- A method for preparing [...] (by machine translation)
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The present invention discloses a afloqualone preparation method, which comprises: adopting an isatin anhydride as a starting raw material, carrying out nitration, reduction and acetylation to synthesize a key intermediate N-(2-amino-5-acetylaminobenzoyl)o-toluidine, and then carrying out aminolysis, cyclization, fluorine exchange and deprotection to obtain the target product afloqualone. The afloqualone preparation method has characteristics of cheap and easily-available raw materials, production cost reduction, elimination of use of highly-toxic and highly-harmful reagent fluoroacetyl chloride in the existing literature method, safety and environmental protection. In addition, tetrabutyl ammonium bromide is adopted as the phase transfer catalyst of the fluorine exchange reaction so as to substantially improve the conversion rate of the fluorine exchange reaction, and the total yield of the target product afloqualone prepared from the starting raw material isatin anhydride can be more than 60.0%.
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Paragraph 0057-0059
(2017/02/28)
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