Benzimidazole → 3-Benzimidazolylchromone

HRID 1940008Notes

Reaction equation

HRID 1940008 reaction equation
[N:1]1[C:5]2[CH:6]=[CH:7][CH:8]=[CH:9][C:4]=2[NH:3][CH:2]=1.C1CCN2C(=NCCC2)CC1.O1[C:31]2[C:30](=[O:32])[C:29]3[C:24](=[CH:25][CH:26]=[CH:27][CH:28]=3)[O:23][C:22]1=2>C(#N)C.CN(C)C=O>[N:1]1[C:5]2[CH:6]=[CH:7][CH:8]=[CH:9][C:4]=2[NH:3][C:2]=1[C:31]1[C:30](=[O:32])[C:29]2[C:24](=[CH:25][CH:26]=[CH:27][CH:28]=2)[O:23][CH:22]=1

Participants

6

Reactant 3

HCID 5798BenzimidazoleHCID 811841,8-Diazabicyclo(5.4.0)undec-7-eneHCID 214655662,3-Epoxychromone

Product 1

HCID 128874993-BenzimidazolylchromoneYield 93%

Reagents, catalysts & solvents 2

HCID 6228DimethylformamideSolventHCID 6342AcetonitrileSolvent

Procedure

Benzimidazole (472 mg) and DBU (608 mg) were dissolved in acetonitrile (20 ml), and stirred at room temperature for 1 hour. To the resulting solution, a solution of 2,3-epoxychromone (162 mg) in dimethylformamide (5 ml) was added dropwise, and the whole was stirred for 5 minutes. After ice water was added, the reaction mixture was extracted with dichloromethane. The organic layer was dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The residue was fractionatedby silica gel column chromatography (ethyl acetate/hexane=1:3) to give the titled compound (122 mg; yield=93%). Melting point: 154° C. Mass spectrum (M+): 262. 1H-NMR(CDCl3, δ ppm): 8.21 (s, 1H, H2), 8.33 (dd, 1H, H5), 7.52 (t, 1H, H6), 7.80 (t, 1H, H7), 7.61 (d, 1H, H8), 8.35 (s, 1H, H2'), 7.33 (m, 3H, H4', 5', 6'), 7.86 (d, 1H, H7').

Workup

  1. stirringthe whole was stirred for 5 minutes
  2. extractionthe reaction mixture was extracted with dichloromethane
  3. dry with materialThe organic layer was dried over anhydrous sodium sulfate
  4. concentrationconcentrated under reduced pressure

Sources & evidence

ORD record
ord-8d77fe472c6549eebbaec7a45ee77197
Source dataset
uspto-grants-1997_12
Patent number
US05698575

Reaction notes

Loading…