution reaction with 2-methyl-6-ethyl aniline to generate secondary amine; and finally enabling the secondary amine to react with chloroacetyl chloride to generate (S)-metolachlor. Compared with the prior synthesis route, the synthesis method disclosed by the invention has the characteristics of good atom economy, low cost, good stereoselectivity and mild reaction conditions. In addition, the starting raw materials are low in cost and are easily available.

Description

1. Technical field [0001] The invention relates to a method for preparing a known compound, in particular to a method for synthesizing (S)-metolachlor, and relates to the technical field of chemical synthesis of pesticides. 2. Background technology [0002] In 1952, the Monsanto Company of the United States discovered that chloroacetamide compounds had herbicidal activity, and then alachlor and metolachlor became typical representatives of amide herbicides, among which metolachlor was the most important herbicide in the United States and North America. The highly selective amide herbicide used in the largest amount in other places, its chemical name is 2-ethyl-6-methyl-N-(l'-methyl-2'-methoxyethyl) chloroacetanilide, which has There are two configurations of R and S, and only the S-isomer is the active substance, which has the herbicidal effect. (S)-metolachlor is also known as Jinduer or refined metolachlor. Studies have shown that under the same dosage, the activity of (S...

Claims

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Application Information

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IPC IPC(8): C07C233/88C07C231/02
Inventor 李有桂卢梦梦王振宇甘吉福朱成峰
Owner HEFEI UNIV OF TECH