Cesium carbonate → (S)-tert-Butyl 3-Ethyl-4-(6-nitropyridin-3-yl)piperazine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

A 250-mL single-neck round-bottomed flask equipped with a magnetic stirrer and a reflux condenser was charged with 1,4-dioxane (50 mL), 5-bromo-2-nitropyridine (2.02 g, 10 mmol), (S)-tert-butyl 3-ethylpiperazine-1-carboxylate (2.14 g, 10.0 mmol), Pd2(dba)3 (458 mg, 0.50 mmol), XantPhos (576 mg, 1.0 mmol), and cesium carbonate (6.52 g, 20 mmol). After three cycles of vacuum/argon flush, the mixture was heated at 100° C. overnight. After this time the reaction was cooled to room temperature. It was then filtered and the filtrate was evaporated under reduced pressure. The residue was purified by silica-gel column chromatography eluting with 3:1 petroleum ether/ethyl acetate to afford 111a (700 mg, 22%) as a yellow solid. MS: [M+H]+ 336

Provenance & Evidence