FeCl₃ and Morpholine as Efficient Cocatalysts for the One-Step Synthesis of Quinoxalines from α-Hydroxyketones and 1,2-Diamines

Abstract

One-step conversion including intramolecular hydrogen bond decomposition, aerobic oxidation, and condensation from α-hydroxyketones and 1,2-diamines into quinoxalines is reported using FeCl₃ and morpholine as cocatalysts.

GRAPHICAL ABSTRACT

Keywords:

• Cocatalyst
• FeCl₃
• morpholine
• quinoxaline

Notes

^a Reaction conditions: o-phenylenediamine 1a (2 mmol), benzoin 2a (2 mmol), EtOH (5 mL), 80 °C.

^b Isolated yield after column chromatography.

^c The reaction was performed in EtOH at room temperature.

^a Reaction conditions: o-phenylenediamine la (2 mmol), benzoin 2a (2 mmol), EtOH (5 mL), 80 °C.

^b Isolated yield.

^c The reaction was performed in CH₂C1₂ at room temperature.

^d No reaction was observed.

^a Unless otherwise specified, all reactions were performed with 2a (1 mmol) and 20 mol% of catalyst in EtOH (2 mL) at 80 °C for 1 h.

^b Isolated yield.

^c The reaction was performed under Ar protection conditions.

^d No reaction was observed.