Reaction Steps
A solution containing Boc-L-alanine (69 mg, 0.37 mmol) in NMP (3 mL) was treated with HATU (131 mg, 0.34 mmol) followed by NMM (0.1 mL, 0.9 mmol) at ambient temperature. After 10 min, amine 50 (111 mg, 0.28 mmol) in NMP (5 mL) was added in a dropwise fashion. After 5 h, the reaction mixture was diluted with diethyl ether and washed successively with NaHCO3, 1 M HCl, water, and brine. The organic extract was dried over anhydrous Na2SO4, filtered and concentrated to afford 160 mg (quant.) of 51 which was used without further purification. 1H NMR (CDCl3, 300 MHz) δ7.81-7.78 (m, 1H), 7.38-7.36 (m, 1H), 7.28-7.21 (m, 3H), 6.86 (d, J=8.7 Hz, 1H), 5.04 (d, J=6.9 Hz, 1H), 4.61 (dd, J=6.3, 8.7 Hz, 1H), 4.48-4.42 (m, 1H), 4.22 (m, 1H), 4.13 (q, J=6.9 Hz, 2H), 3.73-3.62 (m, 2H), 3.41-3.36 (m, 2H), 3.28 (dd, J=3.0, 13.5 Hz, 1H), 3.11 (app t, J=6.9 Hz, 2H), 2.85-2.73 (m, 4H), 2.38 (app t, J=8.1 Hz, 2H), 2.13-1.98 (m, 2H), 1.80-1.64 (m, 1H), 1.45 (s, 9H), 1.37 (d, J=6.9 Hz, 3H), 1.26 (t, J=7.5 Hz, 3H), 1.03-0.95 (m, 6H) ppm. Mass spectrum: m/z 572 [M+H]+; and, 594 [M+Na]+.
