Reaction Steps
To a solution of 244 (467 mg, 1.5 mmol) in DCM (10 ml) was added triethyl amine (0.42 ml) and 3,4,5-trimethoxybenzoyl chloride (520 mg, 2.3 mmol). The reaction mixture was stirred at rt for 21 h. TLC analysis indicated the presence of starting material so the reaction mixture was heated in the microwave for 5 min at 60° C. and for 15 min at 80° C. A further 0.5 eq of benzoyl chloride was added and the reaction mixture was heated in the microwave at 80° C. for 15 min. Water (20 ml) was added, the layers separated and the aqueous layer extracted with DCM (3×60 ml). The combined organic phases were washed with sat. aq. sodium hydrogen C(Ar)bonate (60 ml) and brine (60 ml), dried (MgSO4) and concentrated in vacuo. Purification (flashmaster: 20 g, EtOAc/hex then Hex/DCM) afforded the title compound (440 mg, 58%) as a colourless foam. mp 175-177° C. 1H NMR (270 MHz; CDCl3) 1.32 (3H, d, J=6.9 Hz, CH3CH), 1.39 (3H, s, CH3), 1.87 (3H, s, CH3), 2.53 (1H, d, J=15.3 Hz, one of CH2), 3.27 (1H, d, J=15.3 Hz, one of CH2), 3.82 (6H, s, 2×OCH3), 3.86 (3H, s, OCH3), 3.88 (3H, s, OCH3), 4.69 (1H, q, J=6.9 Hz, CHCH3), 5.04 (2H, ABq, J=12.1 Hz, CH2Ph), 6.47 (3H, s, 3×CH), 6.75 (1H, s, CH), 7.25-7.41 (5H, m, 5×CH, phenyl). 13C NMR (100 MHz; CDCl3) 23.43 (CH3), 25.28 (CH3), 29.40 (CH3), 44.18 (CH2), 56.18 (4×OCH3), 57.68 (C), 60.92 (CH), 71.38 (CH2), 102.51 (CH), 111.45 (CH), 112.36 (CH), 127.09 (C), 127.28 (CH), 127.87 (CH), 128.49 (CH), 130.61 (C), 135.07 (C), 136.09 (C), 137.89 (C), 146.88 (C), 149.06 (C), 153.41 (C), 170.97 (C). LC/MS (ES+) tr=1.03 min, m/z 528.27 (M++Na). HPLC tr=2.38 min (>99%). Anal. Calcd. for C30H35NO6: C 71.27, H 6.98, N 2.77. Found: C 71.1, H 6.99, N 2.70%.
