Hydrochloric Acid → 5-Amino-3-mercapto-4-phenoxybenzoic acid

HRID 1605512Notes

Reaction equation

HRID 1605512 reaction equation
[Na].[N+:2]([C:5]1[C:6]([O:17][C:18]2[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=2)=[C:7]([S:14](O)=O)[CH:8]=[C:9]([CH:13]=1)[C:10]([OH:12])=[O:11])([O-])=O.Cl>C(O)C.[Zn]>[NH2:2][C:5]1[C:6]([O:17][C:18]2[CH:19]=[CH:20][CH:21]=[CH:22][CH:23]=2)=[C:7]([SH:14])[CH:8]=[C:9]([CH:13]=1)[C:10]([OH:12])=[O:11]

Participants

6

Reactant 3

HCID 313Hydrochloric AcidHCID 5360545SodiumHCID 215201035-Nitro-4-phenoxy-3-sulfinobenzoic acid

Product 1

HCID 215201075-Amino-3-mercapto-4-phenoxybenzoic acid

Reagents, catalysts & solvents 2

HCID 23994ZincCatalystHCID 702EthanolSolvent

Procedure

Zinc powder (38 g) is added to a warm solution (70° C) of the mono sodium salt of 5-nitro-4-phenoxy-3-sulfinobenzoic acid (10 g) in ethanol (190 ml), and while stirring 5 N hydrochloric acid (190 ml) is added dropwise. The reaction mixture is kept under nitrogen for an additional 2 hours at 70° C. After cooling and filtration, the ethanol is distilled off in vacuo. After standing in a refrigerator for 16 hours, the precipitated material is collected by filtration and washed with concentrated hydrochloric acid (15 ml). This material is then suspended in water (300 ml) and the pH adjusted to 2 by addition of 2 N sodium hydroxide. The obtained crude 5-amino-3-mercapto-4-phenoxybenzoic acid is collected and recrystallized from aqueous ethanol. The acid is obtained with a melting point of 199°-200° C.

Workup

  1. additionis added dropwise
  2. temperatureAfter cooling
  3. filtrationfiltration
  4. distillationthe ethanol is distilled off in vacuo
  5. waitAfter standing in a refrigerator for 16 hours
  6. filtrationthe precipitated material is collected by filtration
  7. washwashed with concentrated hydrochloric acid (15 ml)
  8. additionthe pH adjusted to 2 by addition of 2 N sodium hydroxide

Sources & evidence

ORD record
ord-56a4b015893047a89ea4abb5f019fa9d
Source dataset
uspto-grants-1976_04
Patent number
US03950376

Reaction notes

Loading…