Abstract
A rapid and efficient procedure for the synthesis of quinoxaline derivatives has been achieved by condensation of aryl-1,2-diamines with 1,2-dicarbonyl compounds catalyzed by polyethylene glycol under CEM-focused microwave-irradiation conditions.
ACKNOWLEDGMENTS
The work was supported by the Natural Science Foundation of China (Grant Nos. 20272047 and 20572086), the Gansu Natural Science Foundation of China (No. 0308RJZA-100), and the Key Laboratory of Eco-environment-Related Polymer Material (Northwest Normal University), Ministry of the Education of China.
Notes
a Reaction conditions: 4-methylbenzene-1,2-diamine (2.0 mmol), benzil (2.0 mmol), and catalyst irradiating under CEM focused microwave for 3 min at 200 W and 120 °C.
b Isolated yield.
a Reaction conditions: 4-methylbenzene-1,2-diamine (2.0 mmol), benzil (2.0 mmol), and PEG (0.3 mmol) irradiating under focused microwaves.
b Isolated yield.
c Reactions were performed with an improved reflux microwave oven.
d Conventional heating was used, and the reaction was stirred in an oil bath at 120 °C.
a All reactions were conducted in the same conditions: amines (2 mmol), ketones (2 mmol), PEG (0.3 mmol), P = 200 W if both the substrates are solid or P = 10 W if one of the substrates is liquid, at 120 °C for the appropriate time.
b Isolated yields.