Potassium Carbonate → 4-[4-(4-Benzyloxycarbonylaminobutyl)phenoxy]-2-tert-butoxycarbonylamino-butyric acid methyl ester

Participants

Reaction Conditions

Reaction Steps

Potassium carbonate (935 mg, 6.77 mmol) was added in one portion to a solution of 4-[4-(benzyloxycarbonylamino)butyl]phenol (506 mg, 1.69 mmol) and N-Boc bromide 19 (501 mg, 1.69 mmol) in anhydrous DMF (10 mL). The reaction mixture was stirred at 70° C. (oil bath) for 14 h, cooled to room temperature, and diluted with ethyl acetate (100 mL) and hexanes (20 mL). The mixture was washed with water (4×20 mL) and brine (40 mL) and concentrated under reduced pressure. Flash silica gel column chromatography using ethyl acetate/CH2Cl2 (1:25, 1:20, v/v) gave the desired product 20 as a thick yellow oil (718 mg, 83% yield). 1H NMR (300 MHz, CDCl3) δ 1.44 (s, 9H), 1.48-1.68 (m, 4H), 2.12-2.38 (m, 2H), 2.48-2.60 (m, 2H), 3.10-3.24 (m, 2H), 3.75 (s, 3H), 3.97-4.06 (m, 2H), 4.41-4.52 (m, 1H), 4.70 (br s, 1H), 5.09 (s, 2H), 5.25-5.37 (m, 1H), 6.70-6.80 (m, 2H), 6.95-7.09 (m, 2H), 7.30-7.38 (m, 5H). m/z (ESI) 515 [C28H38N2O7+H]+.

Provenance & Evidence