Ethyl Acetate → 3-benzylamino-4-(3-chloro-phenylamino)-1H-pyrazolo[3,4-d]pyrimidine

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Reaction Conditions

Reaction Steps

With the exclusion of moisture, 79.2 g (295 mmol) of N′-(3-benzylamino-4-cyano-1 H-pyrazol-5-yl)-N,N-dimethyl-formamidine are suspended in 700 ml of methanol; 60.6 g (369 mmol) of 3-chloro-aniline hydrochloride are added and the mixture is boiled under reflux for 22 hours. The resulting yellow reaction solution is cooled to 50° C. and poured into 2 liters of ice-water, 200 ml of sat. NaHCO3 solution and 1 liter of ethyl acetate. The aqueous phase is separated off and extracted twice with ethyl acetate. The organic phases are washed twice with water, sat. NaHCO3 solution, water and brine, dried (Na2SO4) and concentrated by evaporation to a residual volume of ≈1.5 liters. Seeding and dilution with 300 ml of diethyl ether yield crystalline 3-benzylamino-4-(3-chloro-phenylamino)-1H-pyrazolo[3,4-d]pyrimidine; m.p. 214-217° C.; TLC: Rf=0.29 (ethyl acetate:hexane=1:1).

Provenance & Evidence