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The present methodology explored the effectiveness and versatility of deep eutectic solvent with ultrasonic energy as an eco-friendly protocol for the synthesis of bisthioglycolic acid derivatives. Bisthioglycolic moiety holds its role as a potent scaffold in sulfur-containing drugs. The presented strategy offers significant advantages such as green catalyst as well as solvent, excellent yield, short reaction time, and simple reaction workup. This methodology shows a wide range of substrate scope that contain both electron-donating as well as electron-withdrawing groups. [ABSTRACT FROM AUTHOR]

Green chemistry is the basis for fast‐growing, eco‐friendly, alternative sustainable technologies for the development of chemical products without the use or generation of hazardous catalysts. The role of naturally occurring fruit juice as a catalyst or solvent in organic synthesis has gained focused interest across the globe. Lemon juice‐mediated synthesis has been widely explored recently as a highly significant, selective solvent and biocatalyst in organic synthesis. This review presents recent developments on lemon‐juice mediated transformations and their application to synthesize molecules or building blocks of pharmaceutical interest. We believe this review article will be of interest to researchers both in academic and industrial settings focused on developing novel pharmacophores from a green chemistry principles perspective. [ABSTRACT FROM AUTHOR]

The article examines the utilization of the replica exchange molecular dynamics (REMD) methodology to analyze the conformational space of Neuromedin C (NMC) using implicit and explicit REMD water models. Results suggest that REMD explicit trajectory has a greater tendency to induce β-turns and bent structures than those observed in REMD implicit simulation. Additional molecular dynamic trajectories using Langevin and Berendsen algorithms under generalized born solvent showed competence to sample similar conformations.

Solvents play a stabilising role with the more stable conformations obtained in polar solvents than in vacuo. We investigate to what extent the structural propensities of the pentacyclo-undecane (PCU) cage polypeptide chain of the type Ac-3Aib-Cage-3Aib-NHMe are influenced in implicit water and in explicit solvents: methanol (MEOH), dimethyl sulphoxide (DMSO) and TIP3P water. The sampling of the α-helical conformations of the PCU cage polypeptide was investigated using the in-house modified PARM94 force-field parameters. Analysis of 50 ns molecular dynamics (MD) simulations revealed a tendency of the PCU cage polypeptide to assume bent structures, especially in polar solvents. The choice of solvents was designed to relate the simulations to physiological conditions. The individual amino-isobutyric acid residues predominantly sampled the right-handed and left-handed 310-helical conformations, indicating that the helical conformations are preferred in all four environments (in vacuo, MEOH, water and DMSO). Additionally, the 100 ns replica exchange MD (REMD) simulations of the PCU cage polypeptide in implicit water revealed more conformational variety present than in explicit solvents, and is more consistent with previous theoretical studies on the PCU cage residue. The present theoretical results may help in rationalising experimental results on these PCU cage polypeptides, and definitely show the importance of a dynamical approach for a correct interpretation and prediction of the conformational behaviour of the PCU cage molecules in different environments. [ABSTRACT FROM AUTHOR]

Ab initio and density functional theory (DFT) calculations have been used to investigate the feasibility of cycloaddition reactions of enaminones 1 with sulphene. Specifically, the geometry optimizations, frequency calculations and self-consistent reaction-field (SCRF) solvent simulations in combination with higher-quality relative energies carried out at the DFT level using the 6-31+G(d) basis set suggests that the product obtained is both thermodynamically and kinetically preferred, indicating the feasibility of this reaction. Additionally, experimental studies carried out on the reactions of these enaminones 1 with sulphene were also found to be in agreement with the theoretical predictions resulting in the synthesis of a variety of novel oxathiine derivatives having great biological and medicinal importance. [ABSTRACT FROM AUTHOR]

Abstract: The comparative account of the reactivities of N′-[(5-benzoyl and ethoxycarbonyl)thiazol-2-yl]-N,N-dimethylformamidines ( 1a and 1b ), tremendously influenced by the electronic nature of the substituents on C-5 of the thiazolic ring with various monosubstituted and conjugated ketenes is reported herein. The DA cycloadditions of the dienyl pyrimidinone 3h with both symmetrical as well as unsymmetrical dienophiles leading to the formation of various thiazolic pyrimidinone derivatives are also reported. [Copyright &y& Elsevier]

A green, sustainable, and efficient one-pot, synthetic strategy for the synthesis of 2,3-dihydroquinazolin-4(1H)-ones (DHQs) was developed. The ZnCl2/urea used as a deep eutectic solvent (DES) not only efficiently promoted the condensation between isatoic anhydride and benzaldehyde but unexpectedly acted as a nitrogen source (like ammonia) in situ to afford DHQs in excellent yields. This approach offers remarkable advantages, involving the triple role of DES in the synthesis of DHQs, atom-economical, green organocatalysts, metal-free conditions, cost-effectiveness, and tolerance to a range of functional groups. [ABSTRACT FROM AUTHOR]