Reaction Steps
4,5,6,7-Tetrahydro-thieno[3,2-c]pyridine (0.5 g, 3.59 mmol), benzotriazole (428 mg, 3.59 mmol), and 2-chlorobenzaldehyde (504 mg, 3.59 mmol) were dissolved in diethyl ether and stirred for 3 days in the presence of molecular sieves (4 Å) under an argon atmosphere at room temperature. After 3 days, the ether was filtered and washed with saturated sodium bicarbonate solution (20 mL). The ether was dried over sodium sulfate, filtered and concentrated. The remaining colorless foam was dissolved in heptane/diethyl ether (5 mL/1 mL) and stored in a freezer (−10° C.) overnight. After 20 hours at −10° C., the heptane was decanted and the remaining oil was dried under high vacuum at room temperature until a constant weight was achieved to provide 1-[(2-Chlorophenyl)-(6,7-dihydro-4H-thieno[3,2-c]pyridin-5-yl)-methyl]-1H-benzotriazole (Compound IVa, 0.84 g, 61.7% yield) as a colorless foam that appeared to be an 80:20 mixture of isomers by NMR. 1H NMR (300 MHz, CDCl3/TMS): δ=8.08 (d, 1H, J=8.1 Hz), 7.91-7.79 (m, 2H), 7.55 (d, 1H, J=8.4 Hz), 7.53-7.24 (m, 4H), 7.11 (s, 1H), 7.04 (d, 1H, J=5.1 Hz), 6.61 (d, 1H, J=5.1 Hz), 3.90 (d, 1H, J=14.4 Hz), 3.69 (d, 14.4 Hz), 3.21-2.95 (m, 2H), 2.88 (m, 2H). (major isomer). 13C NMR (75 MHz, CDCl3/TMS): δ=145.48, 133.78, 133.45, 132.94, 132.65, 130.10, 129.40, 127.50, 126.98, 126.56, 124.97, 124.00, 122.79, 119.80, 110.39, 84.85, 49.59, 47.28, 25.50. (major isomer). MS (HR, DIP-CI): Calculated for (MH+): 379.0779. found 379.0752.
