Reaction Steps
Trifluoroacetic acid (5 ml) was added to a solution of 1-tert-butoxycarbonyl)-4-(1-methyl-5-indolyl)piperazine (0.2102 g, 0.666 mmol) in dichloromethane (5 ml) and the mixture stirred for 30 minutes at room temperature. The mixture was concentrated in vacuo and saturated aqueous potassium carbonate (20 ml) was added to the residue. The mixture was extracted with dichloromethane (2×20 ml), the extracts washed with brine (20 ml), combined and dried (MgSO4). The extracts were concentrated and the residual yellow solid redissolved in toluene (5 ml). 3-Dimethylaminomethyl-1H-pyrrolo[2,3-b]pyridine (0.1136 g, 0.648 mmol) was added and the mixture heated at reflux under nitrogen for 5 hours. The mixture was allowed to cool and the solid present collected. Purification by flash chromatography, eluting with 120:8:1 then 90:8:1 dichloromethane/methanol/ammonia, gave the title compound (0.1433 g, 64%) as a yellow solid. Recrystallisation from methanol afforded pale yellow needles, m.p. 222°-223° C.; (Found: C, 72.81; H, 6.81; N, 20.17. C21H23N5 requires C, 73.02; H, 6.71; N, 20.27%); δH (DMSO-d6) 2.57 (4H, m, 2×piperazinyl CH2), 3.03 (4H, m, 2×piperazinyl CH2), 3.69 (2H, s, CH2N), 3.71 (3H, s, N--CH3), 6.25 (1H, d, J 2.9 Hz, 3'-H), 6.89 (1H, dd, J 8.9, 2.1 Hz, 6'-H), 6.98 (1H, d, J 2.0 Hz, 2-H or 4'-H), 6.98 (1H, d, J 2.9 Hz, 2'-H), 7.26 (1H, d, J 8.9 Hz, 7'-H), 7.38 (1H, d, J 2.1 Hz, 4'-H) or 2-H), 8.07 (1H, dd, J 7.8, 1.4 Hz, 4-H), 8.20 (1H, dd, J 4.6, 1.4 Hz, 6-H), and 11.46 (1H, br s, NH); m/z (CI+, NH2) 346 (M+1)+.
