Hydrochloric Acid → HCID 131734542, compound

Participants

Reaction Conditions

Reaction Steps

Into a 100 mL eggplant-shaped flask were added benzyl 3-(2-methoxyacetyl)-2-oxopyrrolidine-1-carboxylate potassium salt (4.95 g) [mw. 329.39, 15.0 mmol], 1 mol/L hydrochloric acid (25 mL) [25 mmol] and toluene (50 mL), and the mixture was stirred for 20 min. After partitioning, the organic layer was dried over magnesium sulfate, filtered and concentrated under reduced pressure. To the concentrate were added toluene (19 mL), cyclohexane (57 mL), p-toluenesulfonic acid monohydrate (29.0 mg) [mw. 190.22, 0.15 mmol] and parabromoaniline (2.58 g) [mw. 172.02, 15.0 mmol]. Dean-Stark trap was set, and the mixture was subjected to dehydration reflux for 2 hr. After cooling to 25° C., 5 w/w % aqueous sodium bicarbonate solution (10 mL) was added to allow for partitioning. The organic layer was washed with water (10 mL), dried over magnesium sulfate, filtered and concentrated under reduced pressure. To the concentrate was added methanol (19 mL), and the mixture was dissolved. Activated carbon (0.5 g) was added, and the mixture was stirred. The activated carbon was filtered off, the mother liquor was concentrated under reduced pressure, and to the concentrate were added ethyl acetate (2 mL) and diisopropyl ether (20 mL). The mixture was left standing in a freezer at −16° C. overnight, and crystallization was confirmed. The mixture was aged at room temperature for 1 hr. After filtration under reduced pressure, the crystals were washed with ethyl acetate/diisopropyl ether (1/10), and dried under reduced pressure at 50° C. Yellow crystals, 4.12 g, yield 61.6%, 1H-NMR (500 MHz, CDCl3, TMS) δ 2.78 (t, J=7.7 Hz, 2H), 3.35 (s, 3H), 3.76-3.89 (m, 2H), 4.00 (s, 2H), 5.30 (s, 2H), 6.99 (d, J=8.8 Hz, 5H), 7.28-7.52 (m, 7H), 10.49 (s, 1H). 13C-NMR (125 MHz, CDCl3, CDCl3) δ 20.95, 43.60, 58.55, 67.74, 67.97, 99.87, 117.24, 124.08, 128.13, 128.58, 132.24, 135.78, 138.56, 149.72, 152.24, 169.92.

Provenance & Evidence