Methyl red was first prepared[1] by diazotization of anthranilic
acid in alcoholic solution, the product being allowed to react with
dimethylaniline in the same solvent. It has been stated[2] that this
process does not work satisfactorily and yields a different product,
of brownish-red color.
The preparation of methyl red in aqueous solution has been
described by two workers, one of whom[3] gives but few details
and claims a nearly quantitative yield; the other[4] gives fuller
details and states the yield to be 43.1 per cent of the theory.
The recrystallization of methyl red from toluene is stated[5]
to yield a product melting at 183'0.
[1] Ber. 41, 3905 (1908).
[2] Chem. Zentr. 1910, (1), 960; 1910, (11), 1561.
[3] J. Chem. Soc. 97, 2485 (1910).
[4] C. A. 14, 3406 (1920)
[5] J. Chem. Soc. 99, 1334 (1911).