The Reaction of Quinone and Sulfite. I. Intermediates¹

Effect of Bisulfite on Lobster Shell Phenoloxidase

“…However, they did not scan at 340-360 nm. Mixtures of psulfoquinones and sulfite have been reported to have absorption maximum of 320-345 nm depending on the pH of the mixture (LuValle, 1952). Our results also showed that bisulfite was able to bleach the violet color of melanochrome, an intermediate colored compound formed in the pathway behveen dopachrome and melanin.…”

Free-radical chemistry of sulfite.

“…With pyridine this leads to formation of N-pyridinium sulfonate (19). The reaction of hydroquinone with sulfite in the presence of oxygen is perhaps the most studied (20,21), since sulfite was used as a preservative in hydroquinone-based photographic developers (22). In this system two types of reaction appear to take place: (a) oxidation of the hydroquinone by sulfite radicals and by molecular oxygen, and (b) sulfonation of the quinone to form hydroquinone sulfonates (followed by oxidation ofthe latter to quinone sulfonates) (21).…”

Amines as leaving groups in nucleophilic aromatic substitution reactions

“…Most rate data regarding reactions where an amino group in an aromatic ring is displaced by a nucleophile were obtained as secondary reactions in other studies. 4 The low reactivity of compounds of the type 2 toward attack at carbon 1 is considered to be a consequence of the interaction of the lone pair of electrons on the nitrogen (2) Buncel, E.; Norris, A. R.; Russell, K. E.; Sheridan, P. J. Con. J. Chem.…”