Azo and diazo compounds

The production of aryl radicals from peroxides normally provides a cleaner method of arylation than the methods based on the decomposition of azo and diazo compounds, and, in the case of benzenoid compounds, better yields of arylated products are obtained. The... 

AZO AND DIAZO COMPOUNDS. Characteristically, these are compounds containing the group-NrN-(azo) or >N N (diazo). They arc closely related to the substituted hydrazines. The N2 group may be covalently attached to other groups at both ends, as in the azo compounds, or... 

Among the organic nitrogen compounds having nitrogen above the oxidation level of ammonia are a wide variety of substances with N-N bonds. We shall mention only a very few of the more important of these substances hydrazines, azo and diazo compounds, and azides. 

When radical anions and dianions leads to very slow SET, their nucleophilic properties have to be taken into account. Reactions of electrogenerated species toward CO2, acetic anhydride, acetic chloride, and some classic RX compounds as electrophiles can be explained on the basis of nucleophilic substitutions, but extreme cares have to be taken on the intrinsic nature of the mechanism (Sn vs. radical coupling). Thus reactions involving azo and diazo compounds in the presence of CO2 could be explained by nucleophilic addition (formation of A-functionalized azine and diazines [13]). Several reactions [15,215,229] implying CO2 and acetic anhydride [230] were described. 

Nitrogen screening constants of some azo and diazo compounds in ppm, referred to external... 

This chapter describes photoreactions of nitrogen containing chromophores which are different from the principal reactions of electronically excited carbonyl compounds. Five groups of substrates were included cyclic and acyclic imines, nitriles, amine oxides, azo and diazo compounds, and enamides. 

There is now abundant evidence for the homolytic decomposition of covalent azo- and diazo-compounds of many types, but evidence for one-electron transfer reactions of diazonium salts is very scanty. Cooper (4) and Marvel ( ) have shown that reduction of diazonium salts by ferrous ions can initiate.vinyl polymerization, while Kornblum s work ( ) has shown that the reduction of diazonium salts by hypophosphite is promoted by oxidizing agents in a manner indicative of the chain reaction ... 

You met diazonium salts in Chapter 22. Arene diazonium salts are stable compounds, but alkyl diazonium salts, which are formed by protonation of diazo compounds, are not. They decompose rapidly with loss of N2—this was how the carboxylic acid got methylated at the beginning of the chapter. Other relatives of the azo and diazo compounds are alkyl azides. Alkyl azides have three nitrogen atoms and are usually stable but azides of low molecular weight may explode on impact or heating. 

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