Dithiocarbonic acid derivatives

Nadasy, M. and Harmathy, L. (1970) NEVIKl KozL, (Commun. Res. Inst. Heavy Chem. Inds., Veszprem) 3, 151. 

and Blaak, G. (1960) Contrib. Boyce Thompson Inst., 20, 459. 

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Butylisocyanate, as methyl isothiocyanate (see dithiocarbonic acid derivatives), inhibits the respiration of yeast ceils. Isothiocyanates react with thiol compounds, and their fungitoxicity is reversible. Mailman et al. (1971) found that the toxicity of benomyl to yeast can be decreased by the addition of thiol compounds. 

Buthiobate (S-1358) is a dithiocarbonic acid derivative which is very toxic to powdery mildew fungi (22). The fungicide, butyl 4-r-butylbenzyl-N-(3-pyridyl)-dithiocarbonimidate, has an excellent preventive and curative effect against the powdery mildew fungi of many agricultural and horticultural plants (Kato et al.,... 

Thioacids have a most disagreeable odour and slowly decompose in air. Their boiling points are lower than those of the coiTcsponding oxygen counterparts and they are less soluble in water, but soluble in most organic solvents. An important dithioacid is dithiocarbonic acid (HO—CS2H). Whilst the free acid is unknown, many derivatives have been prepared such as potassium xanthate giving a yellow precipitate of copper xanthate with copper salts ... 

Unlike the inorganic salts of the azido-dithiocarbonic acid, the org derivs are not particularly expl. They puff midly when held in a flame or when heated rapidly on a hot plate. On exposure to light they show no photosensitivity and undergo no coloration... 

Their sensitivities to friction and their brisanee increase with increasing atomic wt. The Amm, K, Rb Cs salts are characterized by their peculiar sensitivity to light. All change color when exposed to sunlight. The Cs salt may even decomp violently during the process of crystn from aq soln. The alkali salts, especially Na, can be used to prepare the heavy metal salts, such as Pb(SCSN3)2, and the alkyl or aryl derivatives of azido-dithiocarbonic acid... 

In the presence of potassium hydroxide, cellulose adds to carbon disulfide (Figure 8.4). In this way potassium xanthate A is produced. It is soluble in water, but restores the water-insoluble cellulose upon addition of acid. The primary protonation product is the dithiocarbonic acid O-cellulose ester B. B reacts just like the unstable carbonic acid derivatives in Figure 8.3, namely via a zwitterion (C) and its decomposition into cellulose (a heteroatom nucleophile)... 

Carbon disulfide is the dithio derivative of C02. It is only a weak electrophile. Actually, it is so unreactive that in many reactions it can be used as a solvent. Consequently, only good nucleophiles can add to the C—S double bond of carbon disulfide. For example, alkali metal alkoxides add to carbon disulfide forming alkali metal xan-thates A (Figure 7.4). If one were to protonate this compound this would provide compound B, which is a derivative of free dithiocarbonic acid. It is unstable in the condensed phase in pure form, just as free carbonic acid and the unsubstituted carbamic acid (Formula B in Figure 7.3) are unstable. Compound B would therefore decompose spontaneously into ROH and CS2. Stable derivatives of alkali metal xanthates A are their esters C. They are referred to as xanthic add esters or xanthates. They are obtained by an alkylation (almost always by a methylation) of the alkali metal xanthates A. You have already learned about synthesis applications of xanthic acid esters in Figures 1.32, 4.13, and 4.14. 

The mixed esters of carbonic acid [see Table I, type (a)] were formerly designated carboalkyloxy, but this term is now avoided, since it was often confused with carboxyalkyl [—(CHj) —CO2H]. A, the mixed esters of dithiocarbonic acid [see Table I (e) R = alkyl] have been termed alkyl xanthogenates or alkyl xanthates, thus relating them to the corresponding acid dithiocarbonates (R = metal), industrially called xanthates, but more precisely termed 0-(/Si-metal thiolthiocarbonyl) derivatives. Of the mixed-ester types and acid types indicated in Table I, examples of (a), (b), (e), (f), and (g) of the former, and (a), (b), and (e) of the latter have so far been reported. For intermolecular esters, examples of (i) and (k), and, for cyclic esters, examples of (0) and (t), have been described. 

In reactions with strong nucleophiles, 3-(methylsulfanyl)-l,4,2-dithiazines behave as derivatives of dithiocarbonic acid and are attacked at position 3. Methylmagnesium iodide and 3-(methylsulf-anyl)-5,6-tetramethylene-l,4,2-dithiazine give the anion of 2-(methylsulfanyl)cyclohexene-l-thiol 4.1... 

The 5-glucopyranosyl phosphorodiamidimidothioate (116) afforded good yields of disaccharides when coupled with several sugar mono-ols in the presence of lutidinium tosylate, the a, S-ratios being about 10 1. Likewise, the A -acetylneuraminic acid derivative (117), made by use of the corresponding dithiocarbonate, acts as a glycosyl donor when and with silver triflate. ... 

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