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The 8 coumarin derivatives have been synthesized from 8 starting materials(2-hydroxy-benzophenone, 2,2'-dihydroxybenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-5-methylbenzophenone, 5-chloro-2-hydroxy-4-methylbenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-ethoxybenzophenone, 2-hydroxy-4,4'-dimethoxybenzophenone) with phenylacetic acid and Ac2O/TEA in acetone at reflux temperature. The ratio of o-hydroxybenzophenone, phenylacetic acid, Ac2O and TEA is 1 : 1: 8: 8 in acetone. Our results showed higher products yields of coumarin derivatives than Shama and Ray's method in previous papers. A new intermediate form was proposed to our mechanism of coumarin synthetic method.
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