Sulfuric Acid → 7-Methoxyquinolin-8-ol

HRID 280012Notes

Reaction equation

HRID 280012 reaction equation
[CH3:1][O:2][C:3]1[C:12]([O:13]C)=[C:11]2[C:6]([CH:7]=[CH:8][C:9](C(O)=O)=[N:10]2)=[CH:5][CH:4]=1.S(=O)(=O)(O)O.[OH-].[Na+]>>[OH:13][C:12]1[C:3]([O:2][CH3:1])=[CH:4][CH:5]=[C:6]2[C:11]=1[N:10]=[CH:9][CH:8]=[CH:7]2

Participants

4

Reactant 3

HCID 1118Sulfuric AcidHCID 14798Sodium HydroxideHCID 201297637,8-Dimethoxyquinoline-2-carboxylic acid

Product 1

HCID 128498147-Methoxyquinolin-8-olYield 53.1%

Procedure

Finely ground 7,8-dimethoxyquinoline-2-carboxylic acid (1.00 g, 4.3 mmol) (W. Ried, A. Berg and G. Schmidt, Chem. Ber., 85, 204 (1952)) was heated under nitrogen in a flask submerged in an oil batch at 185° until the evolution of gases had ceased from the melt. The reaction was cooled and 75% aqueous sulfuric acid (8.1 mL) was carefully added. The resulting solution was heated at 105°-125° for 2 hr, cooled, poured over ice and taken to pH 5 with 5N sodium hydroxide. The mixture was filtered, and the filtrate was extracted with methylene chloride (4×50 mL). The extracts were dried (MgSO4) and concentrated in vacuo to give 8-hydroxy-7-methoxyquinoline (0.40 g, 53%), mp 113°-115° after recrystallization from 95% ethanol. Anal. Calcd for C10H9NO2 : C, 68.56; H, 5.18; N, 8.00. Found: C, 68.33; H, 5.17; N, 7.97.

Workup

  1. temperature, 85, 204 (1952)) was heated under nitrogen in a flask
  2. customsubmerged in an oil batch at 185° until the evolution of gases
  3. temperatureThe reaction was cooled
  4. temperatureThe resulting solution was heated at 105°-125° for 2 hr
  5. temperaturecooled
  6. additionpoured over ice
  7. filtrationThe mixture was filtered
  8. extractionthe filtrate was extracted with methylene chloride (4×50 mL)
  9. dry with materialThe extracts were dried (MgSO4)
  10. concentrationconcentrated in vacuo

Sources & evidence

ORD record
ord-460bcaf8d8cc48e0955342dd656d91ec
Source dataset
uspto-grants-1986_05
Patent number
US04587342

Reaction notes

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