Diethylamine → 4-(2-tert-butyl-5-nitro-1H-pyrrole-4-carbonyl)-3,3-dimethylpiperazin-2-one

Participants

Reaction Steps

To 5-tert-butyl-2-nitro-1H-pyrrole-3-carboxylic acid (100 mg, 0.47 mmol) in benzene (2 mL) was added solid PCl5 (120 mg, 0.57 mmol). The resulting reaction mixture was stirred at RT until all the PCl5 went into the solution. This reaction mixture was then added to 3,3-dimethylpiperazin-2-one (120 mg, 0.94 mmol) and diethylamine (280 ml, 0.94 mmol) in dichloromethane (DCM) (3 mL). After 30 min, the reaction was diluted with DCM (10 mL) and followed by addition of sat. NaHCO3. The organic phase was then washed with 1N HCl and brine, dried, and concentrated in vacuo. This crude product was further purified using flash chromatography (EtOAc/Hexane: 1/4) to provide 4-(2-tert-butyl-5-nitro-1H-pyrrole-4-carbonyl)-3,3-dimethylpiperazin-2-one 6 (74 mg, 49%) as yellow foam.

Provenance & Evidence