Hydrochloric Acid → 2-[(5-Chloro-2-methoxyphenyl)AZO]-1H-imidazole

HRID 1446978Notes

Reaction equation

HRID 1446978 reaction equation
[Cl:1][C:2]1[CH:7]=[CH:6][C:5]([O:8][CH3:9])=[C:4]([NH2:10])[CH:3]=1.Cl.[N+:12]([O-])([O-])=O.[Na+].[NH:17]1[CH:21]=[CH:20][N:19]=[CH:18]1.[OH-].[Na+].C([O-])(=O)C.[Na+]>O>[CH3:9][O:8][C:5]1[CH:6]=[CH:7][C:2]([Cl:1])=[CH:3][C:4]=1[N:10]=[N:12][C:18]1[NH:17][CH:21]=[CH:20][N:19]=1

Participants

8

Reactant 6

HCID 313Hydrochloric AcidHCID 795Imidazole2×HCID 14798Sodium HydroxideHCID 24268Sodium NitrateHCID 667635-Chloro-2-methoxyanilineHCID 517045Sodium Acetate

Product 1

HCID 1324542-[(5-Chloro-2-methoxyphenyl)AZO]-1H-imidazole

Reagents, catalysts & solvents 1

HCID 962WaterSolvent3×

Procedure

An example of preparing the azo compound may be illustrated as follows: To 50 parts by weight of water are added 5.1 parts by weight of 4-chloro-2-aminoanisole and 7.6 parts by weight of 35% hydrochloric acid, and a mixture of 2.2 parts by weight of sodium nitrate and 15 parts by weight of water is added thereto at 0°-5° C. The resulting mixture is stirred for 1 hour for the completion of diazotation. The first reaction mixture is then added at 0°-5° C. to a solution of 20.4 parts by weight of imidazole, 1.7 parts by weight of sodium hydroxide and 2.5 parts by weight of sodium acetate in 150 parts by weight of water. Stirring of the mixture for 1 hour can allow the diazonium salt to effect the coupling with imidazole, thereby precipitating a yellow-orange product. The product is then filtered, washed with water and then dried at 60° C. to provide 7.6 parts by weight of the crude azo compound. This crude azo compound (7 parts by weight) is recrystallized from n-propylalcohol to provide 7.6 parts by weight of pure 2-[(2-methoxy-5-chlorophenyl)azo]-1H-imidazole, having a melting point of 205° C. (decomposed), when measured in accordance with the designation of the Japanese Pharmacopoeia. It has a maximum ultraviolet absorption peak (λmax) at 384 mμ and its elementary analysis indicates as follows:

Workup

  1. additionis added
  2. customat 0°-5° C
  3. stirringStirring of the mixture for 1 hour
  4. customprecipitating a yellow-orange product
  5. filtrationThe product is then filtered
  6. washwashed with water
  7. customdried at 60° C.
  8. customto provide 7.6 parts by weight of the crude azo compound
  9. customThis crude azo compound (7 parts by weight) is recrystallized from n-propylalcohol

Sources & evidence

ORD record
ord-ef081558b2954ddfbdfa10169c55bd15
Source dataset
uspto-grants-1982_02
Patent number
US04315003

Reaction notes

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