Diazotization, defined

There is little or no well-defined chemistry of 2-amino-pyrones, -pyrylium salts, etc., because of the ease with which these systems undergo ANRORC reactions to give substituted pyridones (equation 88). 4-Aminopyrylium salts are reversibly deprotonated to the imines (equation 89). Amino groups in the 3- and 5-positions of pyrones can be diazotized normally. 

Methods for Determining Biomarkers of Exposure and Effect. No biomarker has been identified that can be quantitatively related to dinitrophenol exposure (see Section 2.5.1) however, the presence and the amount of 2,4-DNP and 2-amino-4-nitrophenol, a metabolite in the urine, can be used as rough indicators of the intensity of exposure (see Section 2.5.1). The methods presently available for determining 2,4-DNP and 2-amino-4-nitrophenol (diazotization) in urine are outdated (Gisclard and Woodward 1946). An enzyme-linked immunosorbent assay (ELISA) is available for the quantitation of 2-amino-4-nitrophenol in water samples, but is not effective in urine (Li et al. 1991). It would be useful to develop an updated routine method for determining 2,4-DNP, 2-amino-4-nitrophenol, and 4-amino-2-nitrophenol in urine with well-defined detection limits, precision, and accuracy. 

Having understood the various steps that are involved in the diazotization process, one may define it as— A chemical interaction whereby an aromatic primary amine, having amino (-NH ) function directly attached to the nucleus, upon treatment with nitrous acid in cold (0— 5°C) yield diazonium salts. ... 

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