A solution of 3-(3-Pyridyl)-1-propyl pyrrolidine-2-carboxylate (200 mg; 0.9 mmol) and α-toluenesulfonyl chloride (160 mg; 0.9 mmol) in methylene chloride (20 mL) was treated with triethylamine (90 mg; 0.9 mmol) and stirred for 2 hours at room temperature. The reaction mixture was filtered to remove solids and applied directly to a silica gel column, eluting with 50% ethyl acetate in hexane, to obtain 150 mg (43%) of Compound 4 (Table I) as a clear oil. 1H NMR (300 MHz, CDCl3): δ1.81-1.85 (m, 2H); 1.95-2.02 (m, 3H); 2.10-2.25 (m, 1H); 2.69-2.74 (t, 2H); 2.85-2.97 (m, 1H); 3.24-3.27 (m, 1H); 4.16-4.20 (m, 2H); 4.29 (d, 1H); 4.34 (m, 1H); 4.45 (d, 1H); 7.20-7.25 (m, 1H); 7.35 (m, 3H); 7.49-7.52 (m, 3H); 8.46 (s, 2H). Analysis calculated for C20H24N2O3S: C, 61.83; H, 6.23; N, 7.21. Found: C, 61.59; H, 6.24; N, 7.17.
