Benzenesulfonyl chloride → [1-(4-Benzenesulfonylamino-benzyl)-3,5-dimethyl-1H-pyrazol-4-yl]-acetic acid

Participants

Reaction Steps

Sulfonamide formation: To a solution of [1-(4-amino-benzyl)-3,5-dimethyl-1H-pyrazol-4-yl]-acetic acid methyl ester (intermediate 1.1.3, 54 mg, 0.20 mmol) in dichloromethane (1 mL) was added triethylamine (72 μL, 0.51 mmol) and phenylsulfonyl chloride (36 μL, 0.25 mmol). The reaction mixture was stirred for 1 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 (0.5 mL) and treated with aqueous LiOH solution (1 M, 0.4 mL). After 1.5 h, the mixture was neutralized and purified via preparative reversed phase HPLC (gradient of methanol in water+0.1% trifluoroacetic acid).

Provenance & Evidence