4-Chlorobenzaldehyde → {1-[4-(4-Chloro-benzylamino)-benzyl]-3,5-dimethyl-1H-pyrazol-4-yl}-acetic acid

Participants

Reaction Steps

Reductive amination: To a solution of [1-(4-amino-benzyl)-3,5-dimethyl-1H-pyrazol-4-yl]-acetic acid methyl ester (intermediate 1.1.3, 100 mg, 0.37 mmol) in tetrahydrofurane (1 mL) was added 4-chlorobenzaldehyde (185 mg, 1.32 mmol) and sodium triacetoxyborohydride (240 mg, 1.13 mmol). The reaction mixture was stirred for 18 h at room temperature. The reaction mixture was filtered over Alox B, eluting with 10% methanol in dichloromethane. Saponification: After removing the volatiles under reduced pressure, the remaining residue was dissolved in methanol (1 mL) and treated with aqueous NaOH solution (4 M, 0.6 mL). After 4 h, the mixture was neutralized and purified via preparative reversed phase HPLC (gradient of methanol in water+0.1% NH3).

Provenance & Evidence