Reaction Steps
A mixture of 2-methoxy-7,8,9,10-tetrahydrophenanthridine (Compound 273, 48.17 g, 226 mmol) and sodium ethanethiolate (43.69 g, 520 mmol) in dry DMF was heated at 160° C. for 4 hours. After the reaction mixture was cooled to zero degrees C, acetic anhydride (63.9 ML, 678 mmol) was added and the reaction mixture was stirred for 30 minutes. The resulting thick white slurry was poured into 0.1 M pH 7.5 phosphate buffer (1.6 L) and extracted with ether (3×400 mL). The combined organic layers were washed with water (3×300 mL) and brine (300 mL), dried (MgSO4), filtered through a 3 cm×3 cm plug of silica, and evaporated in vacuo. The residue was purified by recrystallization from ethyl acetate-hexanes to give 45.70 g (86 percent) of Compound 274; white crystalline solid; mp 118°-119° C.; Rf =-- 0.39 (silica, 50 percent ethyl acetate in dichloromethane); IR (CHCl3) νmax 3018, 2938, 2861, 1758, 1507, 1369, 1193, 1174 cm-1 ; 1H NMR (300 MHz, CDCl3) δ 8.60 (s, 1 H, H6), 8.06 (d, J=9.0 Hz, 1 H, H4), 7.61 (d, J=2.5 Hz, 1 H, H1), 7.36 (dd, J=9.0, 2.5 Hz, 1 H, H3), 3.03 (t, J=6.0 Hz, 2 H, H7 or H10), 2.89 (t, J=6.0 Hz, 2 H, H7 or H10), 2.37 (s, 3 H, OCOCH3), 1.98-1.86 (m, 4 H, H8 and H9); 13C NMR (125 Mz, CDCl3) δ 169.5, 152.3, 148.4, 144.3, 140.9, 131.3, 130.1, 128.0, 122.9, 113.8, 27.0, 24.8, 22.2, 22.1, 21.1; MS (FAB+) m/e (rel intensity 242 (M+H, 100), 200 (25); HRMS for C15H16NO2 (M+H), calcd 242.1181, found 242.1181. Anal. Calcd for C15H15NO2 : C, 74.67; H, 6.27; N, 5.80. Found: C, 74.66; H, 6.37; N, 5.64.
