Reaction Steps
From acid 18i with a reflux time of 48 h and a recharge with an equal amount of CDI after 24 h, and obtained as a yellow solid (79%), mp 214-215° C. (from acetonitrile). 1H NMR (CDCl3): δ 1.28 (t, J=7.2 Hz, 3H, CO2CH2CH3), 2.29 [s, 6H, N(CH3)2], 2.62 (t, J=6.4 Hz, 2H, CH2CH2NMe2), 2.87 (s, 3H, ArCH3), 3.72 (q, J=5.9 Hz, CH2CH2NMe2), 4.25 (q, J=7.1 Hz, CO2CH2CH3), 4.78 (s, 2H, CH2CO2Et), 7.51 (t, J=7.6 Hz, 1H, H-8), 7.74 (d, J=6.9 Hz, 1H, H-7), 7.87 (d, J=8.2 Hz, 1H, H-9), 8.53 (s, 1H, H-3), 9.28 (s, 1H, H-10), 10.96 (br t, J=4.8 Hz, 1H, CONH). 13C NMR (CDCl3): δ 13.7 (CO2CH2CH3), 18.1 (ArCH3), 37.3 (CH2CH2NMe2), 45.1 [N(CH3)2], 50.1 (CH2CO2Et), 58.4 (CH2CH2NMe2), 61.6 (CO2CH2CH3), 109.8 (C-4), 118.7 (C-10a), 125.5 (C-9a), 126.4 (CH, C-8), 126.9 (CH, C-9), 132.6 (CH, C-7), 135.6 (C-6), 139.6 (CH, C-10), 142.7 (CH, C-3), 147.8 (C-5a), 148.4 (C-4a), 162.0 (C-1), 163.9 (CONH), 166.9 (CO2Et).
