Hydrochloric Acid → 3,5-Diamino-2,6-dianilinopyridine dihydrochloride

Participants

Reaction Conditions

Reaction Steps

A 500 ml Parr bottle was twice charged with 2,6-dianilino-3,5-dinitropyridine (13.5 g, 0.0385 mole), 300 ml of methanol containing HCl (10 g) and 5% Pd/Charcoal catalyst (1.1 g). The mixture was placed under 55 psig. hydrogen pressure and kept at 25°-40°C until no further uptake of hydrogen was observed. The combined reduction mixtures were cooled, precipitated product and catalyst filtered under nitrogen, and the filter cake washed with 10% HCl in isopropyl alcohol. The filter cake was added to 500 ml of warm (55°C) conc. HCl, stirred well for 5 minutes, filtered and the insolubles washed with conc. HCl. The clear filtrate was cooled (0°C), diluted with 500 ml cold (-15°C) isopropyl alcohol with good stirring to precipitate product. The solid was filtered, washed with 10% HCl in isopropyl alcohol and vacuum dried over P2O5 to afford 3,5-diamino-2,6-dianilinopyridine dihydrochloride (25.5 g, 92%). Anal. Calcd. for C17H17N5.2HCl: C, 56.0; H, 5.2; N, 19.2; Cl, 19.5. Found: C, 54.0; H, 5.4; N, 19.4; Cl, 20.0.

Provenance & Evidence