Topramezone intermediate and topramezone preparation method

A technology of fenfentrazone and intermediates, applied in the field of organic synthesis, can solve the problems of increasing the difficulty of industrialization, difficulty in recycling, high price, etc., and achieve the effects of simplifying the process, reducing costs and high yield

Pending Publication Date: 2020-03-27
JIANGSU FLAG CHEM IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The reduction step of this method uses a noble metal palladium compound catalyst, which is expensive and difficult to recycle. It also uses flammable and explosive butyllithium reagents, which increases the difficulty of industrialization.

Method used

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  • Topramezone intermediate and topramezone preparation method
  • Topramezone intermediate and topramezone preparation method
  • Topramezone intermediate and topramezone preparation method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0050]

[0051] In a 250mL four-necked flask, 160g of chlorobenzene, 40g of 2,3-dimethyl anisole (molecular weight 152.26, 262.71mmol, 1eq), 0.35g of aluminum trichloride (molecular weight 133.34, 2.63mmol, 0.01eq), cool down to 5°C in an ice bath, drop 38.29g of sulfonyl chloride (molecular weight 134.97, 283.73mmol, 1.08eq) within 80 minutes, keep warm in an ice bath for one hour, after the reaction is complete, add 150g of saturated sodium bicarbonate The solution was washed once, then washed with 100g water for the first time, and the organic phase was spin-dried to obtain 48.5g of crude product, which was 2,3-dimethyl-4-methylthiochlorobenzene (molecular weight 186.7, theoretically obtained 49.05g). The rate is 98.88%.

[0052] ( 1 H-NMR (CDCl 3 )δ: 2.35(s,3H), 2.36(s,3H), 2.43(s,3H), 6.97~6.99(d,1H), 7.19~7.21(d,1H)).

[0053]

[0054] Add 48.5g 2,3-dimethyl-4-methylthiochlorobenzene (molecular weight 186.7, 259.78mmol, 1eq) and 1.71g sodium tungstate dihydrate ...

Embodiment 2

[0074] In a 1L four-necked flask, 250g of DCE and 83.33g of 2,3-dimethylanisole (molecular weight: 152.26, 0.574mol, 1eq) were sequentially added at room temperature, and stirred to dissolve. Maintain 20-25°C and start to add 87.07g of bromine (molecular weight 159.08, 0.574mol, 1eq) dropwise, and drop it for about 1 hour. After the dropwise addition was completed, the mixture was incubated and stirred at room temperature for one hour. The reaction solution was washed once with 60g water and 30g water successively, the organic phase was separated, and the solvent was evaporated to dryness under negative pressure to obtain 124.51g of crude product, which was 2,3-dimethyl-4-methylthiobromobenzene (molecular weight 231.15, theoretically obtained 126.51g), mass yield 98.42%.

[0075] ( 1 H-NMR (CDCl 3 )δ: 2.36(s,3H), 2.40(s,3H), 2.42(s,3H), 6.89~6.91(d,1H), 7.36~7.38(d,1H)).

[0076]

[0077] Add 249.02g acetic acid, 124.51g 2,3-dimethyl-4-methylthiobromobenzene (molecular ...

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Abstract

The invention relates to the field of organic synthesis, in particular to a topramezone intermediate and a topramezone preparation method. The topramezone preparation method comprises the following steps: 3-[3-halogen-2-methyl-6-(methylsulfonyl)phenyl]-4, 5-dihydroisoxazole and cyanide are subjected to a substitution reaction to obtain 3-[3-cyano-2-methyl-6-(methylsulfonyl)phenyl]-4, 5-dihydroisoxazole; hydrolysis reaction is performed on 3-[3-cyano-2-methyl-6-(methylsulfonyl)phenyl]-4, 5-dihydroisoxazole under the action of acid or alkali to obtain 2-methyl-3-(4, 5-dihydroisoxazole-3-yl)-4-methylsulfonyl benzoic acid; and 2-methyl-3-(4, 5-dihydroisoxazole-3-yl)-4-methylsulfonyl benzoic acid and 1-methyl-5-hydroxypyrazole are condensed and rearranged to generate topramezone. According to the topramezone intermediate and the topramezone preparation method provided by the invention, the use of an expensive palladium catalyst and a dangerous butyl lithium reagent is avoided, the yield isrelatively high, the cost is reduced, the process is simplified, the defects in the prior art are overcome, and the industrial value is achieved.

Description

technical field [0001] The invention relates to the field of organic synthesis, in particular to an intermediate of fenflumezone and a preparation method of fenflumezone. Background technique [0002] Topramezon (Topramezon) is the first benzopyrazolone herbicide developed by BASF. Conducted to the top and base to the meristem, by inhibiting the 4-hydroxyphenylpyruvate dioxygenase (4-HPPD) in the biosynthesis of plastoquinone, indirectly affecting the synthesis of carotenoids, thereby interfering with the synthesis of chloroplasts and function, eventually leading to severe bleaching. Sensitive weeds usually show whitish symptoms within 2 to 5 days after treatment, and the poisoning symptoms in the aboveground growth area (growing point, internode, leaf and leaf vein) are the most obvious, and the growth of weeds is inhibited at the same time. Under light, the chlorotic tissue is necrotic and the plants usually die after 14 days of treatment. It has a good control effect o...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D261/04C07D413/10
CPCC07D261/04C07D413/10
Inventor 张璞卜龙高鹋吴耀军骆文侯远昌
Owner JIANGSU FLAG CHEM IND
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