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

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Reaction Steps

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).

Provenance & Evidence