Heating p-toluidine hydrochloride in tert-butanol gave a crystalline precipitate of N-tert-butyl- p-toluidine hydrochloride. This compound, now readily available by this simple procedure, was used to make mauveine, which was found by TLC analysis to be identical to authentic mauveine.
The compositions of modern mauveines I and II made using tert-butyl-p-toluidine are analysed by HPLC and compared with authentic mauveine and a standard consisting of mauveine A, B2, B and C. The composition of modern mauveine II is similar to that of authentic mauveine.