Mild and safe procedure for hydrolyzing oximes: improved synthesis of 1,2-indandione

Four ketoximes were hydrolyzed to the corresponding ketones in 66-91% yields using 75% sulfuric acid and 37% formaldehyde at room temperature. An earlier procedure involving hydrochloric acid and 37% formaldehyde is extremely hazardous because it leads to the formation of bis(chloromethyl) ether, a potent carcinogen.