O-Phenylenediamine → 2-(Phenoxymethyl)-1H-benzimidazole

HRID 537307Notes

Reaction equation

HRID 537307 reaction equation
[C:1]1([NH2:8])[CH:6]=[CH:5][CH:4]=[CH:3][C:2]=1[NH2:7].[O:9]([CH2:16][C:17](O)=O)[C:10]1[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=1>Cl>[O:9]([CH2:16][C:17]1[NH:8][C:1]2[CH:6]=[CH:5][CH:4]=[CH:3][C:2]=2[N:7]=1)[C:10]1[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=1

Participants

4

Reactant 2

HCID 7243O-PhenylenediamineHCID 19188Phenoxyacetic Acid

Product 1

HCID 2100742-(Phenoxymethyl)-1H-benzimidazoleYield 90%

Reagents, catalysts & solvents 1

HCID 313Hydrochloric AcidSolvent

Conditions

Temperature
130 °C

Procedure

A 100 mL flask fitted with a stir-bar and condenser was charged with 1,2-phenylenediamine (9.94 g, 92.1 mmol), phenoxyacetic acid (14.0 g, 92.1 mmol), and 4M HCl (140 mL). The suspension was heated in a 130° C. bath forming a green solution. After 18 hr, the reaction had gone to completion as monitored by HPLC. The mixture was cooled in an ice bath forming a solid. The solid was filtered, pressed with rubber dam, and rinsed with H2O (2×15 mL). The residue was partitioned with EtOAc (300 mL) and saturated NaHCO3 (125 mL). The organic phase was washed with brine (100 mL), filtered through phase separation paper, and concentrated in vacuo to give 18.5 g of 61 as an off-white solid (90%). 1H NMR (300 MHz, CDCl3): δ 10.08 (bs, 1H), 7.82-7.40 (bm, 2H), 7.35-7.26 (m, 4H), 7.08-6.95 (m, 3H), 5.40 (s, 2H) ppm. HPLC analysis (15:10:75 H2O:A1:MeOH) showed a purity of greater than 99% with a retention time of 4.2 min.

Workup

  1. customA 100 mL flask fitted with a stir-bar and condenser
  2. customforming a green solution
  3. temperatureThe mixture was cooled in an ice bath
  4. customforming a solid
  5. filtrationThe solid was filtered
  6. washrinsed with H2O (2×15 mL)
  7. customThe residue was partitioned with EtOAc (300 mL) and saturated NaHCO3 (125 mL)
  8. washThe organic phase was washed with brine (100 mL)
  9. filtrationfiltered through phase separation paper
  10. concentrationconcentrated in vacuo

Sources & evidence

ORD record
ord-c9e6e1b1902a41d3a5323368f520d756
Source dataset
uspto-grants-2014_10
Patent number
US08859780B2

Reaction notes

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