Reaction Steps
To an EtOAc solution (0.9 mL) of 14c (271 mg, 1.0 mmol) was added 2 M ethereal HCl (3.6 mL), and then the solvent was removed in vacuo and the residual 14c.HCl salt was dissolved in MeOH (5.4 mL) and PtO2 (14 mg) was added. The mixture was hydrogenated under 1 atm of H2 (1 h). The catalyst was filtered, and the solvent was removed in vacuo. The residue was dissolved in aqueous 1 N NaOH (3.5 mL) and extracted with EtOAc (3×15 mL). The organic extracts were combined, dried (Na2SO4), concentrated, and then dissolved in ethyl acrylate (1.1 mL, 10 mmol) and stirred at 80° C. (20 h). The reaction was concentrated to dryness and the residue was separated by PTLC (EtOAc/hexanes=2/3) to give 15c (48 mg, 13%) and 17 (32 mg, 12%), respectively. Compound 15c: clear oil; Rf 0.57 (EtOAc/hexanes=1/1); IR (neat) 2978, 2935, 2862, 1731, 1454, 1372, 1181 cm−1; 1H NMR (CDCl3) δ 1.24 (t, J=7.2 Hz, 3H), 1.25 (t, J=7.2 Hz, 3H), 1.64-1.77 (m, 4H), 2.43-2.54 (m, 3H), 2.66 (dd, J=3.9, 12.2 Hz, 1H), 2.82-2.97 (m, 4H), 3.45 (dd, J=5.9, 9.6 Hz, 1H), 3.66 (dd, J=5.4, 9.6 Hz, 1H), 4.12 (q, J=7.2 Hz, 4H), 4.47 (1/2 AB, J=12.2 Hz, 1H), 4.52 (1/2 AB, J=12.2 Hz, 1H), 7.27-7.34 (m, 5H), 13C NMR (CDCl3) 14.1, 14.2, 23.3, 25.9, 33.1, 40.6, 50.1, 50.3, 57.6, 60.1, 60.2, 69.3, 73.2, 127.4, 127.5 (2C), 128.3 (2C), 138.3, 172.7, 174.1 ppm; MS (+CI) 378 [M+1]+; Mr (+CI) 378.228 63 [M+1]+ (calcd for C21H32NO5 378.228 05). Compound 17 (King et al., “Substituted Benzamides with Conformationally Restricted Side Chains. 5. Azabicyclo[xyz] Derivatives as 5-HT4 Receptor Agonists and Gastric Motility Stimulants”, J. Med. Chem. 1993, 36, 683-689) (cis- and trans-mixture): yellow oil; Rf 0.44 (EtOAc/hexanes=1/1); IR (neat) 2974, 2924, 2814, 1735, 1455, 1377 cm−1; 1H NMR (CDCl3) δ 1.00 (d, J=6.6 Hz, 1.4H), 1.10 (d, J=6.6 Hz, 1.6H), 1.23-1.28 (m, 6H), 1.40-2.01 (m, 4H), 2.18-2.31 (m, 1H), 2.42-2.59 (m, 4H), 2.67-2.88 (m, 2H), 3.03-3.10 (m, 1H), 4.08-4.17 (m, 4H), 13C NMR (CDCl3) 13.7 (2C), 14.2 (2C), 19.9 (2C), 23.1 (2C), 27.4 (2C), 32.7, 33.8, 41.2, 42.2, 48.8, 49.6, 49.8, 53.3, 54.1, 55.1, 60.2 (2C), 60.3 (2C), 172.8 (2C), 174.1 (2C) ppm; MS (+CI) 272 [M+1]+; Mr (+CI) 272.186 63 [M+1]+ (calcd for C14H26NO4 272.186 18).
