Synlett 2002(2): 0346-0348
DOI: 10.1055/s-2002-19764
LETTER
© Georg Thieme Verlag Stuttgart · New York

Hexamethyldisilazane (HMDS) Promotes Highly Efficient Oxidative Coupling of Thiols by DMSO Under Nearly Neutral Reaction Conditions

Babak Karimi*, Daryoush Zareyee
Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), P. O. Box 45195-159, Gava Zang, Zanjan, Iran
Fax: +98(241)4249023; e-Mail: karimi@iasbs.ac.ir;
Further Information

Publication History

Received 24 October 2001
Publication Date:
02 February 2007 (online)

Abstract

A variety of thiols were efficiently converted to their disulfides using DMSO in the presence of hexamethyldisilazane (HMDS) under almost neutral reaction conditions. Due to the neutrality of the reaction medium in this protocol, acid sensitive functional groups survived intact.

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General Procedure for Oxidative Coupling of Thiols to Disulfides: To a solution of thiol (3 mmol) and DMSO (9 mmol) in anhyd acetonitrile (5 mL), HMDS (3.6 mmol) was added and the resulting solution was magnetically stirred at r.t. The progress of the reaction was monitored by TLC. After completion of the reaction, the mixture was poured into 10% aq NaOH solution. The organic layer was separated and the aq phase was extracted with ether (3 × 50 mL). The organic extracts were combined together and was washed successively with 10% NaOH (25 mL) and water (2 × 50 mL) and dried over anhyd Na2SO4. Evaporation of the solvent under reduced pressure gave the almost pure disulfide. Further purification of the product was achieved by re-crystallization or column chromatography through a short silica-gel column.