Dichloromethane → Sodium Carbonate

Participants

Reaction Steps

Coupler F (5.65 g, 20.98 mmol) was stirred vigorously for 15 minutes with 300 ml dichloromethane. Blocked developer 1-n-butyl-3-(4'-N,N-diethylamino)phenyl urea (5.194 g 19.72 mmol) was ground to a fine powder in a mortar and added to the reaction mixture. A solution of sodium carbonate (40 g, 378.94 mmol) in 800 ml of water was prepared. A solution of potassium ferrocyanide (15.08 g, 35.70 mmol) and potassium ferricyanide (1.32 g, 4.0 mmol) in 20.0 ml water was prepared. The sodium carbonate solution was added to the reaction mixture and the dropwise addition of the potassium ferrocyanide/potassium ferricyanide solution was begun immediately and continued over a 15 minute period. The mixture was stirred an additional 15 minutes and potassium ferricyanide (1.32 g, 4.0 mmol) was added. The mixture was stirred an additional 20 minutes and potassium ferricyanide (2.6 g, 8.0 mmol) was added. The mixture was stirred an additional 25 minutes and potassium ferricyanide (2.6 g, 8.0 mmol) was added. The mixture was stirred an additional 25 minutes and potassium ferricyanide (2.6 g, 8.0 mmol) was again added. The aqueous phase was separated and the organic phase was washed twice with saturated sodium chloride solution. The organic phase was dried over magnesium sulfate, filtered and the solvent was removed in vacuo. The crude product residue was purified by chromatography on a Waters Prep 500 HPLC using a 4:1 dichloromethane/ethyl acetate solvent system to give yellow leuco dye G contaminated with some 3-butyl-1-[4'-N,N-diethylamino-2'-(2-benzoyl-o-methoxyacetanilidyl)]phenyl urea.

Provenance & Evidence