Hydrochloric Acid → m-(2-Carboxy-4-amino-phenylazo)benzenephosphonic acid

HRID 51979

Reaction equation

HRID 51979 reaction equation
[NH2:1][C:2]1[CH:3]=[C:4]([P:8]([OH:11])(=[O:10])[OH:9])[CH:5]=[CH:6][CH:7]=1.Cl.N([O-])=O.[Na+].N[C:18]([NH2:20])=S.[NH2:21][C:22]1[CH:23]=[C:24](C=[CH:29][CH:30]=1)[C:25]([OH:27])=[O:26]>CO.O>[C:25]([C:24]1[CH:23]=[C:22]([NH2:21])[CH:30]=[CH:29][C:18]=1[N:20]=[N:1][C:2]1[CH:3]=[C:4]([P:8]([OH:11])(=[O:9])[OH:10])[CH:5]=[CH:6][CH:7]=1)([OH:27])=[O:26]

Participants

8

Reactant 5

HCID 313Hydrochloric AcidHCID 74193-Aminobenzoic AcidHCID 79477Phosphonic acid, P-(3-aminophenyl)-2×HCID 2723790ThioureaHCID 23668193Sodium Nitrite

Product 1

HCID 19962636m-(2-Carboxy-4-amino-phenylazo)benzenephosphonic acid

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 962WaterSolvent

Conditions

Temperature
0 °C

Procedure

Into water (500 ml), m-aminobenzenephosphonic acid (87.0 g) was suspended with stirring. To the mixture, 35% hydrochloric acid (101.3 g) was added, and the mixture was cooled to 0° C. While the solution was maintained at a temperature below 5° C., 36% sodium nitrite (105.4 g) was added dropwise to the solution. The mixture was stirred for 50 minutes to diazotize m-aminobenzenephosphonic acid. Thiourea was then added to the resulting aqueous solution, and the unreacted nitrite was removed to give a diazotized compound containing solution. On the other hand, 3-aminobenzoic acid (58.6 g) was dispersed into methanol (800 ml) and heated to 55° C. to form a solution containing a coupling compound, which was then cooled to 0° C. The diazotized compound containing solution prepared above was added dropwise while the mixture was maintained at a temperature below 5° C. After stirring the mixture at 3°-5° C. for 18 hours, the resulting precipitates were collected by filtration, washed with water to give a monoazo compound, m-(2-carboxy-4-amino-phenylazo)benzenephosphonic acid in a yield of about 125.3 g.

Workup

  1. additionwas added dropwise to the solution
  2. stirringThe mixture was stirred for 50 minutes
  3. customthe unreacted nitrite was removed
  4. customto give a diazotized compound
  5. additioncontaining solution
  6. temperatureheated to 55° C.
  7. customto form a solution
  8. additioncontaining a coupling compound, which
  9. temperaturewas then cooled to 0° C
  10. additionThe diazotized compound containing solution
  11. customprepared
  12. additionabove was added dropwise while the mixture
  13. temperaturewas maintained at a temperature below 5° C
  14. stirringAfter stirring the mixture at 3°-5° C. for 18 hours
  15. customthe resulting precipitates
  16. filtrationwere collected by filtration
  17. washwashed with water

Sources & evidence

ORD record
ord-799b3867a63b4adca91cfb16516fc559
Source dataset
uspto-grants-1997_04
Patent number
US05616174

Linked notes

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