J = 8 Hz, 1H), 4.52 (m, 1H), 4.42 (m, 1H), 4.24 (dd, J = 8, 20 Hz, 1H), 4.12 (dd, J = 8, 20 Hz, 1H), 3.87 (s, 3H), 3.09 (m, 2H), 2.25 (m, 1H), 2.06 (m, 1H), 1.93 (m, 1H), 1.80 (dd, J = 8, 16 Hz, 1H), 0.93 (s, 9H); MS (ESI+) for C25H34N4O6m/z 487.2 (M + H)+; anal. calcd for C25H34N4O6·0.3 H2O: C, 61.03; H, 7.09; N, 11.39. Found: C, 61.07; H, 7.09; N, 11.22; HRMS (ESI+) calcd for C25H34N4O6 487.2551, found 487.2541.

4-Methoxy-N-((1S)-1-{[((1S)-3-methoxy-2-oxo-1-{[(3S)-2-oxopyrrolidin-3-yl]methyl}propyl)amino]ca