1,4-Dihydroxy-2,2,6,6-tetramethylpiperidine → HCID 12068227, compound

Participants

Reaction Steps

A solution of 70% aqueous tert-butyl hydroperoxide (74.8 grams, 609 mmol) is added over 30 minutes to a mixture of 35.0 grams (203 mmol) of 4-hydroxy-1-oxyl-2,2,6,6-tetramethylpiperidine, 2.0 grams of molybdenum trioxide, and 200 ml of ethylbenzene which is preheated to 120° C. The reaction mixture is maintained at reflux temperature throughout the addition, and water is collected in a Dean-Stark trap. The red mixture is heated at reflux for three hours after the addition is complete in order to discharge the red color of the N-oxyl compound. Solids are removed by filtration, and the filtrate is concentrated at reduced pressure to obtain a yellow oil. Purification by flash chromatography (silica gel; 4:1 hexane:ethyl acetate) affords 30.0 grams (53% yield) of the title compound as a white solid melting at 95°-97° C.

Provenance & Evidence