To a solution of 2-(4-cyanobenzyl)-1,2,3,4-tetrahydroisoquinoline-7-carboxylic acid hydrochloride (50 mg, 0.17 mmol) in DMF (2 mL), HATU (78 mg, 0.21 mmol), 4-amino-1-(4-cyanobenzyl)piperidine dihydrochloride (52 mg, 0.18 mmol) and triethylamine (125 uL, 91 mg, 0.9 mmol) were added. The resulting reaction mixture was allowed to stir at room temperature overnight and poured into saturated sodium bicarbonate solution (30 mL) to give a white precipitate which was filtered and dried under vacuum. The resulting solid was triturated with ethyl ether to provide 2-(4-cyanobenzyl)-N-(1-(4-cyanobenzyl)piperidin-4-yl)-1,2,3,4-tetrahydroisoquinoline-7-carboxamide (compound 37) as a white crystalline solid (69 mg, 82%). 1H NMR (DMSO-d6): δ 8.08 (1H, d, J=7.7 Hz); 7.79 (4H, dd, J=8.5, 6.9 Hz); 7.60-7.54 (3H, m); 7.49 (3H, d, J=8.8 Hz); 7.16 (1H, d, J=8.3 Hz); 3.78-3.66 (3H, m); 3.55 (4H, br s); 2.86 (2H, t, J=5.2 Hz); 2.82-2.66 (4H, m); 2.04 (2H, t, J=11.3 Hz); 1.75 (2H, d, J=11.3 Hz); 1.55 (2H, q, J=11.8 Hz). MS (M+H)′=490.
