Reaction Steps
THF (8 mL) then HCO2N4 (0.23 g, 3.6 mmol) in H2O (1 mL) were added to cooled (0° C.) mixture of 17b (0.20 g 036 mmol) and 10% Pd/C (0.1 g) under N2. The mixture was stirred at 0° C. for 14 h, and was then filtered through Celite. The Celite was washed with CH2Cl2/H2O. The aqueous layer was extracted with CH2Cl2(×3). The CH2Cl2 extracts were dried (brine, Na2SO4) and passed through a short plug of silica gel to give 18b (0.16 g, 93%) as a yellow solid: mp 209–215° C.; 1H NMR [(CD3)2SO]δ 11.66 (s, 1 H), 10.02 (bs, 1 H), 8.76 (dd, J=4.1, 1.4, 1 H), 8.41 (dd, J=8.5, 1.3, 1 H), 8.07 (s, 1 H), 7.56 (dd, J=8.5, 4.1, 1 H), 7.40 (d, J=8.9, 1 H), 7.17 (d, J=2.2, 1 H), 7.11 (d, J=1.2, 1 H,) 6.93 (dd, J=8.9, 2.3, 1 H), 4.82 (dd, J=10.7, 9.6, 1 H), 4.57 (dd, J=11.0, 2.1, 1 H), 4.29 (m, 1 H), 4.06 (t, J=5.9, 2 H), 4.04 (m, 1 H), 3.91 (dd, J=11.1, 7.2, 1 H), 2.64 (t, J=5.8, 2 H), 2.28 (s, 6 H); 13C NMR [(CD3)2SO]δ 160.3, 153.9, 153.0, 146.4, 142.8, 136.1, 131.6, 130.7, 127.4, 124.8, 124.7, 122.5, 116.0, 114.6, 113.1, 105.5, 103.1, 103.0, 66.1, 57.8, 54.9, 47.7, 45.5, 40.7.
