Aryl azides from diazonium compounds

Table 11. Synthesis of aryl azides from diazonium compounds and...

Aryl substrates containing suitable leaving and activating groups react readily with moderately strong nucleophiles such as azide ion and a number of aromatic azides have been prepared in this manner (Table 4). Such Ar reactions complement the synthesis of aromatic azides from diazonium compounds zind are of particular value in forming azides of heteroaromatic systems in which dizizotization procedures are unsatisfactory,... 

The successful synthesis of these compounds showed the feasibility of using the carbodiimidazole coupling reaction in the formation of aryl-azido ATP analogs. For the general synthesis of the arylazidocarboxylic acids, 4-fluoro-3-nitroaniline is first diazotized in a concentrated hydrochloric acid medium in the presence of sodium nitrite [Eq. (2)]. The diazonium salt is subsequently treated with sodium azide, which results in the formation of a light-sensitive 4-fluoro-3-nitrophenyl azide (IV) [Eq. (3) ]. The structure of (IV) has been confirmed by its melting point of 52°-52.5° (recrystallized from petroleum ether) its NMR spectrum, 7.47 ppm (2 protons), 7.78 ppm (1 proton) and its mass spectrum, m/e 182. 

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