Lactones (cyclic esters) HO OH + H2O 6-hydroxyvale ric acid δ-vale rolactone OH H2C OH Y-hydroxye nanthic acid Y-e nantholactone Lactones (cyclic esters) OH O HO -hydroxyvaleric acid O O -valerolactone + H2 O OH O OH -hydroxyenanthic acid O O -enantholactone + H2 O