Dithizone analogs

Oxidation of dithizone (414) with selenium dioxide or iodine in water gives the disulfide (417) which then disproportionates on standing, yielding dithizone (414) and dehydrodithizone (413, R = R = Ph). This is closely analogous to the disproportionation 254 251 + 253. 

Strong nucleophilic character of dithizone could assist in the generation of such dipolar intermediates (422, 423, and 424), and there is plenty of general analogy for such intermediates. Particular reference may be made to the closely related cycloaddition reactions of meso-ionic 1,2-diazoles 373 and 382. The transformation 424 - 421 could well involve a pentacovalent phosphorane intermediate as well. 

Further, hydrazines react analogously. Thus phenylhydrazine in ether gives an almost quantitative yield of the salt of /3-phenyldithiocarbazinic acid (C6H5—NHNH—CSSH) which serves as starting material for the synthesis of dithizone.98 However, contrary to earlier statements, the azide ion adds with cyclization to thiatriazolethiones."... 

Figure 3 The procedure of Chwastowska and Kosiarska (10) for coupling diazotized aminopolystyrene with diphenylthiocarbazone (dithizone). This procedure leads to a supported diarylthiocarbazone with the indicated extra azo chromophore. An analogous procedure is used in this work to couple diazotized aminopolystyrene with di P-naphthylthiocarbazone.

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