Lactone prepn - by treating cyclic ketone with urea - hydrogen peroxide adduct in presence of formic acid

摘要

Lactones are prepd. by treating a cyclic ketone with a urea-H2O2, adduct at 0-100 degrees C., pref. 20-60 degrees C., in the presence of formic acid. Cyclopentanone is converted into DELTA-valerolactone and cyclohexanone into eksilon-caprolactone, in high yields using an adduct prepd. from dilute H2O2. By-pdt. formation is low, and use of potentially explosive per acids and concentrated H2O2, is avoided. The cyclic keton is treated with the adduct in the presence of a mixt. of 85% formic acid and ethyl acetate pref. at a volume ratio of 80 : 20.