Electron-transfer reduction of 1-deoxy-1-nitroalditols to glycamines with ferrous hydroxide

Treatment of eight different 1-deoxy-1-nitroalditols with freshly prepared ferrous hydroxide at ambient temperature provides the corresponding glycamines that were isolated in 81–94% yields as salts with TFA. Under such modified reaction conditions, the retro-Henry reaction of the starting compounds is significantly suppressed due to the amphoteric character of the reducing agent in water. Lower, 58–75% yields were obtained by the classical process with ferrous sulfate in aqueous ammonia and employing an improved purification procedure for the product glycamines by irreversible capture of sulfate ions with barium carbonate.