Dimethylformamide → 3,7-Diformyl-10-p-tolylphenothiazine

Participants

Reaction Steps

To 200 ml of toluene were added 20.0 g (69.1 mmol) of 10-p-tolylphenothiazine (4b), 10.0 g (73.4 mmol) of zinc chloride, and 22 ml (284.1 mmol) of DMF. The mixture was stirred, and 27 ml (289.7 mmol) of phosphorus oxychloride was gradually added thereto dropwise. The resultant mixture was reacted at 80° C. for 3 days and then poured into 300 ml of water. This mixture was neutralized with sodium carbonate, stirred at 80° C. for 2 hours, and then subjected to liquid separation. The aqueous phase was extracted with toluene three times, and the resultant organic phase collected was dried (with MgSO4) and concentrated. The residue was recrystallized twice from ethyl acetate to obtain 8.59 g of the target compound.

Provenance & Evidence