Preparation method of paddy field herbicide pyriminobac-methyl

A technology of pyriflubacin and organic solvents, applied in the field of agrochemicals, can solve problems such as the complex process of pyriflubacin, and achieve the effects of mild reaction, high yield and good purity

Inactive Publication Date: 2016-01-27
CHANGZHOU UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Solve the complex technical problems of the above three methods of preparing pyriflubac, this method is a clean process production technology, can produce pyriflubac herbicide in batches, and its preparation process is as follows:

Method used

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  • Preparation method of paddy field herbicide pyriminobac-methyl
  • Preparation method of paddy field herbicide pyriminobac-methyl

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0030] Example 1: Preparation of 2-acetyl-6-nitrobenzoic acid methyl ester

[0031] Add 2-acetyl-6-nitrobenzoic acid (52.4g, 0.25mol), methanol (500mL) and p-toluenesulfonic acid (1.2g, 10.0mmol) into a 1L reaction flask, and heat to reflux for 8h under stirring , after the reaction, methanol was distilled off under reduced pressure, and the residue was recrystallized twice from toluene, and dried to obtain light yellow solid methyl 2-acetyl-6-nitrobenzoate (50.1 g, yield 89.8%), melting point 75.2 -77.4°C,

[0032] 1 HNMR (300MHz, CDCl 3 )δ8.32(dd, J=8.3,1.0Hz,1H),8.12(dd,J=7.8,1.0Hz,1H),7.72(t,J=8.0Hz,1H),4.01(s,3H), 2.66(s,3H).

example 2

[0033] Example 2: Preparation of 2-acetyl-6-aminobenzoic acid methyl ester

[0034] Add 2-acetyl-6-nitrobenzyl ester (50.0g, 0.22mol), nickel-aluminum catalyst (5.0g) and ethyl acetate (500mL) prepared in Example 1 in a 1L autoclave, stirring Under the pressure of hydrogen gas, the pressure was 50 atm at room temperature (25 ℃) to react for 8 hours. After the reaction, the catalyst was recovered by filtration, the filtrate was concentrated to recover ethyl acetate, and the residue was recrystallized with methanol to obtain light yellow crystals, 2-acetyl-6- Methyl aminobenzoate (41.1g, yield 94.9%), melting point 137.5-139.2°C,

[0035] 1 HNMR (300MHz, CDCl 3 )δ7.25(dd, J=7.9,7.2Hz,1H),6.76(d,J=8.3Hz,1H),6.62(d,J=7.3Hz,1H),5.11(s,2H),3.83( s,3H), 2.45(s,2H).

example 3

[0036] Example 3: Preparation of 2-acetyl-6-hydroxybenzoic acid methyl ester

[0037] Add 2-acetyl-6-aminobenzoic acid ester (40.0g, 0.20mol) prepared in Example 2 and a sulfuric acid solution (300mL) with a solute mass fraction of 20% in a 1L reaction flask, cool to 0°C, Add 200 mL of sodium nitrite aqueous solution (containing 15.0 g of sodium nitrite, 0.22 mol) dropwise under stirring to prepare a diazonium salt solution for later use, and the time for dropping is 2 hours.

[0038] Add cyclohexane (400ml) and sulfuric acid solution (400mL) with a mass fraction of solute of 25% in a 2L reaction flask, heat to 85°C and add the above-mentioned diazonium salt solution dropwise therein for 1 hour. After the completion of the reaction, the reaction was continued for 4 hours. After the reaction was completed, it was cooled, extracted with cyclohexane (200ml*3), concentrated, and the residue was recrystallized with cyclohexane to obtain a light yellow solid methyl 2-acetyl-6-hydrox...

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Abstract

The invention belongs to the field of agricultural chemistry, and particularly relates to a preparation method of a safe and efficient broad-spectrum paddy field herbicide pyriminobac-methyl ((E)-pyriminobac-methyl). The method comprises the following steps: with 2-acetyl-6-nitrobenzoic acid as a raw material, carrying out esterification reaction under an acid catalyst to prepare the 2-acetyl-6-nitrobenzene methyl formate; carrying out hydrogenation reduction reaction under catalysis of Ni/Al to prepare 2-amino-6-acetylbenzene methyl formate; carrying out diazotization to prepare the 6-methyl acetylsalicylate; carrying out imidization on methoxyamine hydrochloride under basic catalysis to prepare a salicylic acid midbody 6-(1-(N-methoxy)ethyl) methyl salicylate; and finally carrying out condensation reaction on the 2-mesyl-4,6-dimethoxy pyrimidine to prepare the pyriminobac-methyl. The method is a clean production technique and is suitable for mass production.

Description

technical field [0001] The invention belongs to the field of agrochemicals, and in particular relates to a preparation method of a safe and efficient broad-spectrum paddy field herbicide pyriminobac-methyl ((E)-pyriminobac-methyl). Background technique [0002] Pyrimidine salicylic acid herbicides are another class of acetolactate synthase (ALS) inhibitors successfully developed in the 1990s, which can control a variety of refractory weeds in rice fields. , broad spectrum, high selectivity and environmental friendliness have attracted great attention. It is researched and developed on the basis of structure optimization of sulfonylurea herbicides. Its herbicidal spectrum and activity are superior to those of sulfonylurea herbicides. Disadvantages such as drug damage. At present, the main products are pyriflubacin, bisfluben, saflufenacil (the specific structural formula is as follows) and so on. Among them, pyrifluben has contact and systemic effects, and is mainly used t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D239/60
CPCC07D239/60
Inventor 徐德锋许星
Owner CHANGZHOU UNIV
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