REACTIONS OF OXIDATION DYE INTERMEDIATES NH Resorcinol Indophenol H2N • 0 •0 Oxazine Figure 2. Co-oxidation of PPD and resorcinol (Cox) 363 intermediates only were studied, usually PPD with resorcinol, the two most common dye components. Their behavior in solution was in- vestigated at the pH, temperature, peroxide concentration, and reaction time commonly employed in hair dyeing. Also examined was the structure of a simple oxidation pigment made from PPD and resorcinol. EXPERIMENTAL Bandrowski' s Base Synthesis of BB BB was prepared (2, 3) by oxidizing a 2% aqueous PPD solution with an equal volume of 6% H202 in the presence of Na2CO• at pH 9.5 and room temperature for one day. The precipitate was filtered, dried, and recrystallized four times from nitrobenzene. The resulting crystals melted with decomposition at 243-4.5 øC in a preheated bath. A thin- layer chromatogram (see below) showed one band. Elementary analysis for C, H, N, O was correct for the molecular formula C•sH•sN6. Either ammonia or Na2CO3 could be used to adjust the pH to 9.5 the crude products were the same when compared by m.p., infrared spectrum, and thin-layer chromatogram.

864 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Formation of Bandrowski Base 0.6 0.5 0.4 •o X (m•) • •o Figure 3. Bandrowski base in oxidation mixtures. Sprectra in 0.05 21//titrate buffer, pH 2.3. -- BB standard, 1.06 X 10 -• g/ml. ß ß ß PPD oxidized, 1.08 g in 100 ml Na2CO3 at pH 9.5, with 3% H202 diluted 250-fold in buffer. - - - PPD-resorcinol, 1:1, same conditions diluted 500-fold in buffer Standard Absorption Spectrum of BB The spectrum of purified BB was obtained in 0.05 214r titrate buffer of pH 2.3 using a Bausch and Lomb Spectronic 505 spectrophotometer absorption maximum, 400 mu (very broad) molar extinction coefficient, 1(5,200 (Fig. 3). Formation of BB in Oxidation 21•ixtures PPD Alone Present.--.A 1% solution of PPD in water containing Na2COa, at pH 9.5, and H202 at 3% concentration, was stirred at room temperature for one hour. Aliquots at various time intervals were removed, diluted with 0.05 M citrate buffer (pH 2.3), and examined spectrophotometrically for the presence of BB. The absorption of these solutions exhibited a shifting maximum, closer to 380 m/•. The readings were taken at the maximum. Other Dye Intermediates Present.--Mixtures containing 1% PPD and varying amounts of a second component were allowed to react as before,