Hydrazodicarboxylic acid

Oxidation of various nitrogen compounds. Primary aromatic amines are oxidized slowly to azobenzenes in yields on the order of 40-50%. Esters of hydrazodicarboxylic acid are oxidized rapidly and in high yield in refluxing... 

Ring closures via N,N -dicarbalkoxy-N-methylenehydrazinium salts Cyclic hydrazodicarboxylic acid esters... 

Diacyloxamides, unsym. Dinitromethylene compds. Hydrazodicarboxylic acid esters... 

A new one-pot synthesis of azo-compounds from hydrazodicarboxylic acid esters appears to be an improvement over existing methods for the same transformation. Cleavage of (54) with lithium methyl mercaptide and subsequent oxidation with aqueous potassium ferricyanide at 0 °C gives the azo-compound (55) in 82% yield (Scheme 34). 

The reaction of a pyridazine, 5 dicarboxylic acid derivative with hydrazine remains a favored approach for the preparation of pyridazino[4,5-4 pyridazines <2000TL2863, 2002JCCS217>, and di- /t-butyl hydrazodicarboxylate has been used as a hydrazine substitute in the presence of perhydro derivatives, as illustrated in Equation (6) <1993JPC13408>. 

In a 500-mL, three-necked flask equipped with mechanical stirrer, thermometer, pressure-equalizing dropping funnel, and gas outlet tube is added 78.55 g (0.21 mol) of bis(2,2,2-trichloroethyl) hydrazodicarboxylate dissolved in 180 mL of chloroform (Note 6). The solution is cooled to 0°C and 53.2 mL (1.26 mol) of fuming nitric acid (Notes 7 and 8) is added so that the temperature of the solution does not rise above 5°C. The reaction mixture is then allowed to warm slowly to room temperature over 4 hr (Note 9). After an additional 2 hr at room temperature, the material is transferred to and shaken in a 1-L separatory funnel half filled... 

Bis(2,2,2-trichloroethyl) hydrazodicarboxylate 1,2-Hydrazinedicarbox-ylic acid, bis(2,2,2-trichloroethyl) ester (9) (38858-02-5)... 

Diethyl and di-ter/-butyl hydrazodicarboxylate are dehydrogenated to diethyl- and di-tert-butylazodicarboxylate, respectively, by nitric acid [1184] and by iV-bromosuccinimide [1185] (equation 493). 

It is decomposed by hydrochloric acid into ethyl hydrazodicarboxyl-ate, mercuric chloride, carbon monoxide, and alcohol by piperidine into ethyl hydrazodiearboxylate, mercury, and piperylurethane by bromine into ctliyl azodicarboxylate, mercuric bromide, and ethyl bromoforni ate. 

Ethyl hydrazodicarboxylate can be prepared by the reaction of ethyl chloroformate with hydrazine hydrate or hydrazine sulfate in the presence of potassium hydroxide. It can be prepared also by the treatment of symmetrical hydrazinedicarboxylic acid diazide with ethyl alcohol. ... 

Ethyl azodicarboxylate can be prepared by treating ethyl hydrazodicarboxylate with concentrated nitric acid or a mixture of concentrated and fuming nitric acid. ... 

Dehydrogenation and Aromatization. Dihydropyridines can be aromatized by dilute nitric and sulfuric acid (eq 18). Diethyl hydrazodicarboxylate is dehydrogenated by fuming nitric acid to diethyl azodicarboxylate in 70-80% yield. ... 

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