Ammonium Chloride → [4-(4-Hydroxy-tetrahydro-pyran-4-yl)-phenyl]carbamic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

THF (50 mL) in an oven-dried 500 mL single neck flask was cooled in −78° C. bath under N2. A solution of n-butyllithium in hexanes (15.4 mL, 2.5 M, 38.6 mmol) was added dropwise via syringe over 10 min. The clear solution was stirred at −78° C. for 30 min. N-Boc-4-bromoaniline (5.00 g, 18.4 mmol), dissolved in 10 mL THF, was added dropwise over 10 min with stirring then stirred a further 30 min at −78° C. Tetrahydro-4H-pyran-4-one (2.02 g, 20.2 mmol) in 5 mL THF added was dropwise over 10 min. After 150 min, the reaction mixture was allowed to warm to RT then added to 200 mL saturated NH4Cl and extracted with ether (3×100 mL). The combined organic layers were washed with water (50 mL) and brine (50 mL) and dried over MgSO4. Filtration and concentration provided the crude product that was recrystallized from 70 mL DCM to give the purified product as a white solid (2.29 g, 42%). MS (ESI): mass calcd. for C16H23NO4, 293.3; m/z found, 276.1 [M−H2O+H]+. 1H NMR (500 MHz, CDCl3): 7.46-7.38 (m, 2H), 7.36 (d, J=8.6 Hz, 2H), 6.48 (s, 1H), 3.90 (m, 4H), 2.30-1.98 (m, 2H), 1.68 (d, J=12.1 Hz, 2H), 1.52 (s, 9H).

Provenance & Evidence