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Preparation method of 6-amino-7-fluoro-1,4-benzoxazine-3(4H)-ketone

A benzoxazine and amino technology, applied in the field of 6-amino-7-fluoro-1, can solve the problems of complex process, poor safety, low reaction conversion rate and product yield

Active Publication Date: 2011-04-06
NUTRICHEM LAB CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] In summary, prior art is preparing 6-amino-7-fluoro-1,4-benzo There are three deficiencies in the method of oxazin-3(4H)-one: 1. The process is more complicated and industrialization is more difficult; 2. The raw materials are more expensive or poor in safety; 3. The reaction conversion rate and product yield are relatively low

Method used

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  • Preparation method of 6-amino-7-fluoro-1,4-benzoxazine-3(4H)-ketone
  • Preparation method of 6-amino-7-fluoro-1,4-benzoxazine-3(4H)-ketone
  • Preparation method of 6-amino-7-fluoro-1,4-benzoxazine-3(4H)-ketone

Examples

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Embodiment 1

[0026] 6-Amino-7-fluoro-1,4-benzo Preparation of azin-3(4H)-one:

[0027] Hydrogenation: Add 2-(5-fluoro-2,4-dinitrophenoxy)acetic acid (60 g, 0.23 mol) to a 2 L autoclave, the solvent system is a mixture of methanol (300 mL) and water (300 mL), The hydrogenation catalyst was 5% Pd / C (8 g). Close the autoclave, use vacuum and nitrogen (10kg / cm 2 ) to replace the air 3-5 times. Keep the hydrogen pressure at 20kg / cm 2 The hydrogenation reaction was carried out at room temperature. In this embodiment, the substrate of the hydrogenation reaction was 2-(5-fluoro-2,4-dinitrophenoxy)acetic acid. The hydrogenation reaction was carried out for 8 hours. When the hydrogen pressure remained constant for 30 minutes, the reaction was considered complete.

[0028] Cyclization reaction: The mixture obtained in the hydrogenation reaction was filtered under nitrogen atmosphere to remove Pd / C. Add hydrochloric acid to the filtrate to adjust the pH to 1, carry out the cyclization reaction ...

Embodiment 2

[0030] 6-Amino-7-fluoro-1,4-benzo Preparation of azin-3(4H)-one:

[0031] Hydrogenation: Add 2-(5-fluoro-2,4-dinitrophenoxy)acetic acid (60 g, 0.23 mol) to a 2 L autoclave, the solvent system is a mixture of methanol (300 mL) and water (300 mL), The hydrogenation catalyst was 5% Pd / C (8 g). Close the autoclave, use vacuum and nitrogen (10kg / cm 2 ) to replace the air 3-5 times. Keep hydrogen pressure at 30kg / cm 2 , the hydrogenation reaction was carried out at 10°C. In this example, the substrate of the hydrogenation reaction was 2-(5-fluoro-2,4-dinitrophenoxy)acetic acid. The hydrogenation reaction was carried out for 8 hours, and when the hydrogen pressure remained constant for 30 minutes, the reaction was considered complete.

[0032] Cyclization reaction: The mixture obtained in the hydrogenation reaction was filtered under nitrogen atmosphere to remove Pd / C. Add hydrochloric acid to the filtrate to adjust the pH to 1, carry out the cyclization reaction under acidic ...

Embodiment 3

[0034] 6-Amino-7-fluoro-1,4-benzo Preparation of azin-3(4H)-one:

[0035] Hydrogenation: Add 2-(5-fluoro-2,4-dinitrophenoxy)acetic acid (60 g, 0.23 mol) to a 2 L autoclave, the solvent system is a mixture of methanol (300 mL) and water (300 mL), The hydrogenation catalyst was 5% Pd / C (12 g). Close the autoclave, use vacuum and nitrogen (10kg / cm 2 ) to replace the air 3-5 times. Keep the hydrogen pressure at 20kg / cm 2 , carry out the hydrogenation reaction at 20° C. In this embodiment, the substrate of the hydrogenation reaction is 2-(5-fluoro-2,4-dinitrophenoxy)acetic acid. The hydrogenation reaction was carried out for 8 hours, and when the hydrogen pressure remained constant for 30 minutes, the reaction was considered complete.

[0036] Cyclization reaction: The mixture obtained in the hydrogenation reaction was filtered under nitrogen atmosphere to remove Pd / C. Add hydrochloric acid to the filtrate to adjust the pH to 1, carry out the cyclization reaction under acidic ...

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Abstract

The invention provides a preparation method of 6-amino-7-fluoro-1,4-benzoxazine-3(4H)-ketone, which comprises the following steps: taking 2-(5-fluoro-2,4-dinitrobenzene oxygen) acetic acid as an initial raw material; carrying out hydrogenation reaction to generate 2-(5-fluoro-2,4-diaminobenzene oxygen) acetic acid; and then, carrying out cyclization reaction to obtain the 6-amino-7-fluoro-1,4-benzoxazine-3(4H)-ketone.

Description

technical field [0001] The present invention relates to 6-amino-7-fluoro-1,4-benzo Process for the preparation of oxazin-3(4H)-ones. Background technique [0002] 6-Amino-7-fluoro-1,4-benzo Azin-3(4H)-one is an important pesticide intermediate, which is used in the preparation of the herbicide flufenazin (quick harvest). There are multiple synthetic methods for the synthesis of fluorentrafen, such as Lyga, John W. etc. in Pesticide Science, 1999, 55 (3), 281-287, the synthesis of fluorfen is reviewed; 6-amino-7-fluoro-4-propynyl-1,4-benzo It can be obtained by reacting oxin-3(4H)-one with 3,4,5,6-tetrahydrophthalic anhydride. 6-amino-7-fluoro-1,4-benzo Azin-3(4H)-one and propyne bromide under the action of sodium hydrogen give 6-amino-7-fluoro-4-propynyl-1,4-benzo Azin-3(4H)-one. [0003] U.S. Patent No. 4,803,270 describes the hydrogenation reaction of 2-(5-fluoro-2,4-dinitrophenoxy)acetic acid and its esters under the catalysis of palladium / carbon or platinum / c...

Claims

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Application Information

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IPC IPC(8): C07D265/36
Inventor 吴浩王良清罗世英黄民富绵丽娟田爱俊
Owner NUTRICHEM LAB CO LTD
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