3,4-dihydropyrazino[1,2-a]benzimidazol-1(2H)-one → HCID 58044127、化合物

温度

95 °C

A 250-mL stainless steel pressure reactor was charged with 10% palladium on carbon (50% wet, 150 mg dry weight) and a solution of 152b (670 mg, 3.58 mmol) in acetic acid (25 mL). The reactor was evacuated, charged with hydrogen gas to a pressure of 350 psi and stirred at 95° C. for 16 h. After this time, the hydrogen was evacuated, and nitrogen was charged into the reactor. Celite 521 (1.00 g) was added, and the mixture was filtered through a pad of Celite 521. The filter cake was washed with ethanol (2×25 mL), and the combined filtrates were concentrated to dryness under reduced pressure. To the resulting residue was added water (10 mL), and followed by potassium carbonate to adjust pH to 9. The mixture was extracted with methylene chloride (4×20 mL), and the organic extracts were combined, dried over sodium sulfate, filtered and concentrated under reduced pressure to afford a 71% yield 152c (487 mg) as a white solid: mp>250° C.; 1H NMR (500 MHz, DMSO-d6) d 7.86 (s, 1H), 3.98 (t, 2H, J=6.5 Hz), 3.51 (m, 2H), 2.50 (m, 4H), 1.75 (m, 4H); MS (APCI+) m/z 192.6 (M+H).