Benzyl Bromide → 1-Benzyl-2,5,6-trichlorobenzimidazole

HRID 1900129Notes

Reaction equation

HRID 1900129 reaction equation
[Cl:1][C:2]1[NH:3][C:4]2[CH:10]=[C:9]([Cl:11])[C:8]([Cl:12])=[CH:7][C:5]=2[N:6]=1.C([O-])([O-])=O.[K+].[K+].[CH2:19](Br)[C:20]1[CH:25]=[CH:24][CH:23]=[CH:22][CH:21]=1>CC#N>[CH2:19]([N:6]1[C:5]2[CH:7]=[C:8]([Cl:12])[C:9]([Cl:11])=[CH:10][C:4]=2[N:3]=[C:2]1[Cl:1])[C:20]1[CH:25]=[CH:24][CH:23]=[CH:22][CH:21]=1

Participants

5

Reactant 3

HCID 7498Benzyl BromideHCID 11430Potassium CarbonateHCID 2860092,5,6-Trichloro-1H-benzimidazole

Product 1

HCID 108288581-Benzyl-2,5,6-trichlorobenzimidazoleYield 96.3%

Reagents, catalysts & solvents 1

HCID 6342AcetonitrileSolvent

Procedure

2,5,6-Trichlorobenzimidazole (5, 50 mg, 0.0002 moles) was dissolved in 15 ml of CH3CN, and K2CO3 (33 mg, 0.0002 moles) was added. The mixture was stirred at room temperature for one hour, at which time benzyl bromide (0.024 ml, 0.0002 moles) was added. The mixture was then stirred for two days. TLC analysis showed the formation of a new compound with a higher Rf than starting material. The mixture was then concentrated and a liquid-liquid extraction was done using CHCl3, and H2O. The CHCl3 layer was kept, dried with MgSO4, filtered, and then concentrated. Column chromatography was then performed using 2% MeOH/CHCl3 to elute the compounds. The fractions were collected and those containing the compound were concentrated. The compound was recrystallized from MeOH, giving 60 mg of 1-benzyl-2,5,6-trichlorobenzimidazole (181) (96.2%). 1H NMR (CDCl3): d 3.49 ppm (s, 3H), 7.13 (m, 2H), 7.32 (m, 4H), 7.78 (c, 1H), 13C NMR (CDCl3): d 43.20 ppm, 106.25, 115.78, 121.62, 122.24, 122.66, 123.50, 124.15, 129.05, 129.16, 135.97, 137.68. GC-MS: m/e 310, 273, 239, 221, 197, 170, 158, 138, 120, 100, 91, 77, 65, 51, 39. m.p: 175°-176° C. Elemental AnalysiS: (C14H9Cl3N2): Calculated: C, 53.85; H, 2.88; N, 8.97. Found: C, 53.92; H, 2.85; N, 8.89. UV Imax nm (e×104): (pH 7) 263 (0.080), 290 (0.102), 299 (0.154); (pH 1) 224 (0.412), 258 (0.155), 299 (0.166).

Workup

  1. additionwas added
  2. concentrationThe mixture was then concentrated
  3. extractiona liquid-liquid extraction
  4. dry with materialdried with MgSO4
  5. filtrationfiltered
  6. concentrationconcentrated
  7. washto elute the compounds
  8. customThe fractions were collected
  9. concentrationthose containing the compound were concentrated
  10. customThe compound was recrystallized from MeOH

Sources & evidence

ORD record
ord-af72f330386a444e98602f12cd06defa
Source dataset
uspto-grants-1996_11
Patent number
US05574058

Reaction notes

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