Hydrochloric Acid → 7-Chloronaphthalene-2-sulfonic acid

HRID 528796Notes

Reaction equation

HRID 528796 reaction equation
N[C:2]1[CH:11]=[C:10]2[C:5]([CH:6]=[CH:7][C:8]([S:12]([O-:15])(=[O:14])=[O:13])=[CH:9]2)=[CH:4][CH:3]=1.[Na+].N([O-])=O.[Na+].[ClH:21]>O.Cl[Cu]>[Cl:21][C:2]1[CH:11]=[C:10]2[C:5]([CH:6]=[CH:7][C:8]([S:12]([OH:15])(=[O:14])=[O:13])=[CH:9]2)=[CH:4][CH:3]=1

Participants

6

Reactant 3

HCID 313Hydrochloric Acid2×HCID 23668193Sodium NitriteHCID 236786932-Naphthalenesulfonic acid, 7-amino-, monosodium salt

Product 1

HCID 199856837-Chloronaphthalene-2-sulfonic acidYield 85%

Reagents, catalysts & solvents 2

HCID 62652Cuprous chlorideCatalystHCID 962WaterSolvent3×

Procedure

A solution of sodium 7-aminonaphthalene-2-sulfonate (Pfaltz and Bauer, 1.00 g, 4.08 mmol) in water (6.0 mL) and conc. HCl (6.0 mL) was cooled to 0° C. A premixed solution of NaNO2 (295 mg, 4.28 mmol) in water (3.0 mL) was added slowly, maintaining the temperature close to 0° C. The resulting reaction mixture was stirred at room temperature for 30 min. A solution of CuCl (807 mg, 8.16 mmol) in water (1.0 mL) and conc. HCl (4.0 mL) was then added dropwise over 30 min, maintaining the temperature close to 0° C. The reaction mixture was stirred at room temperature for 2 h, then concentrated in vacuo and dissolved in a small amount of water. The solids were filtered off and retained. The filtrate was concentrated in vacuo, purified by preparative HPLC and combined with the filtered solids to give the title compound (843 mg, 85%) as a dark grey solid. MS(ESI−) m/z 241.2 (M−H)−.

Workup

  1. temperaturemaintaining the temperature
  2. customclose to 0° C
  3. customThe resulting reaction mixture
  4. temperaturemaintaining the temperature
  5. customclose to 0° C
  6. stirringThe reaction mixture was stirred at room temperature for 2 h
  7. concentrationconcentrated in vacuo
  8. dissolutiondissolved in a small amount of water
  9. filtrationThe solids were filtered off
  10. concentrationThe filtrate was concentrated in vacuo
  11. custompurified by preparative HPLC

Sources & evidence

ORD record
ord-4e3e81f03de2424b9af98a644d10a3ec
Source dataset
uspto-grants-2016_05
Patent number
US09346795B2

Reaction notes

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