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Preparation method of halosulfuron methyl

A technology of chlorpyrifosulfuron and pyrimidine amine, which is applied in the field of herbicide preparation, can solve the problems of difficulty in obtaining, high cost of raw materials, long process route, etc., and achieves the effects of mild reaction conditions, reduced production cost, and easy availability of raw materials

Active Publication Date: 2013-09-25
江苏省农用激素工程技术研究中心有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantages of this method are: (1) the starting material 1-methyl-4-pyrazole carboxylic acid methyl ester is not industrially produced and is not easy to obtain; (2) the chlorination reaction has more by-products 5-chloro- Methyl 1-methyl-4-pyrazolecarboxylate is produced with a low yield; (3) The mercaptolation reaction produces highly toxic gas hydrogen sulfide, which pollutes the environment; (4) The raw material for the condensation reaction is 4,6-dimethyl Oxy-2-pyrimidine phenyl carbamate is expensive; (5) the entire process route is long, the yield is low, and the cost of raw materials is high, so it is not suitable for industrial production

Method used

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  • Preparation method of halosulfuron methyl
  • Preparation method of halosulfuron methyl

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1）

[0016] The preparation method of the chlorpyrazosulfuron-methyl of the present embodiment is as follows:

[0017] ①Add 24g of ethyl 1-methyl-5-sulfonamido-4-pyrazolecarboxylate (98wt%, 0.1mol) and 150g of 10wt% sodium hydroxide aqueous solution into a 250mL four-neck flask. After the addition, the temperature was raised to 100°C for 5 hours.

[0018] After the reaction, cool to 20°C, add concentrated hydrochloric acid dropwise until the pH of the reaction system is less than 2, a white solid precipitates, cool in an ice-water bath to 5°C, filter with suction, wash the filter cake with water and dry to obtain 20.5g of white powder 1-Methyl-5-sulfonamido-4-pyrazolecarboxylic acid as solid, yield 99%, purity 99% (HPLC).

[0019] ②Add 100mL of methanol and 20.5g of 1-methyl-5-sulfonamido-4-pyrazolecarboxylic acid (99%, 0.099mol) prepared in step ① into a 250mL four-neck flask, stir to dissolve, and cool in an ice-water bath When the temperature is below 10°C, add 24g of thionyl ...

Embodiment 2～ Embodiment 5）

[0027] The rest of each embodiment is the same as Embodiment 1, except for step ①, see Table 1 for details.

[0028] Table 1

[0029]

Sodium hydroxide aqueous solution concentration

Hydrolysis reaction temperature

Product A weight

yield

Example 1

10wt%

100℃

20.5g

99%

Example 2

5wt%

100℃

18.6g

90%

Example 3

30wt%

100℃

19.0g

92%

Example 4

10wt%

40℃

15.5g

75%

Example 5

10wt%

60℃

17.6g

85%

[0030] .

[0031] In Table 1, Product A is 1-methyl-5-sulfonamido-4-pyrazolecarboxylic acid.

[0032] It can be seen from Table 1 that:

[0033] Under other conditions being the same, the yield of 10wt% sodium hydroxide aqueous solution is higher.

[0034] Under other conditions being the same, the yield is higher when the hydrolysis reaction temperature is 100°C.

Embodiment 6～ Embodiment 9）

[0036] The rest of each embodiment is the same as embodiment 1, the difference lies in step ②, see Table 2 for details.

[0037] Table 2

[0038]

Methylation reagent

Methylation reaction temperature

Product B weight

yield

Example 1

Thionyl chloride

65℃

21.0g

95%

Example 6

Dimethyl Sulfate

65℃

19.9g

90%

Example 7

Dimethyl carbonate

65℃

17.7g

80%

Example 8

Thionyl chloride

40℃

18.8g

85%

Example 9

Thionyl chloride

100℃

17.6g

80%

[0039] .

[0040] In Table 2, Product B is methyl 1-methyl-5-sulfonamido-4-pyrazolecarboxylate.

[0041] It can be seen from Table 2:

[0042] Under other conditions being the same, using thionyl chloride as the methylation reagent, the yield is higher.

[0043] Under other conditions being the same, the methylation reaction temperature was 65°C and the yield was higher.

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Abstract

The invention discloses a preparation method of halosulfuron methyl. 1-methyl-5-sulfonylamino-4-pyrazole ethyl formate is taken as a raw material, and the halosulfuron methyl is obtained by hydrolysis reaction, methylation reaction, chlorination reaction, acylation reaction and condensation reaction; and 4, 6-dimethoxy-2-pyrimidinamine is adopted as the raw material for the condensation reaction. The method disclosed by the invention has the advantages of easiness in getting the raw material, simplicity in operation, higher yield and lower cost, and is suitable for industrial production.

Description

technical field [0001] The invention relates to a preparation method of a herbicide, in particular to a preparation method of chlorpyrazosulfuron-methyl. Background technique [0002] Clopyrazosulfuron-methyl is a new type of sulfonylurea herbicide. It has low toxicity and wide application. It can be mixed with other herbicides to form a variety of preparations, and it can also be formulated into 25% wettable powder, 50% Wettable powder, 75% water dispersible granules. Clopyrazosulfuron-methyl can be widely used in the removal of weeds in wheat, corn, rice, sugarcane, lawn and other crops. [0003] "Journal of Heterocyclic Chemistry" 1997, Volume 34, No. 2, No. 537-540, discloses a preparation method of clopyrazosulfuron-methyl, which starts with methyl 1-methyl-4-pyrazolecarboxylate The starting material is obtained through chlorination reaction, mercaptolation reaction, sulfonyl chloride reaction, and amination reaction to obtain chloropyrazine sulfonamide (that is, 3-ch...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D403/12
Inventor 王智敏孔繁蕾杨斌
Owner 江苏省农用激素工程技术研究中心有限公司
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