4-Thiobenzonitrile → 4-cyanophenyl 2,3,4-tri-O-acetyl-1,5-dithio-beta-D-xylopyranoside

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Reaction Conditions

Reaction Steps

A suspension of 625 mg (1.76.10-3 mol) of 2,3,4-tri-O-acetyl-5-thio-D-xylopyranosyl bromide, 200 mg (1.48.10-3 mol) of 4-mercaptobenzonitrile and a 400 pm molecular sieve in 10 ml of acetonitrile is stirred in the presence of 605 mg (4.4.10-3 mol) of zinc chloride and 310 mg (1.8.10-3 mol) of silver imidazolate, in the absence of light, under an inert atmosphere. After heating at 50° C. for 3 h, the reaction mixture is filtered on Celite® in ethyl acetate. The filtrate is washed with a 1N solution of hydrochloric acid, water, a 1N solution of sodium hydroxide, water and finally a saturated solution of sodium chloride, dried over magnesium sulfate and evaporated under reduced pressure. After purification by chromatography on silica gel using a hexane/ethyl acetate mixture (3/1 v/v) as the eluent, and precipitation in ether, 100 mg (yield: 17%) of the expected product are obtained.

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