Reaction Steps
A solution of 7-(3-thienyl)isoquinoline (0.15 g, 3 mmol) in dichloromethane was treated with an excess of HCl gas. The mixture was evaporated under reduced pressure to give a colourless solid. The solid was dissolved in ethanol, platinum oxide (100 mg) added, the reaction mixture hydrogenated at 50 psi on a Parr apparatus until uptake of hydrogen ceased. The catalyst was collected by filtration and the filtrate was hydrogenated again using fresh catalyst until the starting material had been consumed. The filtrate was evaporated under reduced pressure. The residue was dissolved in ethyl acetate (100 ml), washed with sodium carbonate solution (100 ml), dried over magnesium sulphate, filtered and evaporated under reduced pressure to give crude 7-(3-thienyl)-1,2,3,4-tetrahydroisoquinoline as an oil (0.41 g, 62%). A mixture of this oil (0.40 g, 1.85 mmol) and 3-dimethylaminomethyl-1H-pyrrolo[2,3-b]pyridine (0.325 g, 1.85 mmol) in toluene (3 ml) was heated at reflux under nitrogen for 6 h. The mixture was allowed to cool and the crystallised product collected. Recrystallisation from toluene afforded the title compound (0.17 g, 28%), m.p. 228°-230° C.; (Found: C, 72.82; H, 5.46; N, 12.05. C21H19N3S requires C, 73.01; H, 5.54; N, 12.16%); δH (DMSO-d6) 2.72 (2H, t, J 5.4 Hz, CH2), 2.80 (2H, t, J 5 Hz, CH2), 3.59 (2H, s, CH2), 3.82 (2H, s, CH2), 7.02 (1H, dd, J 7.7, 4.7 Hz, 5-H), 7.11 (1H, d, J 8.0 Hz, ArH), 7.35 (1H, s, ArH), 7.42-7.50 (3H, m, ArH), 7.57 (1H, dd, J 5.1, 3 Hz, ArH), 7.76 (1H, s, ArH), 8.04 (1H, dd, J 7.7, 1 Hz, 4-H), 8.20 (1H, dd, J 4.6, 1 Hz, 6-H), and 11.49 (1H, br s, NH); m/z (CI+, NH3) 345 (M+1)+.
