Sodium Hydroxide → (E)-4-methyl-2-styryl-1H-benzimidazole

HRID 50914

Reaction equation

HRID 50914 reaction equation
[NH2:1][C:2]1[C:7]([NH2:8])=[CH:6][CH:5]=[CH:4][C:3]=1[CH3:9].[C:10](O)(=O)/[CH:11]=[CH:12]/[C:13]1[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=1.[OH-].[Na+]>O>[CH3:9][C:3]1[C:2]2[N:1]=[C:10](/[CH:11]=[CH:12]/[C:13]3[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=3)[NH:8][C:7]=2[CH:6]=[CH:5][CH:4]=1

Participants

5

Reactant 3

HCID 14798Sodium HydroxideHCID 175932,3-DiaminotolueneHCID 444539Cinnamic Acid

Product 1

HCID 22736633(E)-4-methyl-2-styryl-1H-benzimidazoleYield 13%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Conditions

Temperature
180 °C

Procedure

A mixture of 2,3-diaminotoluene (2.44 g, 20 mmol), (E)-cinnamic acid (2.96 g, 20 mmol) and polyphosphoric acid (10 g) was heated to 180° C. for 90 min. The hot mixture was poured into water (100 ml), basified with 50% aqueous solution of sodium hydroxide and extracted with dichloromethane (3×100 ml). The combined extracts were washed with water (100 ml) and brine (100 ml), dried (magnesium sulfate) and concentrated to dryness. Purification by column chromatography (silica gel, 300 g; n-hexane/ethyl acetate (7/3)) yielded 0.61 g (13%) of the titled compound as red solids. 1H-NMR (CDCl3) δ: 9.53 (1H, br.s), 8.72-8.67 (1H, m), 7.95 (1H ddd, J=7.7, 7.7, 1.8 Hz), 7.60-7.49 (3H, m), 7.43-7.31 (3H, m), 7.23-7.14 (3H, m), 7.09-7.04 (1H, m), 2.63 (3H, br.s)

Workup

  1. extractionextracted with dichloromethane (3×100 ml)
  2. washThe combined extracts were washed with water (100 ml) and brine (100 ml)
  3. dry with materialdried (magnesium sulfate)
  4. concentrationconcentrated to dryness
  5. customPurification by column chromatography (silica gel, 300 g; n-hexane/ethyl acetate (7/3))

Sources & evidence

ORD record
ord-b0f1eea063734520b900fb83aca5fa76
Source dataset
uspto-grants-2004_03
Patent number
US06713482B2

Linked notes

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