Bi alkyl xanthates and thiuram disulfides

Bi(alkyl xanthates) [dithiodi(thioformates)], (RO—CS—S—)2, and thiuram disulfides [dithiodi(formamides)], (NH2—CS—S—)2, are formed by oxidation of xanthates and salts of dithiocarbamic acid, respectively. Thioureas can be dehydrogenated analogously to di(amidino) disulfide salts, [+NH2=C(NH2)—S—)2 2X , by a wide variety of oxidizing agents. Reaction with bromine in chloroform is particularly satisfactory for these reactions.799 

Dithiodi(thioformates [bi(ethyl xanthates) [) 800 The potassium alkyl xanthate is dissolved in water and cooled in ice while a rapid stream of air containing 5-10 % of chlorine is led through until treating a sample of the liquid with copper sulfate no longer gives a precipitate of copper xanthate. The precipitate or oil produced is separated, taken up in ether, dried, recovered, and distilled. 

Iron(m) chloride,801 iodide,802 and potassium hexacyanoferrate(m)803 are among other oxidants proposed for use with dithiocarbamates. 

Dithiocarbamic salts are suitable starting materials for the preparation of isothiocyanic esters (mustard oils), their reactions with heavy-metal salts,771 chloroformic esters,772 phosgene,768 carbodiimides,805 phosphorus oxychloride,806 aryl cyanates,732 or sodium hypochlorite807 usually giving good yields. Reaction of amines 808,809 or their hydrochlorides with thiophosgene810 is also generally applicable. 

Preparation of isothiocyanic esters from dithiocarbamic salts  

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