Diazonium salts, and azo

Potassium nitrite is an antidote to cyanide poisoning. It also is a vasodilator. An important application is in the dye industry to prepare diazonium salts and azo dyes. Another use is in curing certain meat products where the salt imparts an appetizing pink color to cured meats and retards microbial growth on the meat. The commerical product is usually a nitrite-nitrate mixture, containing 85% KNO2 and 15% KNO3... 

The 1,3-dipolar character of triazaallenium salts, from now on referred to as l,3-diaza-2-azoniaallene salts, is evidenced by the many [3+2] cycloaddition reactions these types of compounds can participate in. The l,3-diaza-2-azoniaallene salts are generated in situ and trapped with suitable dipolarophiles. For example, l,3-diaza-2-azoniaallene salts undergo stereospecific [3+2] cycloaddition reactions with alkynes and olefins. However, they fail to react with isocyanates, isothiocyanates and azo compounds. Also, [3+2] cycloadditions to carbodiimides and cyanamides are observed. In contrast, nitriles fail to react. 1,3-Diaza-2-azoniaallene salts are obtained in the oxidation of 1,3-disubstituted triazenes with t-butyl hypochlorite. The resultant Al-chlorotriazenes react with antimony pentachloride to form the salts as reactive intermediates. Above —25°C, l,3-diaza-2-azoniaaUene salts disproportionate into diazonium salts and azo compounds. 

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