Methanol → Methyl 2,2-dimethyl-3-(2,2,2-trichloroethyl)cyclopropane-1-carboxylate

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Reaction Steps

To 250 ml of methanol solution containing 36 g of sodium hydroxide were added 26.8 g of 2,2-dimethyl-3-(2',2',2'-trichloroethyl)-cyclopropyl methyl ketone (purity: 97.9%, cis/trans ratio: 91.5/8.5) under cooling with ice, and then 27.6 g of chlorine gas were absorbed from the surface of the solution for 100 minutes and stirred for 30 minutes. Then 25.2 g of sodium sulfite (7 hydrate) and 200 ml of water were added and the mixture was stirred for 30 minutes to decompose excess hypochlorite. Then the reaction mixture was made acidic with conc. hydrochloric acid. After separating lower organic layer deposited, water layer was subjected to extraction with ether, and the ether layer was mixed with the separated organic layer and washed with sodium bicarbonate aqueous solution and a saturated sodium chloride aqueous solution. After distilling off the ether, vacuum distillation was carried out to obtain 8.3 g of methyl 2,2-dimethyl-3-(2',2',2'-trichloroethyl)-cyclopropanecarboxylate, b.p. 77°-86° C./0.4 mmHg, cis/trans ratio 88/12, purity 87.8%, yield 26.3% and 15 g of 2,2-dimethyl-3-(2',2',2'-trichloroethyl)-cyclopropanecarboxylic acid, b.p. 104°-120° C./0.4 mmHg, cis/trans ratio 82.8/17.2, purity 91.8%, yield 52.0%. Further, the sodium bicarbonate aqueous wash solution was acidified to obtain 1.4 g of 2,2-dimethyl-3-(2',2',2'-trichloroethyl)-cyclopropanecarboxylic acid.

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