Potassium Carbonate → tert-butyl N-(2-oxocyclopentyl)carbamate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

2,2,6,6-Tetramethylpiperidine-N-oxide (2.2 g, 14.2 mmol) and potassium bromide (8.5 g, 71 mmol) are added to a solution of racemic trans-tert-butyl N-[2-hydroxycyclopentyl]carbamate (75 g, 283 mmol) in dichloromethane (285 mL). The mixture is cooled to 5° C. with stirring. A freshly prepared ice cooled (5° C.) sodium hypochlorite aqueous solution (766 mL, 566 mmol, pH adjusted to 7.5-8 by addition of 10 g of solid potassium carbonate) is added with stirring to the reaction mixture while keeping the temperature below 5° C. The mixture is stirred at 5° C. for an additional 30 min. The reaction mixture is diluted with saturated aqueous sodium chloride solution (150 mL). The organic layer is separated and evaporated. The oily red residue is purified over a silica gel pad, eluting with EtOAc/hexanes (1/3) to obtain the title compound as a cream colored solid (43 g, 76%). 1H-NMR (300 MHz, DMSO-d6) δ 6.99 (d, 1H, NH), 3.76 (q, 1H), 1.63-2.31 (m, 6H), 1.37 (s, 9H).

Herkunft & Nachweise