Diisopropylethylamine → Tert-butyl 4-(6-nitropyridin-3-yl)piperazine-1-carboxylate

Participants

Reaction Steps

To a stirred solution of 5-bromo-2-nitropyridine (4.93 g, 24.3 mmol) and piperazine-1-carboxylic acid tert-butyl ester (4.97 g, 26.7 mmol) in CH3CN (60 ml) is added DIPEA (4.65 mL, 26.7 mmol). The mixture is heated at reflux for 72 hours then cooled to room temperature and the precipitated product collected by filtration. The filtrate is concentrated and purified by flash column chromatography eluting with 30% EtOAc/petrol. The combined products are re-crystallized from EtOAc/petrol to give 4-(6-nitro-pyridin-3-yl)-piperazine-1-carboxylic acid tert-butyl ester, (4.50 g, 80% yield). MS (ESI) m/z 308 (M+H)+

Provenance & Evidence