Hydrochloric Acid → 6-Chloronaphthalene-2-carboxylic acid

HRID 1270770Notes

Reaction equation

HRID 1270770 reaction equation
N([O-])=O.[Na+].S(=O)(=O)(O)O.N[C:11]1[CH:12]=[C:13]2[C:18](=[CH:19][CH:20]=1)[CH:17]=[C:16]([C:21]([OH:23])=[O:22])[CH:15]=[CH:14]2.O.[ClH:25]>C(O)(=O)C.[Cu]Cl>[Cl:25][C:11]1[CH:12]=[C:13]2[C:18](=[CH:19][CH:20]=1)[CH:17]=[C:16]([C:21]([OH:23])=[O:22])[CH:15]=[CH:14]2

Participants

8

Reactant 5

HCID 313Hydrochloric AcidHCID 962WaterHCID 1118Sulfuric AcidHCID 27339546-Aminonaphthalene-2-carboxylic acidHCID 23668193Sodium Nitrite

Product 1

HCID 132883276-Chloronaphthalene-2-carboxylic acid

Reagents, catalysts & solvents 2

HCID 62652Cuprous chlorideCatalystHCID 176Acetic AcidSolvent

Conditions

Temperature
70 °C

Procedure

Sodium nitrite (811 mg, 11.8 mmol) is added over a period of 15 minutes to concentrated sulfuric acid (10 mL) while stirring. The mixture is heated to 70° C. for 15 minutes. After cooling to room temperature, a solution of 6-amino-2-naphthoic acid (2 g, 10.7 mmol) in acetic acid (10 mL) is added dropwise at such a rate that the temperature is kept below 40° C. After stirring at 40° C. for an additional 30 minutes, the reaction mixture is poured into an ice-cooled solution of copper(I) chloride (2.54 g, 25.6 mmol) in concentrated HCl (30 mL). After stirring at 80° C. for 30 minutes, water (80 mL) is added. The precipitate is collected and purified by flash chromatography on silica gel (5% methanol in dichloromethane) to give 6-chloro-2-naphthoic acid as a brown solid.

Workup

  1. temperatureAfter cooling to room temperature
  2. customis kept below 40° C
  3. stirringAfter stirring at 40° C. for an additional 30 minutes
  4. stirringAfter stirring at 80° C. for 30 minutes
  5. customThe precipitate is collected
  6. custompurified by flash chromatography on silica gel (5% methanol in dichloromethane)

Sources & evidence

ORD record
ord-82cc6365613241269742c37fcad03529
Source dataset
uspto-grants-2007_04
Patent number
US07202364B2

Reaction notes

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