Ethyl 8-methyl-2-oxo-2H-chromene-3-carboxylate synthesis

Yield:17349-63-2 78%

Reaction Conditions:

with piperidine;acetic acid in ethanol; for 0.0833333 h;Sonication;

Steps:

3-Ethoxycarbonylcoumarins 2-7; General Ultrasonic Procedure

General procedure: The 3-ethoxycarbonylcoumarin derivatives were prepared from a 1:1.1 mol ratio of the appropriate salicylaldehyde (500 mg, 4.1 mmol) and diethyl malonate (722 mg, 4.51 mmol) in absolute EtOH (2 mL). To this mixture, piperidine (34.5 mg, 0.4 mmol) and a catalytic amount of glacial AcOH were added. Ultrasonic irradiation was performed (frequency = 20 kHz, amplitude = 90% of the maximum power output) without a pulse for 5-30 min. After this period of time, hot H₂O (60 °C) (3 mL) was added, and after cooling the mixture at r.t., it was stored overnight in a refrigerator. The product was collected by filtration and washed with a solution of EtOH (1 mL) and distilled H₂O (2 mL). Finally, the product was washed with distilled H₂O (20 mL).

References:

Da Silveira Pinto, Ligia S.;De Souza, Marcus V. N. [Synthesis,2017,vol. 49,# 12,p. 2677 - 2682]