6-((trans)-4-tert-butylcyclohexyloxy)-2-naphthaldehyde (300 mg, 0.96 mmol, 1 equiv) and 3-amino-N-(methylsulfonyl)propanamide (239 mg, 1.19 mmol, 1.5 equiv) were dissolved in anhydrous EtOH. The mixture was stirred at 80° C. for 1 h. Then NaBH3CN (110 mg, 1.74 mmol, 2 equiv) was added to the mixture and stirred at 80° C. for 16 h. The organic layer was concentrated and purified by prep-TLC to give 3-((6-((trans)-4-tert-butylcyclohexyloxy)naphthalen-2-yl)methylamino)-N-(methylsulfonyl)propanamide as a white solid (62 mg, 14%). (mobile phase: CH3OH/DCM=1:10). ESI-MS (M+1)+: 461.2, HPLC: 96.38%. 1H NMR (400 MHz, DMSO-d6) δ: 7.93 (s, 1H), 7.85˜7.77 (m, 2H), 7.59˜7.49 (m, 1H), 7.43˜7.35 (m, 1H), 7.20˜7.11 (m, 1H), 4.45˜4.33 (m, 1H), 4.20 (s, 2H), 2.98 (t, 2H), 2.77 (s, 3H), 2.35 (t, 2H), 2.26˜2.14 (m, 2H), 1.86˜1.75 (m, 2H), 1.41˜1.30 (m, 2H), 1.27˜1.14 (m, 2H), 1.13˜1.02 (m, 1H), 0.89 (s, 9H).
