tert-Butanol → 1,4,6-Trimethyl-2,3-dihydro-1H-pyrrolo[2,3-b]pyridine

Participants

Reaction Conditions

Reaction Steps

To a solution containing 1.20 g (12.1 mmol) of 4-amino-3-penten-2-one in 8 mL of toluene was added 3.00 g (20.7 mmol) of 2,2-Dimethoxy-1-methylpyrrolidine. The reaction mixture was heated at reflux and stirred for 2 h, cooled to 90° C., and then treated with 2.38 g (24.8 mmol) of t-BuONa and 2 mL of t-BuOH. The reaction mixture was stirred at 90° C. for another 16 h. The cooled reaction mixture was quenched by the addition of 10 mL of sat aq. NH4Cl. The mixture was extracted with three 30-mL portions of EtOAc. The combined organic layer was washed with brine, dried over anhydrous MgSO4, filtered, and concentrated under diminished pressure. The residue was purified via flash chromatography on a silica gel column (42×2.5 cm). Step gradient elution with 1:4→1:1 ethyl acetate-hexanes as eluent gave 1,4,6-trimethyl-2,3-dihydro-1H-pyrrolo[2,3-b]pyridine as a brown oil: yield 0.62 g (32%); silica gel TLC Rf 0.15 (1:4 ethyl acetate-hexanes); 1H NMR (CDCl3) 1.91 (s, 3H), 2.20 (s, 3H), 2.65 (t, 2H, J=8.4 Hz), 2.76 (s, 3H), 3.23 (t, 2H, J=8.4 Hz), 5.98 (s, 1H).

Provenance & Evidence