A Dichlorination-Reductive-Dechlorination Route to N-Acetyl-2-Oxazolone

Abstract We have shown that sulfuryl chloride is an efficient ­reagent for the conversion of 2-oxazolidinone into the dichloro ­derivative, N-acetyl-4,5-dichloro-2-oxazolidinone. Subsequent Zn/AcOH reductive dehalogenation of this TRANS-dichloride gives N-acetyl-2-oxazolone. The dichloride was previously reported as an undesired side product in the preparation of N-acetyl-2-oxazolone from the monochloro oxazolidinone. In our hands, the dichloride is a key intermediate in a new synthesis of 2-oxazolone, that avoids the use of chlorine gas.