Benzenepropanoic acid → 2-(2-phenylethyl)-1H-benzimidazole

HRID 537316Notes

Reaction equation

HRID 537316 reaction equation
[C:1]1([NH2:8])[CH:6]=[CH:5][CH:4]=[CH:3][C:2]=1[NH2:7].[C:9](O)(=O)[CH2:10][CH2:11][C:12]1[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=1>Cl>[C:12]1([CH2:11][CH2:10][C:9]2[NH:7][C:2]3[CH:3]=[CH:4][CH:5]=[CH:6][C:1]=3[N:8]=2)[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=1

Participants

4

Reactant 2

HCID 107Benzenepropanoic acidHCID 7243O-Phenylenediamine

Product 1

HCID 2910532-(2-phenylethyl)-1H-benzimidazoleYield 83%

Reagents, catalysts & solvents 1

HCID 313Hydrochloric AcidSolvent

Procedure

A 100 mL flask fitted with a stir-bar and condenser was charged with 1,2-phenylenediamine (2.88 g, 26.6 mmol), hydrocinnamic acid (4.00 g, 26.6 mmol), and 4M HCl (40 mL). The resultant suspension was heated in a 130° C. bath 48 hr. The mixture was cooled, and the precipitate was filtered. The solid was suspended in H2O (70 mL), and the suspension was brought to pH 11 with 50% aqueous NaOH and stirred overnight. The pH was readjusted from 3 to 11 with 50% NaOH. The solid was filtered, pressed with rubber dam, and rinsed with H2O (2×10 mL). The material was dried to give 4.9 g of 67 as a white solid (83%). 1H NMR (60 MHz, CDCl3): δ 12.3 (s, 1H), 7.6-7.4 (m, 2H), 7.4-6.8 (m, 7H), 3.2 (s, 4H) ppm. HPLC analysis (15:10:75 H2O:A1:MeOH) showed a purity of greater than 99% with a retention time of 3.2 min.

Workup

  1. customA 100 mL flask fitted with a stir-bar and condenser
  2. temperatureThe mixture was cooled
  3. filtrationthe precipitate was filtered
  4. filtrationThe solid was filtered
  5. washrinsed with H2O (2×10 mL)
  6. customThe material was dried

Sources & evidence

ORD record
ord-e585d511ccc14705b326c6fbba2352a6
Source dataset
uspto-grants-2014_10
Patent number
US08859780B2

Reaction notes

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