D 2501 (OTTO) 2,3-Diaminopyridine, 97% Cas 452-58-4 - used in the synthesis of 2,3-diaminopyridinium-4-hydroxybenzoate. D 2501 (OTTO) 2,3-Diaminopyridine, 97% Cas 452-58-4 - used as internal standard in analysis of poly(amidoamine)dendrimers having different terminal functionalities by capillary electrophoresis.