Sulfuric Acid → 1-Methyl-6-oxabicyclo[3.2.1]octan-7-one

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A solution of 1-methyl-3-cyclohexenecarboxylic acid (47 g) in chloroform (200 ml) was cooled to -5° C. Then, a mixture of conc. H2SO4 (100 ml) and chloroform (100 ml) was added. After stirring at 0° C. for 15 minutes, the mixture was poured onto ice (500 g) and extracted with chloroform. The chloroform layer was washed in sequence with water, saturated aqueous sodium hydrogen carbonate solution and water, and dried (MgSO4), and the chloroform was distilled off. The residual oily substance was subjected to column chromatography using silica gel (500 g) and eluted with ether-hexane (1:3 v/v). From the first eluate fractions, crystals of 1-methylcyclohexane-1,3-carbolactone (28.0 g, 59.6% yield) were recovered and recrystallized from hexane. m.p. 37°-38° C.

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