Benzyl Bromide → 1-Benzyl-4-(1,3-diethyl-5-methyl-pyrazol-4-yl)-1,2,3,6-tetrahydropyridine

Participants

Reaction Conditions

Reaction Steps

A solution of 7.55 g (35.0 mmol) of 1,3-diethyl-4-(4-pyridyl)-5-methylpyrazole (from Step E) and 4.20 mL (35.0 mmol) of benzyl bromide in 50 mL of MeOH was heated at reflux for 30 min. The mixture was cooled to 0° C. and treated with 2.65 g (70.0 mmol) of sodium borohydride in portions so as to maintain the internal at ˜0° C. The resulting mixture was stirred cold for 30 min, then concentrated. The residue was partitioned between 300 mL of CH2Cl2 and 150 mL of 1.0 N NaOH and the layers were separated. The organic layer was dried over MgSO4. The organic layer was extracted with 300 mL of ether; the extract was dried over MgSO4. The organic layers were combined and concentrated. Chromatography on a Biotage 75L using 9:1 v/v heptane/acetone as the eluant afforded the title compound. 1H-NMR (400 MHz) δ 1.19 (t, J=7.6, 3H), 1.37 (t, J=7.6, 3H), 2.17 (s, 3H), 2.31-2.35 (m, 2H), 2.58 (q, J=7.6, 2H), 2.66 (t, J=5.6, 2H), 3.13 (app q, J=2.8, 2H), 3.65 (s, 2H), 4.01 (q, J=7.6, 2H), 5.46-5.48 (m, 1H), 7.26-7.39 (5H).

Provenance & Evidence