Reactions of Disulphides and Polysulphides

Nogami, J. Hasegawa, N. Ikari, K. Takeuchi, and K. Ando, Chem. and Pharm. 

Di-(2-pyridyl) disulphide has found a novel use as oxidant in peptide synthesis iV-benzoyl-L-leucine is coupled to glycine ethyl ester to give the protected dipeptide, when triphenylphosphine and the disulphide are added, formation of triphenyl phosphite and pyridine-2(li7)-thione balancing the equation.  

Insertion reactions are particularly unprofitable for disulphides and diazomethane, though under irradiation moderate yields may be obtained (RSSR + CH2N2 RSCHjSR 4- N2). Diselenides give quantitative yields under these conditions, and ditellurides are easily inserted, in a dark 

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