Dithiocarboxylic acids, from disulfide

Under basic conditions, carbanions derived from thiones, thionoesters, or thioamides react with carbon disulfide to give dithiocarboxylic acids, or derivatives that can be cyclized to 1,2-dithioles <76BCJ3128, 80LA483>, For example, the thioindoxyl (130) forms the dithioloindole (131) <82AHC(3i)63>. The 3-aminocarbanions (132) give bis-l,2-dithiol-3-ylidenes (9), probably via 1,2-dithiole-3-thiones (2a) <82ZOR274>. 

Sulfonic acid chloride Thioacyl disulfides from dithiocarboxylic acids... 

An interesting example of a Lewis acid/base reaction between neutral reactants is the formation of tris(n-butyl)phosphonium-dithiocarboxylate, ( -Bu)3P" — 82 , from tris(n-butyl)phosphane and carbon disulfide in solution. As expected, this equilibrium is strongly shifted in favour of the dipolar zwitterion with increasing solvent polarity (diethyl ether dimethyl sulfoxide) [272, 273]. 

Another potentially interesting ligand for transition metals is the recently reported dithiocarboxylate anion RfCSS (32), Treatment of in situ prepared RFLi with excess carbon disulfide results in the formation of a red-brown solution, from which RfCSSH can be isolated after acidification (55% yield). Pure 2,4,6-tris-(trifluoromethyl)dithiobenzoic acid forms a dark red oily liquid. Orange crystalline [CsHioNH2] RfCSS" has been prepared by neutralizing the free acid with piperidine in pentane solution (32), The coordination chemistry of the RfCSS" anion still awaits further investigation. 

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