Acetic Acid → 4-(3-chloro-phenylamino)-3-(3,5-dimethoxybenzylamino)-1H-pyrazolo[3,4-d]pyrimidine

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Reaction Steps

99.7 mg (0.60 mmol) of 3,5-dimethoxy-benzaldehyde are added to a solution of 130 mg (0.50 mmol) of 3-amino-4-(3-chloro-phenylamino)-1H-pyrazolo[3,4-d]pyrimidine in 26 ml of methanol and 120 mg (2.0 mmol) of acetic acid. As the reaction mixture is stirred, a solid precipitates which can be dissolved again by the addition of 52 ml of DMEU. 220 mg (3.5 mmol) of NaCNBH3 are added thereto and stirring is then continued for 5 hours at RT. Since not all of the 3-amino-4-(3-chloro-phenylamino)-1H-pyrazolo[3,4-d]pyrimidine has been reacted (HPLC), 220 mg of NaCNBH3 are added twice more and stirring is continued for 5 hours each time. The reaction solution is then poured into 1 liter of water, stirred vigorously for 1 hour and filtered. Crystallization of the filtration residue from acetone yields 4-(3-chloro-phenylamino)-3-(3,5-dimethoxybenzylamino)-1H-pyrazolo[3,4-d]pyrimidine; m.p. 208-209° C.; HPLC: TRet (Grad20-100)=11.7; FAB-MS: (M+H)+ =411.

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