... Hz, 4H), 2. 73 -2. 83 (m, 4H), 1.18 (d, J = 6.7 Hz, 12H) 13C NMR (CDCl3, 125 MHz) δ: 163.6, 145.7, 136.8, 1 32. 6, 131 .2, 129 . 62, 129 .6, 127 .8, 126 .6, 124 .2, 124 .1, 124 .07, 122 .5, 122 .4, 29 .7, 24 .0 HR-MS ... Hz, 2H), 2. 61 -2. 71 (m, 2H), 1.14 (d, J = 6.9 Hz, 12H) 13 C NMR (CDCl3, 75 MHz) δ: 163 .2, 145.5, 136.3, 1 32. 0, 129 .8, 128 .6, 124 .1, 123 .1, 29 .2, 23 .9 HR-MS (EI): m/z = 5 12. 9939, calcd for C24H21Br2NO2: ... Hz, 12H) 13 C NMR (CDCl3, 125 MHz): δ: 186 .2, 163.1, 145.7, 136.1, 134.8, 1 32. 9, 1 32. 2, 131.1, 130.9, 130.0, 128 .1, 126 .3, 124 .2, 29 .7, 24 .0 HR-MS (ESI) : m/z = 790.3056, calcd for C52H42N2O6:...