| A new way of synthesis 2-methoxy-4'-trifluoromethyl acetophenone by the method of crossed ester condensation was investigated in the overall yield of higher than 85%. The new method overcomes disadvantages existing in the present methods. It is successful both in theory and in practice, and it enables the industrial production of the title compound.The main research of this study contains: 1. Crossed ester condensation reaction: Starting from methyl 4-trifluoromethyl benzoate and methyl methoxyacetate, β-carbonyl carboxylic ester was synthesized in basic condition via crossed ester condensation reaction. The optimum conditions are as follows: the mole ratio is methyl 4-thrifluoromethyl benzoate : methyl methoxyace-tate = 1 : 1.5, the reaction time is 12h, the reaction temperature is at 26~30 ?C, and the suitable solvent is DMSO. The yield of this step reaches 88.8%. 2. Hydrolysis and decarboxylation reaction: In acid condition, the β-carbonyl carboxylic ester was hydrolyzed to give β-carbonyl carboxylic acid, and the β-carbonyl carboxylic acid was decarboxylated to give 2-methoxy-4'-trifluoromethyl acetophenone. The optimum conditions of this step are as follows: the mass ratio is β-carbonyl carboxylic ester : sulfuric acid solution : water : methanol = 1 : 0.53 : 2.47 : 11.44, the suitable concentration of sulfuric acid solution is 1.8~2.0mol·L-1, and the reaction time is 15h. In this step the yield is up to 97.8%. The product was corroborated by 1HNMR and IR.
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