2-Amino-5-nitrobenzimidazole

A suspension of 4-nitro-o-phenylenediamine (1.4 g, 9.1 mmol) in a solution of BrCN (0.97 g, 9.2 mmol) in water (30 mL) was heated under reflux for 7 h, cooled and neutralized with 25percent NH4OH to pH 10–11. The formed precipitate was then filtered, washed with water, air-dried and recrystallized from hot water. The title compound was obtained as an oranges yellow shiny crystals. Yeild=1.28 g (91.4percent); mp.245–247 °C. 1H NMR (400 MHz, DMSO‑d6, δ ppm): 8.10 (d, 1H, J=2.2 Hz, ArH), 7.90 (dd, 1H, J=8.70, 2.2 Hz, ArH), 7.20 (d, 1H, J=8.7 Hz, ArH), 6.90 (s, 2H, NH2). 13C NMR (400 MHz, DMSO‑d6, δppm): 158.91, 139.92, 136.67, 116.50, 111.16, 106.16. IR (KBr, cm−1):3514, 3457 (N-H stretching), 3092 (C-H aromatic stretching), 1658(C]N ring stretching), 1587, 1507 (skeletal bands), 1421 (asymmetricN]O stretching), 1471 (N-H scissoring), 1336 (symmetric N]Ostretching), 876 (N-H wagging). MS (+ESI-QTOF): m/z calculated forC7H6N4O2 [M+H]+ 179.14, found 179.1 (100percent).Step 1. General procedure: To a solution of o-aminophenol (400 mg, 3.67 mmol) and NCTS (998 mg, 3.67 mmol) in THF (6 mL), 1 M LiHMDS in hexane (3.67 mL, 3.67 mmol) was added and stirred at 5 °C to r.t. for 1h. Then the reaction mixture was poured in ice water and stirred for 15 min. Then extracted with EtOAc, the organic layer was separated. The organic layer was washed with brine solution.Then organic layer was dried over Na2SO4, filtered, and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography to obtained pure 2-aminobenzaxozole in 90percent yield (471 mg).4-Nitrobenzene-1, 2-diamine 1a (5.06g, 33mmol) was suspended in 90mL of a mixed solvent of acetonitrile and water (V/V=1:8), and bromoacetonitrile (3.55g, 33.5mmol) was added under stirring, the reaction solution was heated to reflux for 4 hours. To a stirred solution of 5-nitro-1 H-benzo[d]imidazol-2-amine (500 mg) in MeOH (15 ml_) was added 10percent Pd/C (149 mg) and the reaction mixture was stirred under a hydrogen atmosphere (balloon pressure) for 6 hr. The reaction mixture was filtered through Celite and the precipitate washed with MeOH (2 x 15 ml_). The combined filtrate was concentrated under reduced pressure to afford the titled compound (450 mg). LCMS m/z 149.0 )M+H).Taken 0.5-4g General procedure for the synthesis of AD1A mixture of

Molecular Weight:178.15
XLogP3:1.1
Hydrogen Bond Donor Count:2
Hydrogen Bond Acceptor Count:4
Exact Mass:178.04907545
Monoisotopic Mass:178.04907545
Topological Polar Surface Area:101
Heavy Atom Count:13
Complexity:217
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes