Water → 5-Cyclododecylidenepentanoic acid

関与物質

反応手順

Dry dimethylsulfoxide (50 ml, distilled from calcium hydride) and 24.1 ml (0.06 mole) of the sodium salt of dimethylsulfoxide (2.49 M in dimethylsulfoxide, Fieser and Fieser, "Reagents for Organic Synthesis", 1:310 [1967]) were mixed together and cooled in an ice-water bath. Then 13.29 g (0.03 mole) of (4-carboxybutyl) triphenylphosphonium bromide (Aldrich Chemical Co.) was added thereto and the mixture was stirred for 30 min. Cyclododecanone (3.64 g, 0.02 mole; Aldrich Chemical Co.: Beilstein 7[2],36) was dissolved in 10 ml of dry dimethylsulfoxide and added to the above mixture and the mixture was stirred for 15 hr at room temperature. The resulting mixture was then poured into 500 ml of water. This aqueous mixture was extracted with 900 ml (3×300 ml) of ether-ethyl acetate (1:1 V/V). The aqueous phase was acidified (pH 1 to 2) with 30 ml of concentrated hydrochloric acid. The aqueous phase was then extracted with 900 ml (3×300 ml) of ether-hexane (1:1 V/V). The ether-hexane extract was then dried over anhydrous magnesium sulfate, filtered, and the solvent removed in vacuo. The resultant product was recrystallized from ethanol-water to yield 2.0 g (36.2%) of 5-cyclododecylidenepentanoic acid (mp 70°-72° C.) having the following physical characteristics:

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