Hydrochloric Acid → 1-Benzyl-4-(4-methoxyphenyl)-1,2,3,6-tetrahydropyridine

Participants

Reaction Conditions

Reaction Steps

6 M HCl (100 mL, aqueous) was added to a solution of 1-benzyl-4-(4-methoxyphenyl)piperidin-4-ol (12.31 g, 41.36 mmol) in dioxane (50 mL), and the reaction was heated to strong reflux (110° C.). After 2 hours, the reaction was not complete. The heat was turned off and the reaction was left to stir at ambient temperature for 2 days. The reaction had progressed but was not complete so it was heated to 110° C. After 1 hour, the reaction was cooled and the volume was reduced by approximately one third. The solution was then cooled in an ice bath and neutralized with NaOH pellets. The thick suspension was filtered. The precipitate was rinsed with water and then dried under vacuum at 70° C. to afford 6.2 g (47%) of the titled compound. 1H NMR (400 MHz, CDCl3) δ ppm 2.74-2.62 (m, 1H), 3.30-3.06 (m, 2H), 3.50 (d, J=18.5, 1H), 3.67-3.56 (m, 1H), 3.82 (s, 3H), 4.03-3.90 (m, 1H), 4.21 (dd, J=5.7, 13.0, 1H), 4.34 (dd, J=5.1, 13.0, 1H), 5.88 (s, 1H), 6.88 (d, J=8.7, 2H), 7.32 (d, J=8.7, 2H), 7.51-7.43 (m, 3H), 7.71 (dd, J=2.7, 6.3, 2H), 12.85 (s, 1H); MS (ESI) m/z 280 (M+H)+; MS (DCI) m/z 280 (M+H)+.

Provenance & Evidence