Reaction Steps
To a stirred solution of 2-(4-chloromethyl-phenoxy)-benzothiazole (15.3 g, 55.3 mmol) and (S,S)-2,5-diaza-bicyclo[2.2.1]heptane-2-carboxylic acid tert-butyl ester (13.2 g, 66.4 mmol) in CH3CN (200 mL) was added triethylamine (Et3N) (11.5 mL, 82.9 mmol). The resulting solution was stirred at rt for 24 h and then concentrated. The crude residue was then partitioned between CH2Cl2 (800 mL) and saturated (satd.) aqueous (aq.) NaHCO3 (200 mL). The organic layer was separated, dried (Na2SO4), filtered and concentrated. Purification by silica gel flash chromatography (10% to 40% ethyl acetate (EtOAc) in hexanes) afforded the title compound as a white foam (17.2 g, 71%). MS (ESI): mass calcd. for C24H27N3O3S, 437.18; m/z found, 438.2 [M+H]+. 1H NMR (500 MHz, CDCl3, mixture of rotamers): 7.73 (d, J=7.1 Hz, 1H), 7.66 (d, J=7.1 Hz, 1H), 7.42 (d, J=8.1 Hz, 2H), 7.38 (m, 1H), 7.32-7.24 (br m, 3H), 4.40 (br m, 0.5H), 4.26 (br m, 0.5H), 3.76 (br d, J=9.7 Hz, 2H), 3.63 (br d, J=10.5 Hz, 0.5H), 3.50 (br m, 1H), 3.46 (m, 0.5H), 3.18 (br m, 1H), 2.93 (br d, J=8.8 Hz, 0.5H), 2.88 (br d, J=9.4 Hz, 0.5H), 2.73 (br d, J=9.2 Hz, 0.5H), 2.55 (br d, J=9.2 Hz, 0.5H), 1.87 (br t, J=8.8 Hz, 1H), 1.74 (br d, J=9.3 Hz, 0.5H), 1.68 (br d, J=9.3 Hz, 0.5H), 1.47 (s, 9H).
