[A contribution to the identification of the oral antidiabetic agent tolbutamide. 1st communication]

An identification reaction for tolbutamide given in several pharmacopoeias involves the reaction of n-butylamine, formed by acid hydrolysis of tolbutamide, with diazotised p-nitroaniline to yield a characteristic red colour of unknown structure(s). It is demonstrated that, by using TLC methods, this red colour can be separated into 8 red or yellow coloured components. The structures of these isolated compounds were determined by spectroscopical methods and, in six cases, confirmed by unequivocal synthesis. These coloured components include one pentazdiene, five triazenes and two nitro compounds.