Synlett 2007(8): 1299-1301  
DOI: 10.1055/s-2007-977415
LETTER
© Georg Thieme Verlag Stuttgart · New York

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

Faith Corbo Gaenzler, Michael B. Smith*
Department of Chemistry, University of Connecticut, 55 North Eagleville Road, Storrs, CT 06269-3060, USA
Fax: +1(860)4862981; e-Mail: michael.smith@uconn.edu;
Further Information

Publication History

Received 19 December 2006
Publication Date:
03 April 2007 (online)

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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.

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Careful examination by HMQC proved that the dichloride was vicinal based on the fact that the singlet at δ = 6.21 ppm coupled to two different carbon atoms.

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Sulfuryl chloride was purchased from Aldrich, and used in many reactions with complete reproducibility. Recently, two batches from Aldrich were used in an identical manner, but required a larger excess of reagent, longer reaction times, and gave poorer yields. Aldrich simply stated that they had a different supplier, but did not elaborate. We could detect no difference in the batches by GC-MS or IR analysis.