1,2-Phenylenediamine dihydrochloride → 2-cyclopropyl-1H-1,3-benzodiazole

HRID 2085337

Reaction equation

HRID 2085337 reaction equation
[CH2:1]1[CH2:3][CH:2]1[C:4](O)=O.Cl.Cl.[C:9]1([NH2:16])[CH:14]=[CH:13][CH:12]=[CH:11][C:10]=1[NH2:15].[OH-].[Na+]>O>[CH:2]1([C:4]2[NH:15][C:10]3[CH:11]=[CH:12][CH:13]=[CH:14][C:9]=3[N:16]=2)[CH2:3][CH2:1]1

Participants

5

Reactant 3

HCID 119901,2-Phenylenediamine dihydrochlorideHCID 14798Sodium HydroxideHCID 15655Cyclopropanecarboxylic acid

Product 1

HCID 10844192-cyclopropyl-1H-1,3-benzodiazoleYield 13%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Conditions

Temperature
160 °C

Procedure

2-cyclopropanecarboxylic acid (4 g, 52 mmol) was treated with phenylenediamine bis-hydrochloride (1 eq) and polyphosphosphoric acid (52 mL) and heated to 160° C. for 6 h. The reaction was cooled to 0° C. and diluted with water, then basified with NaOH (50% aqueous) until pH>10. The solution was extracted with ethyl acetate, dried (MgSO4), filtered and concentrated, purified by flash chromatography (100% ethyl acetate) giving 2-cyclopropylbenzimidazole (1.1 g, 13%). MS found: (M+H)+=159.

Workup

  1. temperatureThe reaction was cooled to 0° C.
  2. extractionThe solution was extracted with ethyl acetate
  3. dry with materialdried (MgSO4)
  4. filtrationfiltered
  5. concentrationconcentrated
  6. custompurified by flash chromatography (100% ethyl acetate)

Sources & evidence

ORD record
ord-6ebfa19a6cfc4642af8e40307979b7b3
Source dataset
uspto-grants-2004_04
Patent number
US06720329B2

Linked notes

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