Structure of ‘Cystine Disulphoxide’

ALTHOUGH the reactions of aromatic ‘disulphoxides’ have been studied by Smiles and his co-workers1 and by Vinkler and Klivenyi1 among others, the structures of these compounds remained uncertain until their infra-red spectra were examined by Cymerman and Willis3. The latter work confirmed earlier evidence that the compounds hitherto known as disulphoxides should be assigned the thiolsulphonate structure (I) rather than the disulphoxide structure (II).