Ethanol → 8-(3,5-Dimethoxy-phenyl)-quinoxaline-5-carboxylic acid ethyl ester

HRID 43155Notes

Reaction equation

HRID 43155 reaction equation
[CH3:1][O:2][C:3]1[CH:4]=[C:5]([C:11]2[C:20]3[N:19]=[CH:18][CH:17]=[N:16][C:15]=3[C:14]([C:21]([OH:23])=[O:22])=[CH:13][CH:12]=2)[CH:6]=[C:7]([O:9][CH3:10])[CH:8]=1.OS(O)(=O)=O.[CH3:29][CH2:30]O>>[CH2:29]([O:22][C:21]([C:14]1[C:15]2[N:16]=[CH:17][CH:18]=[N:19][C:20]=2[C:11]([C:5]2[CH:4]=[C:3]([O:2][CH3:1])[CH:8]=[C:7]([O:9][CH3:10])[CH:6]=2)=[CH:12][CH:13]=1)=[O:23])[CH3:30]

Participants

4

Reactant 3

HCID 702EthanolHCID 1118Sulfuric AcidHCID 592928448-(3,5-Dimethoxy-phenyl)-quinoxaline-5-carboxylic acid

Product 1

HCID 669146908-(3,5-Dimethoxy-phenyl)-quinoxaline-5-carboxylic acid ethyl ester

Procedure

A mixture of 8-(3,5-dimethoxy-phenyl)-quinoxaline-5-carboxylic acid (Step 1.2) (10 g), H2SO4 conc. (3 mL) and EtOH (500 mL) was stirred at reflux for 7 h, allowed to cool and concentrated. The residue was diluted in EtOAc and a saturated aqueous solution of NaHCO3. The aqueous phase was separated and extracted with EtOAc. The combined organic layers were washed with H2O and brine, dried (Na2SO4), filtered and concentrated to afford 10.1 g of the title compound as a beige solid. Title compound: ESI-MS: 339.2 [M−H]−; tR=4.72 min (System 1).

Workup

  1. temperatureat reflux for 7 h
  2. temperatureto cool
  3. concentrationconcentrated
  4. additionThe residue was diluted in EtOAc
  5. customThe aqueous phase was separated
  6. extractionextracted with EtOAc
  7. washThe combined organic layers were washed with H2O and brine
  8. dry with materialdried (Na2SO4)
  9. filtrationfiltered
  10. concentrationconcentrated

Sources & evidence

ORD record
ord-7019cb34348f43a39a7f0a37503ccf86
Source dataset
uspto-grants-2013_09
Patent number
US08536175B2

Reaction notes

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