Acetic Acid → 3-amino-1H-1,5-benzodiazepine-2,4(3H,5H)-dione

Participants

Reaction Conditions

Reaction Steps

Wet 10% Pd/C (37.5 g) with glacial acetic acid (HOAc, 3.75 L). Add 1,5-dihydro-benzo[b][1,4]diazepine-2,3,4-trione 3-(O-methyl-oxime) (150 g, 0.684 mol), and subject the resulting mixture to catalytic hydrogenation under 50 psi H2 at ambient temperature for ˜18 hours until complete by HPLC. Remove the catalyst by filtration over glass fiber paper/Hyflo and rinse with HOAc (2 L). Concentrate the filtrate in vacuo to obtain the crude product as an amber waxy solid. Treat the solid with ethyl acetate (EtOAc, 3 L) and heat to 70° C. with stirring for 1 hour. Allow the slurry to cool to ambient temperature, then force cool to 0° C. Isolate the product by filtration and dry to afford 109.9 g (84%) of the title compound: 1H NMR (300 MHz, DMSO-d6) δ 10.48 (bs, 2H), 7.18 (m, 4H), 3.75 (s, 1H), ˜3.5 (bs, 2H); 13C NMR (75 MHz, DMSO-d6) δ 167.9, 164.5, 129.2, 125.1, 122.2, 55.8, 55.7; IR (KBr) 3375, 3306, 3282, 3047, 2750, 1697, 1670, 1559, 1500, 1433, 1411, 1337, 1307, 1258, 1183 cm−1; V (EtOH) λmax 217 nm (ε 33772), 285 nm (ε 3210); HRMS (ES+) exact mass calc'd for C9H9N3O2 192.0773, Found 192.0768.

Provenance & Evidence