Reaction Steps
Dissolve tin(II) chloride dihydrate (2.15 g, 9.5 mmol) in absolute ethanol (10 mL) and add it to N-[6-chloro-9-(2-nitro-benzyl)-2,3,4,9-tetrahydro-1H-carbazol-3-yl]-isobutyramide (Example 104) (810 mg, 1.9 mmol) in concentrated hydrochloric acid (10 mL). Heat the reaction at 60° C. for 1.5 h. Allow to cool and add 5N NaOH (27 mL) until pH=11-12. Extract the suspended solids into ethyl acetate (4×). Combine the organic portions and wash with water, brine, dry (MgSO4), and concentrate in vacuo to obtain a solid. Pass over a silica pad eluting with 25% ethyl acetate/dichloromethane to obtain 640 mg (85%). MS (ES): m/z 396, 398 (M+1), 394 (M−1); 1H NMR(DMSO-d6): δ 7.86 (d, 1H, J=7.5 Hz), 7.49 (d, 1H, J=1.8 Hz), 7.24 (d, 1H, J=8.8 Hz), 7.04 (dd, 1H, J=8.6, 2.0 Hz), 6.93 (dt, 1H, J=7.5, 1.3 Hz), 6.71 (dd, 1H, J=8.1, 1.1 Hz), 6.37 (dt, 1H, J=7.5, 1.3 Hz), 5.89 (d, 1H, J=7.0 Hz), 5.14 (m, 4H), 4.03 (m, 1H), 2.98 (dd, 1H, J=15.2, 5.1 Hz), 2.75-2.60 (m, 2H), 2.55 (m, 1H), 2.41 (m, 1H), 1.97 (m, 1H), 1.81 (m, 1H), 1.03 (d, 3H, J=4.0 Hz), 1.02 (d, 3H, J=4.4 Hz).
