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Synlett 2004(11): 1901-1904  
DOI: 10.1055/s-2004-830851
LETTER
© Georg Thieme Verlag Stuttgart · New York

Novel N-Dealkylation of N-Alkyl Sulfonamides and N,N-Dialkyl Sulfonamides with Periodic Acid Catalyzed by Chromium(III) Acetate Hydroxide

Liang Xua, Suhong Zhangb, Mark L. Trudell*b
a St Charles Pharmaceuticals, Inc., P.O. Box 850815, New Orleans, Louisiana 70185, USA
b Department of Chemistry, University of New Orleans, New Orleans, Louisiana 70148, USA
Fax: +1(504)2806860; e-Mail: mtrudell@uno.edu.;
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Publication History

Received 19 March 2004
Publication Date:
28 July 2004 (online)

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Abstract

Chromium(III) acetate hydroxide has been found to be an efficient catalyst for N-dealkylation of N-alkyl sulfonamides and N,N-dialkyl sulfonamides to furnish sulfonamides in good to excellent yields with periodic acid in acetonitrile at room temperature.

Key words

N-dealkylation - N-alkyl sulfonamide - N,N-dialkyl ­sulfonamide - periodic acid - chromium(III) acetate hydroxide

18

Typical Procedure for Dealkylation of N -Alkyl-sulfonamides and N , N -Dialkylsulfonamides with Periodic Acid-Chromium(III) Acetate Hydroxide: A mixture of H5IO6 (4.6 g, 20 mmol), chromium(III) acetate hydroxide [11 mg, 2.5 mol% of Cr(III)] and N,N-dialkyl sulfonamide (2 mmol) in MeCN (50 mL) was stirred at r.t. until the reaction was complete (monitored by TLC). The intermediate monodealkylation products of the dialkylsulfonamides can be observed by TLC during the reaction. The reaction mixture was then filtered and the filtrate was concentrated by rotary evaporation. The residue was extracted with EtOAc (120 mL), washed, respectively, with sat. NaHCO3 solution, sat. Na2S2O3 solution, brine and dried over MgSO4. The solvent was removed by rotary evaporation and the resultant residue was purified by flash chromatography eluting with EtOAc-hexanes (1:8) to afford the pure unsubstituted sulfonamides (1H NMR, mp).