Thiolates, reactions, carbon disulfide

Robert and co-workers (239,240) discovered novel conversions of 2-amino-1,3-dithiolium-4-olates (348) into other mesoionic heterocycles. For example, reaction of 348 with carbon disulfide, phenyl isocyanate, or phenyl isothiocyanate affords l,3-dithiolium-4-thiolates (349), l,3-thiazolium-4-olates (350), and 1,3-thiazolium-4-thiolates (351), respectively. Some of these reactions proceed via the ring-opened ketene tautomer of 348 (240). 

Benzobis(trithiolo)pentathiepin 106 was isolated as a by-product from reaction of the thiolates with sulfur dichloride by extraction with carbon disulfide and removal of the solvent (Equation 19) <1995T2533>. 

The formation of complexes of l,2,3,4-thiatriazole-5-thiol has been well described in CHEC-II(1996) 1,2,3,4-thiatriazole-5-thiol can form complexes with various metals such as palladium, nickel, platinum, cobalt, zinc, etc. <1996CHEC-II(4)691>. These complexes can be prepared either by cycloaddition reactions of carbon disulfide with metal complexes of azide anion (Equation 20) or directly from the sodium salt of l,2,3,4-thiatriazole-5-thiol with metal salts. For instance, the palladium-thiatriazole complex 179 can be obtained as shown in Equation (20) or it may be formed from palladium(ll) nitrate, triphenylphosphine, and sodium thiatriazolate-5-thiolate. It should be noted that complexes of azide ion react with carbon disulfide much faster than sodium azide itself. 

The reaction of carbon disulfide with a-functional phosphonates [(Rl0)2P(0)CH2X] in the presence of bases gives di-thiolates which, on treatment with gem-dihalides (R2CHBr2), yield (46) (94MI409). 1,3-Dithietanes (47) on reaction with hydrazides (RCONHNH2) yield the 1,3,4-oxadiazoles (48) (94H185,... 

The reactivity of select uranium(IV) thiolate compounds has been inyestigated. The product (SPr )2C=S was identified from reaction of carbon disulfide with U(SPr )4. ... 

Carbon disulfide is a valuable synthon (see Chapter 9, p. 147) which can be used for the synthesis of thiocarbonic acid derivatives. Thus, carbon disulfide reacts with ammonium polysulfide or hydrogen sulfide to give trithiocarbonic acid (70) or symmetrical esters (73) after reaction with an alkyl halide. With alkoxides or thiolates, carbon disulfide forms xanthates (77) or S-alkyl trithiocarbonates the latter by further treatment with alkyl, acyl or diazonium halides affords the derivatives (74)-(76) (Scheme 39). 

Substituents such as chloro, bromo, sulfanyl, or phenoxy in position 2 of phenylsulfonamides are sufficiently reactive to allow ring closure reactions by treatment with carbon disulfide/alkali hydroxide in ethanol43-45 or dimethyl sulfoxide.46 The resulting alkali thiolates 4 may then be methylated43 44 by dimethyl sulfate to give the 3-(methylsulfanyl)-1,4,2-benzodithiazine 1,1-dioxides. 

Cu(II) to yield a paramagnetic Cu(II)-thiolate complex/ Carbon dioxide coordinated to Ni(0) may be reduced to CO by R—SH (R = H, alkyl, benzyl, phenyll, or substituted phenyl) providing a model for carbon monoxide dehydrogenase enzyme. The disulfide generated in this reaction reacts further with the Ni(0) complex to give Ni(SR)2/ The kinetics of the reduction of Cr(VI) by l-methionine (represented by RSCH3) provides the rate law (45), with values for /c2... 

N-Allenylazetidinone 181 rearranges to cephalosporin 182 in the presence of lithium chloride (Eq. 13.62) [70], This is a very unusual reaction that is presumed to be initiated by chloride ion-induced cleavage of the disulfide to give sulfenyl chloride 183. Thiolate attack at the allene sp carbon atom of 183 generates ester enolate 184, which cyclizes to 182. The reactivity of the allene function in 181 ensures the success of the reaction. 

Spectral similarities between P-450 and chloroperoxidase originally led to suggestions that both enzymes had thiolate ligation [20, 22, 42]. However, the two systems displayed clear differences in their catalytic activities. Furthermore, at the time when EXAFS studies of chloroperoxidase were initiated, it was not clear whether the enzyme had a free (non-disulfide linked) cysteine available to coordinate to the heme iron [100]. Also, the unusually low pH optimum of the chloroperoxidase halogenation reaction, pH 3.0 for peroxidative formation of a carbon-halogen bond [42], raised questions concerning possible protonation of the axial heme ligand(s). 

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