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The preparation method of fine dimethenamid

A technology of refining dimethenamid and xylene, which is applied in the field of herbicides, can solve the problems of large-scale industrial production, and achieve the effects of simple operation, high yield and mild reaction conditions

Active Publication Date: 2022-03-01
NUTRICHEM LAB CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a new preparation method of refined xylenolamid in order to overcome the difficulty of large-scale industrial production in the prior art. The method has mild reaction conditions, high yield and easy operation, and is very suitable for for industrial production

Method used

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  • The preparation method of fine dimethenamid
  • The preparation method of fine dimethenamid
  • The preparation method of fine dimethenamid

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preparation example Construction

[0031] The invention provides a method for preparing refined dimethenamid, the method comprising the following steps,

[0032] 1) In the presence of an acid, the compound of the structure shown in formula (1) is subjected to a first contact reaction with (2S)-1-hydroxypropyl-2-amine to obtain the compound of the structure shown in formula (2);

[0033] 2) In the presence of the first base, the compound of the structure shown in formula (2) is subjected to a second contact reaction with a methyl etherification reagent to obtain the compound of the structure shown in formula (3);

[0034] 3) In the presence of the second base, the compound of the structure shown in formula (3) is subjected to the third contact reaction with chloroacetyl chloride to obtain refined dimethenamid,

[0035]

[0036] According to the present invention, the structure of the refined dimethenamid is shown in formula (4),

[0037]

[0038] According to the present invention, the first contact react...

Embodiment 1

[0065] 1) Preparation of (S)-2-[(2,4-dimethyl-3-thienyl)amino]-L-propanol

[0066] Add 10.4g content and be 98.5% by weight of 2,4-dimethyl-2,3-dihydrothiophen-3-one, 9.1g content of 99% by weight of L-alaninol ((2S) -1-hydroxypropyl-2-amine, ee value 99%) and 0.3g p-toluenesulfonic acid monohydrate, heated to boiling reaction (about 170°C). During the reaction, low boiling point substances (water) were distilled off. After 7 hours of reaction, the gas phase detection of 2,4-dimethyl-2,3-dihydrothiophen-3-one was less than 4%. Negative pressure removes the remaining L-alaninol (the internal temperature is up to 180°C, the top temperature is not more than 110°C, -96KPa, steaming until the top temperature drops indicates that the L-alaninol is exhausted). The residual viscous liquid in the remaining kettle was washed out with 50mL of dichloromethane, and then washed with 20ml of water. After layering, the solvent was removed to obtain 13.8g of the structural compound (dark visc...

Embodiment 2

[0082] 1) Preparation of (S)-2-[(2,4-dimethyl-3-thienyl)amino]-L-propanol

[0083] In the reaction flask, the content of adding 10.4g is 98.5% by weight of 2,4-dimethyl-2,3-dihydrothiophene-3-one, the content of 10g is 99% by weight of L-alaninol ((2S )-1-hydroxypropyl-2-amine, ee value 99%) and 0.8g p-toluenesulfonic acid, heated to boiling reaction (around 170°C). During the reaction, low boiling point substances (water) were distilled off. After 7 hours of reaction, the gas phase detection of 2,4-dimethyl-2,3-dihydrothiophen-3-one was less than 4%. Negative pressure removes the remaining L-alaninol (the internal temperature is up to 180°C, the top temperature is not more than 110°C, -96KPa, steaming until the top temperature drops indicates that the L-alaninol is exhausted). The residual viscous liquid in the remaining kettle was washed out with 50mL of dichloromethane, then washed with 20ml of water, and the solvent was removed after layering to obtain 13.6g of the struct...

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Abstract

The present invention relates to the field of herbicides, and discloses a preparation method of refined dimethenamid, the method comprising: 1) in the presence of an acid, making a compound of the structure shown in formula (1) and (2S)-1-hydroxy Propyl-2-amine carries out the first contact reaction, obtains the compound of structure shown in formula (2); 2) in the presence of the first base, make the compound of structure shown in formula (2) and methyl etherification reagent carry out the second Contact reaction to obtain the compound of the structure shown in formula (3); 3) in the presence of the second base, make the compound of the structure shown in the formula (3) and chloroacetyl chloride carry out the third contact reaction to obtain refined dimethenamid . According to the method of the invention, the reaction conditions are mild, the yield is high, the operation is simple and convenient, and it is very suitable for industrial preparation.

Description

technical field [0001] The invention relates to the field of herbicides, in particular to a preparation method of refined dimethenamid. Background technique [0002] Dimethenamid is a chloroacetamide herbicide that inhibits the synthesis of very long chain fatty acids. The mode of action is primarily as a soil treatment herbicide, but can also be applied post-emergence. Herbicides enter plants through root and hypocotyl uptake, have little or no foliar activity, and have little plant migration, used to control annual grasses and broadleaf crops such as corn, soybeans, sugar beets, potatoes, and legumes weeds. [0003] The synthesis of dimethenamid is mainly prepared by reacting 1-methoxy-2-propanamine disclosed in CN1023482C, CN85106474A and the like with tetrahydrothiophene-3-one or its analogues. Refined dimethenamid, which is the optical S body of dimethenamid, has a good market prospect in recent years. Its synthesis document is reported as US Patent No. 5,457,085A. ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D333/36
CPCC07D333/36
Inventor 吴浩杨海舰黄广英
Owner NUTRICHEM LAB CO LTD
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