Addition of sulfur compounds

MA and its derivatives react readily with thiols to yield addition products. A number of sulfur compounds have been examined and many additions involving apparently complex molecules can be rationalized in terms of the addition of the S-H bond or S anion. In many cases studied, nucleophilic addition appears to be the mode of reaction. The yields, as we shall see, are so high that the reaction of thiols with MA has been used to estimate relative nucleophilicities of the thiols. However, before generalizing, one should be cautioned that reactions in the absence of a catalyst and with peroxide catalyst have been reported. 

Addition of benzyl mercaptan 23 was reported by Szabo and Stille/ employing the triton B catalyst to yield benzylthiosuccinic anhydride 24. 

Maleic acid readily adds thiols in aqueous solutions using an alkali catalyst. Esters of maleic also undergo similar additionwith sodium alcoholate or amine as a catalyst. Thioglycolic acid 27 also adds to disodium maleate giving quantitative yields of the tricarboxylic acid derivative 28.  

Mulvaney et al. have prepared esters of carbomethoxymercapto-succinic acid by employing one of the three routes shown below. This suggests the versatility possible with these compounds. (DMM = Dimethylmaleate.) 

Thiolacetic acid 33 can also add to MA to give 34 in an 83% yield. Brown et employed a peroxide catalyst for this reaction. 

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Addition of Sulfur Compounds (Addition of Halogen, Sulfur)... 

Permanent hair dyes also include metal salt dyes, which produce a finely dispersed metal deposit on the hair. Metal oxides or sulfides may also be formed this process can be promoted by the addition of sulfur compounds [9, p. 240], A... 

AFM and XPS data for model Pd supported catalysts show that the morphology of these catalysts are greatly affected by reduction in hydrogen and by addition of sulfur compounds to the surface... 

The addition of sulfur compounds to a solution of TiCl4 in 1,2-di-chloroethane or toluene causes a color change from yellow to brown, indicative of complex formation. The addition of aluminum alkyl produces a further deepening of the color but the solution remains transparent no Ti(IlI) is formed. Although the structure of the active catalyst species is not yet known, it is reasonable to assume that all three components form part of it... 

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