1,2-Diarylethylenediamines as fluorogenic reagents for catecholamines

Twenty-eight 1,2-diarylethylenediamines were investigated in a search for highly sensitive fluorogenic reagents for catecholamines (norepinephrine, epinephrine and dopamine). They all react with epinephrine used as a model catecholamine under mild conditions (pH 6.5–6.8, 37–50°C) in the presence of potassium hexacyanoferrate (III) to produce fluorescence. Of the compounds tested, 1,2-bis(3,4-dimethoxyphenyl)ethylenediamine, 1,2-bis(4-methoxyphenyl)ethylenediamine and 1,2-bis (4-ethoxyphenyl)ethylenediamine, all in the meso-form, are the most sensitive for all the catecholamines. 1,2-Diphenylethylenediamine, 1,2-bis(4-methoxyphenyl)ethylenediamine and 1,2-bis (4-methylphenyl) ethylenediamine in the dl-form are more sensitive to dopamine than the corresponding compounds in the meso-form. Catecholamines can be determined at concentrations as low as 10–15 pmol ml^?1 by using those compounds as reagents. The reactions of other catechol compounds are reported. Other types of biologically important compounds do not interfere.