4,5-Dichloro-1,2-dithiole-3-thione in the synthesis of benzimidazole, benzoxazole and benzothiazole derivatives of 1,3-dithioles

Synthesis and Reactivity of 3H-1,2-dithiole-3-thiones

“…As a rule, the reaction of non-fused dithiolethiones is stopped at the stage of addition of one mole of an alkyne (Scheme 34). Usually, one equivalent of an alkyne should be added to the reaction mixture to obtain 1,3-dithioles 34, and the conversion is carried out at room temperature or even below it [37,76,77], but in some cases refluxing with an excess of an alkyne in xylene or benzene was employed [64,66,78,79]. The yields of 1,3-dithioles can vary widely from 20% to the quantitative yield.…”

Recent advances in the synthesis of 2-substituted benzothiazoles: a review

“…Ogurtsov et al have noted that a 1,3dipolar cycloaddition of 4,5-dichloro-1,2-dithiole-3-thione in dimethyl acetylenedicarboxilate (DMAD) gave stable aliphatic thioacyl chloride, which is highly reactive towards nucleophiles such as ortho-substituted amines to afford benzothiazole derivatives of 1,3-dithioles in good yield (Scheme 48, Method 1). 142 This new protocol for the synthesis of 2-substituted benzothiazole can be performed in one-pot at room temperature using 4,5-dichloro-1,2-dithiole-3-thione in a 3 : 1 mixture of xylene and tetrahydrofuran (THF) by adding DMAD and then heating with the corresponding ortho-substituted aniline without the isolation of thioacylchloride.…”

Synthesis of Thienothiopyranthiones by a New Molecular Rearrangement

“…Thioacyl chloride 3 and all the other thioacyl chlorides prepared (see below) are stable, deep red solids. Their stability was attributed to a significant interaction between the thiocarbonyl and a heterocyclic sulfur atom, which could reduce the electrophilicity of the thiocarbonyl group . This is now supported by an X-ray crystal structure determination of 3a , which shows the planarity of the quasibicyclic portion of the molecule, with a partial S···S bond length of 2.91 Å about midway between a normal S−S bond (2.05 Å) and the sum of its van der Waals radii (3.68 Å) (Figure )…”

“…We have recently shown 6 that 4,5-dichloro-1,2-dithiole-3-thione 2 , readily prepared from 3,4,5-trichloro-1,2- dithiolium chloride, undergoes the same initial 1,3-cycloaddition to DMAD to give the adduct 3 almost quantitatively at room temperature. For an aliphatic thioacyl chloride, 3 is unusually stable but still highly reactive toward nucleophiles such as ortho-substituted anilines to give benzimidazole, benzoxazole, and benzothiazole derivatives of 1,3-dithioles . Thioacyl chloride 3 and all the other thioacyl chlorides prepared (see below) are stable, deep red solids.…”