A study on the physical properties of low melting mixtures and their use as catalysts/solvent in the synthesis of barbiturates

Abstract

In recent years, deep eutectic solvents have become attractive due to their interesting characteristics such as, physicochemical properties, low cost of components, easiness to prepare, low toxicity, bio‐renewability, and biodegradability. In order to make the deep eutectic mixture more cost‐effective and renewable, carbohydrate derivatives were linked with deep eutectic mixtures, since, carbohydrates are the most important and widespread renewable compounds on the earth. In this work, we have used low melting mixtures comprised of carbohydrates to create the reaction media for organic transformations. The physical properties such as density, viscosity, acidity, refractive index, surface tension, solubility, glass transition temperature, thermal stability, solvent polarity, and toxicity of the mixture were studied. Low melting mixtures were used as reaction media and catalysts for the effective synthesis of Barbiturates. The reaction between aldehydes and barbituric acid/thiobarbituric acid, and the reaction between aldehydes, barbituric acid/thiobarbituric acid, and malononitrile/dimedone were performed effectively with good to excellent yields. The recyclability of the catalyst/solvent was also established.

L‐proline‐based DES in Knoevenagel synthesis of arylidene rhodanines, thiazolidine‐2,4‐diones, and barbituric derivatives

“…Thus, Tipale et al described the synthesis of pyrazolopyranopyrimidines [27] via a four‐component domino synthesis in ChCl:urea DES whereas Monem et al synthesized pyrano[2,3‐d]pyrimidines in a new hypogallic acid‐based DES [28]. Theresa et al developed and characterized two new DES efficient for Knoevenagel condensation of barbituric acid and multicomponent reaction: Tartaric acid:ChCl and Glucose:ChCl [29]. Glycolic acid: urea can also be used to perform Knoevenagel condensation of barbituric acid at room temperature whereas polycyclic compounds can be obtained in the same DES when reaction was performed in presence of two equivalents of barbituric acid and aldehydes at 80°C [30].…”

Synthesis of 5-arylidenerhodanines in L-proline-based deep eutectic solvent

“…On the other hand, Pro/Gly DES may also activate carbonyl groups as suggested by Mohire et al [ 23 ] and Theresa et al . [ 24 ]. In any event, the DES structure in Pro/Gly seems to play an important role in promoting the reaction.…”

Design, Synthesis and Characterization of Aurone Based α,β‐unsaturated Carbonyl‐Amino Ligands and their Application in Microwave Assisted Suzuki, Heck and Buchwald Reactions

“…5‐(4‐methoxybenzylidene)pyrimidine‐2,4,6(1H,3H,5H)‐trione (9 b) : [62] Yellow Solid; Yield 84%; m. p 275–276 °C; 1 H NMR (400 MHz, CDCl 3 +DMSO‐d 6 ) δ 10.51 (d, J =47.6 Hz, 2H), 7.67–7.61 (m, 3H), 6.28 (d, J =8.2 Hz, 2H), 3.20 (s, 3H); 13 C NMR (100 MHz, CDCl 3 +DMSO‐d 6 ) δ 163.77, 163.51, 161.86, 155.99, 150.00, 137.50, 124.91, 114.57, 113.53, 55.27.…”