Potassium Hydroxide → Ethyl alpha-(3,3-dichloroallyl)isovalerate

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Reaction Steps

In 20 g of ethanol were dissolved 8.8 g of the above diethyl isopropyl-(3,3-dichloroallyl)malonate and a solution of 6.4 g of potassium hydroxide in 10 g of water was added to the above ethanol solution. The mixture was refluxed overnight. Then, the reaction mixture was distilled to remove the ethanol and a sufficient amount of dilute hydrochloric acid was added to make the residue acidic. The residue was extracted with diethyl ether and the ethereal layer was dried over anhydrous magnesium sulfate and distilled to remove the low-boiling fraction. By this procedure there was obtained a mixture of isopropyl-(3,3-dichloroallyl)malonic acid and morbethyl isopropyl-(3,3-dichloroallyl)malonate. This mixture was subjected to decarboxylation reaction at 180° to 230° C. under a reduced pressure of 35 to 60 mmHg, whereupon 6.0 g of a mixture of α-(3,3-dichloroallyl) isovaleric acid and ethyl α-(3,3-dichloroallyl)isovalerate was obtained. In 20 g of ethanol were dissolved 6.0 g of the above decarboxylated mixture and a solution of 1.2 g of sodium hydroxide in 10 g of water was added to the above solution. The mixture was refluxed for 4 hours, after which the ethanol was distilled off. The residue was made acidic with dilute hydrochloric acid and extracted with diethyl ether. The ethereal layer was dried over anhydrous magnesium sulfate and distilled to remove the low-boiling fraction. By the above procedure there were obtained 4.2 g of α-(3,3-dichloroallyl)isovaleric acid, the NMR spectrum of which appears below [yield: 70% based on diethyl isopropyl-(3,3-dichloroallyl)malonate].

Provenance & Evidence