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发展了一条1,2,6,7-四氢-8H-茚并[5,4-b]呋喃-8-酮的新合成方法,以价廉、易得的对溴苯酚为原料,在无水碳酸钾作用下与2-溴乙醛缩二乙醇缩合后用多聚磷酸(PPA)环合得5-溴苯并呋喃,该中间体与丙烯酸甲酯在Pd(OAc)2催化下,经Heck偶合反应得3-(苯并呋喃-5-基)丙酸甲酯,在氢氧化钠水溶液中经Raney Ni催化氢化和水解一锅反应得3-(2,3-二氢苯并呋喃-5-基)丙酸,再经二溴代、Friedel-Crafts酰化反应和氢解脱溴,得1,2,6,7-四氢-8H-茚并[5,4-b]呋喃-8-酮,7步反应总收率49.9%.该方法原料易得、反应条件温和、操作简便、产物分离纯化容易,收率良好,适合大规模制备1,2,6,7-四氢-8H-茚并[5,4-b]呋喃-8-酮.
A new synthesis method of 1,2,6,7-tetrahydro-8H-indeno [5,4-b] furan-8-one was developed. The starting materials of p-bromophenol, Under the action of potassium carbonate and potassium carbonate, the 2-bromoacetaldehyde diethyl acetal was condensed and polymerized with polyphosphoric acid (PPA) to obtain 5-bromobenzofuran. This intermediate was reacted with methyl acrylate under the catalysis of Pd (OAc) 2, Heck coupling reaction of methyl 3- (benzofuran-5-yl) propionate, sodium hydroxide aqueous solution was Raney Ni catalytic hydrogenation and hydrolysis one-pot reaction 3- (2,3-dihydrobenzofuran- 5-yl) propionic acid, followed by dibromination, Friedel-Crafts acylation and hydrogenolysis to give 1,2,6,7-tetrahydro-8H- indeno [5,4-b] furan- -one, the total yield of 7-step reaction is 49.9% .The raw material is easy to obtain, the reaction conditions are mild, the operation is simple, the product is easy to separate and purify, the yield is good, and the method is suitable for large scale preparation of 1,2,6,7-tetrahydro-8H -indeno [5,4-b] furan-8-one.