Acetic Anhydride → 1-Acetoxy-2-(6-carbethoxyhexyl)cyclopent-1-ene

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Reaction Steps

A stirred solution of 100 g. of 2-(6-carbethoxyhexyl)cyclopentan-1-one (Example 9) in 250 ml. of acetic anhydride containing 0.940 g. of p-toluenesulfonic acid monohydrate is heated to boiling under partial reflux allowing distillate at 118° C. or less (i.e., acetic acid) to escape through a Vigreaux column equipped with a condenser to collect the distillate. After 16 hours, during which period acetic anhydride is added in portions in order to keep the solvent level at at least 100 ml., the solution is cooled and poured cautiously into a stirred cold mixture of saturated sodium bicarbonate solution (400 ml.) and nexane (250 ml.). The resulting mixture is stirred for an additional 30 minutes during which period solid sodium bicarbonate is added periodically to insure a basic solution. The hexane layer is separated and washed with saturated sodium chloride solution, dried with anhydrous magnesium sulfate and taken to dryness. Distillation of the residual oil gives 102 g. (87%) of pale yellow oil, b.p. 118° C. (0.07 mm.).

Provenance & Evidence