O-Phenylenediamine → 2-(1-Methyl-3-pyrrolidinyl)-1H-benzimidazole

HRID 973418

Reaction equation

HRID 973418 reaction equation
[C:1]([CH:3]1[CH2:7][CH2:6][N:5]([CH3:8])[CH2:4]1)#[N:2].[NH2:9][C:10]1[CH:15]=[CH:14][CH:13]=[CH:12][C:11]=1N.[NH4+].[OH-]>Cl>[CH3:8][N:5]1[CH2:6][CH2:7][CH:3]([C:1]2[NH:9][C:10]3[CH:15]=[CH:14][CH:13]=[CH:12][C:11]=3[N:2]=2)[CH2:4]1

Participants

5

Reactant 3

HCID 7243O-PhenylenediamineHCID 14923Ammonium HydroxideHCID 108662851-Methylpyrrolidine-3-carbonitrile

Product 1

HCID 199898622-(1-Methyl-3-pyrrolidinyl)-1H-benzimidazole

Reagents, catalysts & solvents 1

HCID 313Hydrochloric AcidSolvent2×

Conditions

Temperature
110 °C

Procedure

To 240 g of concentrated hydrochloric acid was added 43.2 g (0.39 mol) of 3-cyano-1-methylpyrrolidine (the temperature rose to 90° C.). After the temperature began to fall the solution was heated to 110° C. for 4 h. The solution was cooled to 60° C. and 42 g (0.39 mol) of 1,2-diaminobenzene in 250 mL of 1N hydrochloric acid was added. The solution was heated to reflux for 20 h. The cooled solution was made basic with concentrated NH4OH and the resulting crystals were collected by filtration. The product was chromatographed on a 7.5×36 cm silica column eluting with 1 gallon of 10% NH4OH-90% ethanol. The eluent was collected in 500-mL portions. The first 6 fractions were discarded and fractions 7-14 were collected and concentrated. The residue was recrystallized from ethyl acetate. Yield: 18 g (23%). A 5-g sample was recrystallized three times from ethyl acetate. Yield: 1.6 g, mp 189°-193° C.

Workup

  1. customrose to 90° C.
  2. temperatureThe solution was cooled to 60° C.
  3. temperatureThe solution was heated
  4. temperatureto reflux for 20 h
  5. filtrationthe resulting crystals were collected by filtration
  6. customThe product was chromatographed on a 7.5×36 cm silica column
  7. washeluting with 1 gallon of 10% NH4OH-90% ethanol
  8. customThe eluent was collected in 500-mL portions
  9. customfractions 7-14 were collected
  10. concentrationconcentrated
  11. customThe residue was recrystallized from ethyl acetate
  12. customA 5-g sample was recrystallized three times from ethyl acetate

Sources & evidence

ORD record
ord-4825ff80ed504d4eac904674a4287a2c
Source dataset
uspto-grants-1991_11
Patent number
US05063228

Linked notes

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