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Preparation method of 2,2,7-trifluoro-2H-1,4-benzoxazine-3(4H)-ketone compound

A technology of -2H-1 and ketone compounds, applied in the direction of organic chemistry, can solve the problems of low product yield, expensive raw materials, poor safety, etc., and achieve the effect of high product yield, safe raw materials, and easy industrialization

Active Publication Date: 2014-07-30
NUTRICHEM LAB CO LTD
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Problems solved by technology

[0010] The object of the present invention is to provide a kind of preparation method of 2,2,7-trifluoro-2H-1,4-benzoxazin-3(4H)-ketone compound, this method overcomes existing preparation 2, In the method of 2,7-trifluoro-2H-1,4-benzoxazin-3(4H)-ketones, the raw materials are expensive and poor in safety, and the product yield is low.

Method used

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  • Preparation method of 2,2,7-trifluoro-2H-1,4-benzoxazine-3(4H)-ketone compound
  • Preparation method of 2,2,7-trifluoro-2H-1,4-benzoxazine-3(4H)-ketone compound
  • Preparation method of 2,2,7-trifluoro-2H-1,4-benzoxazine-3(4H)-ketone compound

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preparation example Construction

[0025] The present invention provides a preparation method of 2,2,7-trifluoro-2H-1,4-benzoxazin-3(4H)-one compound represented by formula (I), the method comprising the following steps:

[0026] (1) The 7-fluoro-2H-1,4-benzoxazin-3(4H)-one compound represented by formula (III) is chlorinated with a chlorination reagent in the first reaction medium to generate 2,2-dichloro-7-fluoro-2H-1,4-benzoxazin-3(4H)-one compounds represented by formula (II);

[0027] (2) Chlorine-fluorine exchange of 2,2-dichloro-7-fluoro-2H-1,4-benzoxazin-3(4H)-one compounds represented by formula (II) with fluorinating reagents reaction;

[0028]

[0029] in,

[0030] R 1 Selected from hydrogen, C1-C6 alkyl, C1-C6 haloalkyl, C3-C6 cycloalkyl, C3-C6 allyl, C3-C6 haloallyl, C3-C6 propargyl, C3-C6 halo Any one of propargyl, C1-C6 alkoxy, benzyl, methylsulfonyl and N,N-dialkylmethylsulfonyl;

[0031] R 2 Any one selected from hydrogen, nitro, amino, cyano, isothiocyano, hydrazino and heterocycles c...

Embodiment 1

[0058] This example is used to illustrate the preparation method of 2,2,7-trifluoro-2H-1,4-benzoxazin-3(4H)-one.

[0059] (1) Chlorine gas (7.23 g, 102mmol); and then recover phosphorus trichloride by atmospheric distillation to obtain 11.32g reddish-brown liquid, GC / MS m / e(M+)=234.96, showing that the liquid contains 99% of 2,2-dichloro-7- Fluoro-2H-1,4-benzoxazin-3(4H)-one (structure shown in the following formula).

[0060]

[0061] Take a small amount of reddish-brown liquid, add carbon tetrachloride to the reddish-brown liquid, cool down, let it stand, and precipitate crystals for NMR (nuclear magnetic resonance) test. The NMR result is: 1H-NMR (500MHz, DMSO-d6): δ (ppm)=2.90(br,1H).

[0062] (2) Add the reddish-brown liquid obtained in step (1) dropwise into a solution of pyridinium hydrofluoride (27.92g, 100mmol), then stir at 50°C for 4 hours, and extract with ethyl acetate (extract three times, each 30 mL of ethyl acetate); the combined organic phases were washe...

Embodiment 2

[0067] This example is used to illustrate the preparation method of 2,2,7-trifluoro-6-nitro-2H-1,4-benzoxazin-3(4H)-one.

[0068] (1) Add 6-nitro-7-fluoro-2H-1,4-benzoxazin-3(4H)-one (10.61g, 49mmol) to phosphorus trichloride (42g) suspension at room temperature Chlorine gas (7.23g, 102mmol) was introduced; then phosphorus trichloride was recovered by atmospheric distillation to obtain 13.21g reddish-brown liquid, GC / MS m / e(M+)=279.95, showing that the liquid contained 99% of 2,2- Dichloro-6-nitro-7-fluoro-2H-1,4-benzoxazin-3(4H)-one (structure shown in the following formula).

[0069]

[0070] Take a small amount of reddish-brown liquid, add ethyl acetate to the reddish-brown liquid, cool down, let it stand, and precipitate crystals for NMR testing. The NMR result is: 1H-NMR (500MHz, DMSO-d6): δ(ppm)=2.90 (br,1H).

[0071] (2) Add the reddish-brown liquid obtained in step (1) dropwise into a solution of pyridinium hydrofluoride (27.92g, 100mmol), then stir at 20°C for 2 ...

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Abstract

The invention discloses a preparation method of a 2,2,7-trifluoro-2H-1,4-benzoxazine-3(4H)-ketone compound, which comprises the following steps: (1) performing a chlorination reaction of a 7-fluoro-2H-1,4-benzoxazine-3(4H)-ketone compound with a chlorination reagent in a first reaction medium to generate a 2,2-dichloro-7-fluoro-2H-1,4-benzoxazine-3(4H)-ketone compound; (2) performing a chlorine-fluorine exchange reaction of the 2,2-dichloro-7-fluoro-2H-1,4-benzoxazine-3(4H)-ketone compound with a fluorination reagent. The method provided in the invention has a high product yield, adopts safe and easily-available raw materials, generates no intermediate products with potential safety hazards during the reactions, and thus overcomes the defects of high raw material price, poor safety, and generation of intermediate products with potential safety hazards during the reactions in the prior art.

Description

technical field [0001] The invention relates to a preparation method of 2,2,7-trifluoro-2H-1,4-benzoxazin-3(4H)-one compounds. Background technique [0002] WO2012 / 041789 describes that benzoxazinones substituted by 1 or 2 halogens at the 2-position have better herbicidal activity, especially 2,2,7-trifluoro-2H-1,4-benzo The oxazin-3(4H)-one compound [formula (I)] has more excellent herbicidal activity. [0003] [0004] WO2010 / 145992 describes a process for the preparation of 2,2,7-trifluoro-2H-1,4-benzoxazin-3(4H)-one [formula (I-01)], wherein two fluorine The atom is derived from ethyl 2-bromo-2,2-difluoroacetate [formula (V)], and the reaction process is as follows: [0005] [0006] The above-mentioned preparation method has obvious disadvantages: the price of raw materials 2-bromo-2,2-difluoroacetic acid ethyl ester and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) is high , the yield is only 52%, resulting in a very high price of the final product, which lacks mar...

Claims

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Application Information

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IPC IPC(8): C07D265/36C07D413/04
CPCC07D265/36C07D413/04
Inventor 王文军陈建伟
Owner NUTRICHEM LAB CO LTD
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