Theoretical 14N nuclear quadrupole resonance parameters for sulfa drugs: Sulfamerazine and sulfathiazole

Development in the Synthesis of Bioactive Thiazole-Based Heterocyclic Hybrids Utilizing Phenacyl Bromide

Heterocyclic hybrid frameworks represent a burgeoning domain within the realms of drug discovery and medicinal chemistry, attracting considerable attention in recent years. Thiazole pharmacophore fragments, inherent in natural products such as peptide alkaloids, metabolites, and cyclopeptides, have demonstrated a broad spectrum of pharmacological potentials. Given their profound biological significance, a plethora of thiazole-based hybrids have been synthesized through the conjugation of thiazole moieties with bioactive pyrazole and pyrazoline fragments. This review systematically presents a compendium of robust methodologies for the synthesis of thiazole-linked hybrids, employing the (3 + 2) heterocyclization reaction, specifically the Hantzsch-thiazole synthesis, utilizing phenacyl bromide as the substrate. The strategic approach of molecular hybridization has markedly enhanced drug efficacy, mitigated resistance to multiple drugs, and minimized toxicity concerns. The resultant thiazole-linked hybrids exhibit a myriad of medicinal properties viz. anticancer, antibacterial, anticonvulsant, antifungal, antiviral, and antioxidant activities. This compilation of methodologies and insights serves as a valuable resource for medicinal chemists and researchers engaged in the design of novel thiazole-linked hybrids endowed with therapeutic attribute.

The enhancing effect of a cation-π interaction on the cooperativity of halogen bonds: A computational study

In this work, we investigate the effect of a cation-π interaction on the cooperativity of X⋯N halogen bonds in PhX⋯NCX⋯NH₃ complexes, where Ph=phenyl and X=Cl, Br, I. Molecular geometries and interaction energies of the resulting complexes are studied at the MP2/aug-cc-pVDZ(-PP) computational level. The mechanism of the cooperativity between halogen bonds is analyzed using parameters derived from the noncovalent index, quantum theory of atoms in molecules and natural bond orbital methodologies. It is found that the divalent cations (Be²⁺, Mg²⁺) have a larger influence on the cooperativity of halogen bonds than monovalent ones (Li⁺, Na⁺). The formation of a cation-π interaction leads to strengthening of the halogen bonds, hence increases their cooperativity.

Halogen bond interactions enhanced by sodium bonds — Theoretical evidence for cooperative and substitution effects in NCX···NCNa···NCY complexes (X = F, Cl, Br, I; Y = H, F, OH)

Quantum chemical calculations are performed to study cooperativity and substituent effects between halogen bond and sodium bond interactions in NCX···NCNa···NCY complexes, where X = F, Cl, Br, I and Y = H, F, OH. These effects are studied in terms of equilibrium geometry, interaction energy, 15N nuclear magnetic resonance (NMR) parameters, and electron density analysis of the complexes at the MP2/aug-cc-pVTZ level. The X···N and Na···N bond lengths in the ternary systems are always shorter than those in the corresponding dyads. In each triad, the decrease in the halogen bond length is far greater than that of the sodium bond. In all triads studied, a favorable cooperativity is found with values that range between –0.30 and –1.72 kcal/mol. It is revealed that NMR parameters at the site of the nitrogen atom of the NCNa molecule can be regarded as a good description to quantify the degree of cooperative effects in the NCX···NCNa···NCY systems. The nature of halogen bond and sodium bond interactions of the complexes is analyzed using parameters derived from the quantum theory of atoms in molecules methodology and energy decomposition analysis.