Oxidation kinetics of an antiasthmatic, 2-[(4-hydroxyphenyl)amino]-5-methoxybenzenemethanol, and stabilization with ascorbic acid.

A novel antiasthmatic, 2-[(4-hydroxyphenyl)amino]-5-methoxybenzenemethanol (1), oxidizes to the corresponding iminoquinone in aqueous solutions. The reaction was monitored by a paired-ion reversed-phase HPLC method. The oxidation rate was highly dependent on the solution pH, with a large rate increase occurring above pH 6.1. In nonaqueous solution, the oxidation reaction was significantly slower. Ascorbic acid protects 1 from oxidation. The aqueous solution of the decomposed product is reduced to 1 in the presence of ascorbic acid.