Acetone → 2-(N-isopropylamino)-4-methylbenzophenone

Participants

Reaction Conditions

Reaction Steps

422.6 g. (2 moles) of 2 amino-4-methylbenzophenone is dissolved in 2.34 liters (40.29 moles) of acetone, and with stirring 540 gms (3.25 moles) of o-phthalic acid is added. To the resulting suspension is added portionwise 80 gms (2.14 moles) of sodium borohydride over a period of 45 minutes and in a manner such as to keep the reaction mixture at 20°-25° C. At the end of the addition, the cooling is altered such as to allow the temperature to rise to 30°-35° C., and this temperature is maintained for 30 minutes. The cooling is removed and the temperature carefully increased to 50° C., and regulated at 50°-55° C. for 90 minutes. The mixture is then cooled to 15° C., 808 gms of 8% aqueous NaOH (1.625 moles) is added, the phases separated and the acetone phase (upper layer) recovered and concentrated. The water layer is extracted with 1 litre of heptane, and the concentrated acetone phase added to the heptane extract. The heptane solution is washed with 250 mls of H2O, then concentrated by distillation to obtain 496 gms of 2-(N-isopropylamino)-4-methylbenzophenone, b.p. 180°-185° C./5mm (Yield 99%).

Provenance & Evidence