Arenes with arylhydrazines

Free-radical arylations of arenes with arylhydrazines and arylboronic acids... 

Free-radical arylation of arenes with arylhydrazines Preparation of 2-(4-bromophenyl)furan (539) (8/... 

Another way of making arylhydrazines is the electrophilic amination of electron-rich arenes with an azodicarboxylate. ... 

TosN, (0.37 g, 2 mmol), the arylhydrazine (2 mmol), and TEA-Br (0.1 g, 0.5 mmol) in xylene (10 ml) are added to aqueous NaOH (50%, 10 ml) and the mixture is refluxed until the azide has been fully consumed (2-10 h). The organic phase is separated and the aqueous phase is extracted with PhH (3 x 10 ml). The combined organic solutions are dried (MgS04) and evaporated to yield the arene [e.g. PhH 40% (6 h) pyridine 98% (6 h) from 2-hydrazino derivative pyridazine 79% (8 h) from 3-hydrazino derivative)]. 

Bis[4-methoxyphenyl] tellurium oxide was found to be a mild and highly selective oxidizing agent for the conversion of thiocarbonyl groups to carbonyl groups, thiols to disulfides, arylhydrazines to arenes, and 1,2- or 1,4-dihydroxyarenes to quinones. No reaction was observed with simple phenols, alcohols, enamines, amines (including pyrrole, indole, tryptophan, tyrosine, aniline, and dimethylaniline), oximes, dithiolanes, isonitriles, and 2,4-dinitrophenylhydrazones4. 

Arylamines. Electron-rich arenes react with bis(2,2,2-trichloroethyl) azodicar-boxylate to give arylhydrazine derivatives in good yields. Reduction with Zn-HOAc provides the amines in one operation. For example, p-methoxyaniline is prepared in about 70% yield. 

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