Preparation method of 2-coumaranone

Abstract

The invention discloses a preparation method of 2-coumaranone. The method is divided into two steps: (1) preparation of 2-hydroxyphenylacetic acid: adding 2-cyclohexen-1-one, glyoxylic acid and a solvent into a reactor to carry out a reaction under an acidic or alkaline condition, recovering the solvent after the reaction is finished, performing recrystallization to obtain the pure product of 2-hydroxyphenylacetic acid; and (2) preparation of 2-coumaranone: adding 2-hydroxyphenylacetic acid prepared by step (1) in a reactor with a water separator, adding a solid catalyst and a solvent, carrying out a reaction under heating reflux until no water is separated, performing cooling to room temperature, performing filtering to remove the solid catalyst, recovering the solvent by decompression, and performing recrystallization to obtain 2-coumaranone. According to the method, the raw materials are cheap and easy to obtain, the main raw material of 2-cyclohexen-1-one is prepared by the chlorination of cyclohexanone in a non-aqueous system with chlorine gas and then performing elimination, and glyoxylic acid has 50% commercialized aqueous solution. The synthesis route is short, the operation is simple, the yield is high, the cost is low, and the three wastes are greatly reduced.

Description

technical field [0001] The invention belongs to the technical field of chemical synthesis, in particular to a preparation method of benzofuran-2-(3H)-one. Background technique [0002] Benzofuran-2-(3H)-one is an important raw material for the pesticide azoxystrobin and also a raw material for pharmaceutical synthesis. Looking at the patents for the synthesis or preparation of the compound in various countries in the world, the preparation methods are mainly: [0003] 1. Hydrolysis of o-chlorophenylacetonitrile to obtain o-chlorophenylacetic acid, alkaline hydrolysis and subsequent acidification of o-chlorophenylacetic acid under the catalysis of a copper catalyst to obtain o-hydroxyphenylacetic acid, and intramolecular esterification of o-hydroxyphenylacetic acid to obtain benzofuran-2-( 3H)-ketone, with reference to U.S. Patent US5221772 (1993), its synthetic route is: [0004] [0005] The advantage of this method is that the raw material o-chlorophenylacetonitrile i...

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Problems solved by technology

The biggest disadvantage of this method is that there are many three wastes, especially o-chlorophenylacetic acid is obtained by copper-catalyzed alkaline hydrolysis to obtain the corresponding double sodium salt and then acidified, which produces nearly 10 times the amount of high-salt wastewater per ton of product, which greatly pollutes the environment.

[0008] The advantage of this synthesis method is that the synthesis route is short, but the condensation intermediate uses noble metal as a catalyst to dehydrogenate under high temperature and pressure, which has high cost, difficult operation and low yield

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