Reaction Steps
To a stirred solution (0.04 M) of the product from example 1 step 4 and Et3N (1 eq.) in DCM/DMF (3:1) at 0° C., triphosgene (0.33 eq.) was added. The reaction mixture was stirred at 0° C. for 1 h., then, O-(tert-butyldimethylsilyl)hydroxylamine (large excess) was added and the resulting reaction mixture was stirred at RT overnight. After addition of TFA/water (1:1) and stirring of the mixture for another 4 h, the solvent was concentrated to give a crude product which was purified by RP-HPLC (Waters Symetry Prep C18, 7 micron, 19×300 mm; flow: 20 mL/min; Gradient: A: H2O+0.1% TFA; B: MeCN+0.1% TFA; 80% A isocratic for 2 min, linear to 20% A in 14 min) to yield (40%) the title compound as a solid. 1H NMR (400 MHz, DMSO-d6, 300K) δ 1H NMR (400 MHz, DMSO d6, 300K) δ 10.61 (s, 1H), 8.60 (bs, 1H), 8.51 (bs, 1H), 8.33 (s, 1H), 8.25 (bs, 1H), 8.07 (d, J=9.2 Hz, 1H), 7.97 (t, J=9.2 Hz, 2H), 7.88 (dd, J=8.4 Hz J=1.6 Hz, 1H), 7.64-7.56 (m, 2H), 7.10 (d, J=8.4 Hz, 1H), 6.69 (d, J=6.0 Hz, 1H), 6.60 (t, J=8.4 Hz, 1H), 6.59 (dd, J=8A Hz J=2.4 Hz, 1H), 5.06-4.97 (m, 1H), 3.67 (s, 3H), 3.59 (d, J=15.6 Hz, 1H), 3.51 (d, J=15.6 Hz, 1H), 3.02 (q, J=6.4 Hz, 2H), 2.31 (s, 3H), 2.06-1.90 (m, 2H), 1.50-1.16 (m, 4H). MS (ES+) C31H34N6O4 requires: 554, found. 555 (M+H)+.
