3,4-Dichloro-1,2,5-thiadiazole: a commercially available electrophilic sulfur transfer agent and safe resource of ethanedinitrile

Abstract

3,4-Dichloro-1,2,5-thiadiazole is introduced as a safe and efficient sulfur transfer reagent. By applying this commercially available reagent, the symmetrical trisulfides and ethanedinitrile were simultaneously obtained by reacting various thiols with this reagent at room temperature. This reagent is non-toxic, inexpensive, and commercially available. In addition, no higher-order polysulfides were detected in all cases after the completion of the reaction. The short reaction times (20–50 min), excellent selectivity, and high yield of the trisulfides are some attractive merits of this reagent for the preparation of trisulfides. The reaction is one-pot, and isolation-purification of intermediates is not required. The procedure was readily scaled up to 5 grams. A mechanism is presented to explain the chemistry.