Synthesis method of 7-fluorine-6-amino-4-(2-propargyl)-1,4-benzoxazine-3(4H)-ketone derivative

Abstract

The invention relates to the field of organic synthesis, in particular to a synthesis method of a 7-fluorine-6-amino-4-(2-propargyl)-1,4-benzoxazine-3(4H)-ketone derivative. The method includes the step of conducting reaction under the catalysis effect of organic acid and salt with 6-amino-7-fluorine-4-propinyl-1,4-benzoxazine-3(4H)-ketone and 3,4,5,6-tetrahydrophthalic anhydride as the raw materials to obtain the 7-fluorine-6-amino-4-(2-propargyl)-1,4-benzoxazine-3(4H)-ketone derivative, wherein acetic acid and potassium acetate are optimally selected as catalysts, and potassium acetate is low in price. Compared with an existing catalytic reaction method with piperidine as the catalyst, the method has the outstanding advantage of being low in production cost with acetic acid and potassium acetate as the catalysts; the reaction yield can reach 91% or above, the purity can reach 99.5% or above, and the product purity and impurity specification meet related standards.

Description

technical field [0001] The present invention relates to the technical field of organic synthesis, in particular to a method for synthesizing 7-fluoro-6-amino-4-(2-propargyl)-1,4-benzoxazin-3(4H)-one derivatives . Background technique [0002] 7-Fluoro-6-amino-4-(2-propargyl)-1,4-benzoxazin-3(4H)-one derivatives, also known as propargylfluramid (quick harvest), is a A class of IV-phenylphthalimide herbicides absorbed by young shoots and leaves, which can effectively control annual broad-leaved weeds and gramineous weeds. At the same time, because of the characteristics of high efficiency, low toxicity, high selectivity and low environmental pollution, the herbicide has a very broad market prospect. [0003] At present, there are several main methods for the synthesis of fluflumecil propargyl: [0004] US4640707 discloses a method for the preparation of diflufenamide propargyl, the method comprises using acetic acid as a solvent, without catalyst, 6-amino-7-fluoro-4-propyny...

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Problems solved by technology

[0004] US4640707 discloses a method for the preparation of fluorenzine propargyl, the method comprising acetic acid as a solvent, without catalyst, 6-amino-7-fluoro-4-propynyl-1,4-benzoxazine-3 (4H)-ketone is reacted with 3,4,5,6-tetrahydrophthalic anhydride to obtain the product diflufenamide. According to this patent, the purity of the product is not high and cannot meet the requirements of the existing market for product purity. More than 99.2%; CN105061416A discloses a method for preparing fluflumecil propargyl, which comprises using toluene, ethylene dichloride or methyl isobutyl ketone as solvent, adding basic nitrogen-containing organic matter or organic acid and nitrogen-containing The mixture of organic matter is a catalyst, prepared by the dehydration reaction of 6-amino-7-fluoro-4-propynyl-1,4-benzoxazin-3(4H)-one and 3,4,5,6-tetrahydrophthalic anhydride Product flufenazol

The catalysts reported in this patent, especially the preferred piperidine, are regulated chemicals, inconvenient to use and expensive

[0005] In summary: the existing methods have the following deficiencies: 1. The product has low purity and does not meet the specifications

2. The catalyst used, especially piperidine, is a precursor to poisonous raw materials, and its industrial application is limited and expensive

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