Mesityl oxide → 3-Cyclohexene-1-carboxylic acid, 6,6-dimethyl-2-methylene-, ethyl ester

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Reaction Steps

260 g of ethyl acetoacetate were mixed with 200 g of mesityl oxide and 200 g of trifluoroboro-etherate in a vessel cooled externally by water and ice in order to maintain the temperature of the mixture at about 0°-5°. The said mixture is maintained at this temperature for 3 days, poured then onto ice (800 g) and neutralized with about 400 g of Na2CO3. Then it was extracted with ether and, after the usual treatments of separation, washing and drying, the combined organic extracts were concentrated. Distillation of the residue (135 g) gave 115 g of the desired product, b.p. 85°-90°/0.1 Torr, which has a purity of 80% as shown by analysis by means of vapour phase chromatography. The product can subsequently be purified by redistillation.

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