Effectual sonochemical synthesis of pyrido-dipyrimidines in a green and reproducible deep eutectic solvent

Abstract

In this work, one-pot pseudo four-component synthesis of pyrido[2,3-d:6,5-d′]dipyrimidines from various aldehydes (1 mmol), 2-thiobarbituric acid (2 mmol), and ammonium acetate (1.2 mmol) in deep eutectic solvent (DES) named ChCl/THFTCA (choline chloride and tetrahydrofuran-2,3,4,5-tetracarboxylic acid) has been developed under ultrasonic irradiation. A wide range of pyrido-dipyrimidines can be synthesized with excellent performance in the biodegradable eutectic solvent ChCl/THFTCA-DES under optimized conditions (1 mL of DES, 25 °C, ultrasonic: 30 W), which is simple in operation and compatible with functional groups (1a-17a, 9–20 min, 89–98%). The DES both acts as a green medium for this reaction and as a catalyst, and can be recovered and reused up to six times with negligible activity loss. Also, green chemistry metrics were merged in this method, confirming its adherence to sustainable synthesis approaches and emphasizing its environmental compatibility. Synthesis and characterization of novel derivatives, brilliant metrics of green chemistry, introducing an efficient catalytic system by integrating the catalytic effect of a DES and ultrasonic irradiation, and the first report of the synthesis of the above derivatives in an efficient DES according to our research are the novel aspects of our approach.

Graphical abstract