2-Nitrobenzoyl chloride → 3-(2-Nitro-benzoylamino)-furo[3,2-c]pyrazole-1,5-dicarboxylic acid 1-ethyl ester 5-propyl ester

Participants

Reaction Steps

To a solution of 3-amino-furo[3,2-c]pyrazole-1,5-dicarboxylic acid 1-ethyl ester 5-propyl ester (500 mg, 1.606 mmol) and diisopropylethylamine (DIEA, 0.824 mL, 4.818 mmol) in tetrahydrofuran (THF, 20 mL) at 0° C., 2-nitro-benzoyl chloride (0.318 mL, 2.409 mmol) was added. The reaction mixture was kept at the same temperature for 10 minutes then allowed to reach room temperature and let react overnight. The solvent was removed under vacuum, the residue was dissolved in dichloromethane (DCM) and washed with a 10% solution of acetic acid (AcOH), water, saturated NaHCO3 and brine. The crude was purified on silica gel (eluant dichloromethane/methanol 96/4) yielding 512 mg (69%) of the title compound.

Provenance & Evidence