Acetic Acid → 1H-Benzimidazole, 2-(2,4-dimethoxyphenyl)-

HRID 10691

Reaktionsgleichung

Reaktionsgleichung von HRID 10691
[C:1]1([NH2:8])[C:2]([NH2:7])=[CH:3][CH:4]=[CH:5][CH:6]=1.[CH3:9][O:10][C:11]1[CH:18]=[C:17]([O:19][CH3:20])[CH:16]=[CH:15][C:12]=1[CH:13]=O.C(O)(=O)C>C(O)C>[CH3:9][O:10][C:11]1[CH:18]=[C:17]([O:19][CH3:20])[CH:16]=[CH:15][C:12]=1[C:13]1[NH:8][C:1]2[CH:6]=[CH:5][CH:4]=[CH:3][C:2]=2[N:7]=1

Komponenten

5

Edukt 3

HCID 176Acetic AcidHCID 7243O-PhenylenediamineHCID 691752,4-Dimethoxybenzaldehyde

Produkt 1

HCID 161159151H-Benzimidazole, 2-(2,4-dimethoxyphenyl)-Ausbeute 12,4 %

Reagenzien, Katalysatoren, Lösungsmittel 1

HCID 702EthanolLösungsmittel

Versuchsvorschrift

Ex-70A: A solution of benzene-1,2-diamine (2.60 g, 24.1 mmol) and 2,4-dimethoxy-benzaldehyde (4.0 g, 24.1 mmol) in ethanol (60 mL) containing catalytic amount of acetic acid was refluxed overnight. Solvent was then evaporated under reduced pressure. The residue oil was triturated in ethyl acetate to obtain 2-(2,4-dimethoxy-phenyl)-1H-benzoimidazole (0.76 g, 12%). The crude product was used without further purification. To a solution of 2-(2,4-dimethoxy-phenyl)-1H-benzoimidazole obtained above (0.76 g, 2.99 mmol) in dichloromethane (20 mL) was added dichloromethyl methyl ether (0.41 mL, 4.48 mmol) followed by addition of titanium tetrachloride (1.0M in dichloromethane, 9.0 mL, 9.0 mmol) at 0° C. The reaction mixture was allowed to stir overnight at ambient temperature and then poured into ice. A solution of sodium hydroxide (5M) was added dropwise until the pH of the solution was about 12. The basic solution was extracted with dichloromethane. The combined solution of dichloromethane was subsequently washed with brine, dried over sodium carbonate and concentrated. The product, 5-(1H-benzoimidazol-2-yl)-2,4-dimethoxy-benzaldehyde (0.40 g, 47%), was obtain and used without further purification. 1H NMR (CDCl3) δ 10.32 (s, 1H), 10.27 (bs, 1H), 9.03 (s, 1H), 7.83 (d, J=9 Hz, 1H), 7.48–7.45 (m, 1H), 7.31–7.22 (m, 1H), 6.58 (s, 1H), 4.18 (s, 3H), 4.01 (s, 3H). MS m/z=282 (M+, 100%).

Aufarbeitung

  1. temperaturewas refluxed overnight
  2. customSolvent was then evaporated under reduced pressure
  3. customThe residue oil was triturated in ethyl acetate

Quellen und Nachweise

ORD-Eintrag
ord-0d8916d749ee4c9582da95c822c09a05
Quelldatensatz
uspto-grants-2006_08
Patentnummer
US07094801B2

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