Reaktion #1285027

Reaktionsgleichung

NH4OH

Methyl [5-(4-fluorobenzoyl)-1H-benzimidazol-2-yl]carbamate

methoxylamine hydrochloride

methanol

→

title product

Methyl [5-[(4-Fluorophenyl) (Methoxyimino)Methyl]-1H-Benzimidazol-2-yl]Carbamate

Lösungsmittel

H2O

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturAfter heating
2. 2
   Temperaturunder reflux for 48 hrs a clear solution
3. 3
   Sonstigewas obtained
4. 4
   FiltrationAfter 72 hrs this mixture was filtered hot through Celite
5. 5
   SonstigeRemoval of solvent under reduced pressure
6. 6
   Sonstigegave a solid residue
7. 7
   Sonstigewas isolated by filtration
8. 8
   Waschenwashed repeatedly with H2O
9. 9
   Sonstigedried at 50° C. under reduced pressure

Vorschrift

Methyl [5-(4-fluorobenzoyl)-1H-benzimidazol-2-yl]carbamate (Janssen Pharmaceutica, U.S. Pat. No. 3,657,267, Apr. 18, 1972) (31.61 g, 0.11 mole) and methoxylamine hydrochloride (0.35 mole) were added to abs. methanol. After heating under reflux for 48 hrs a clear solution was obtained. After 72 hrs this mixture was filtered hot through Celite then allowed to cool to room temperature. Removal of solvent under reduced pressure gave a solid residue. This material was suspended in H2O and adjusted to pH 12 with conc NH4OH. After stirring for 10 min the precipitate was isolated by filtration, washed repeatedly with H2O, then dried at 50° C. under reduced pressure to give the title product as a white solid. Yield: 33.08 g (96%). Mp: 290°-295° C., TLC: Rf=0.66,0.77 (CHCl3 --MeOH,10:1,SiO2) syn and anti isomers. IR (KBr): 3350, 2939, 1735 cm-1. 1H NMR (DMSO-d6): δ 3.73-3.75 (D, 3H, CH3); 3.85-3.87 (d, 3H, CH3); 6.95-7.46 (m, 7H, Ar); 11.74 (brd, s, 2 H, NH).

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