Nucleophilic phenylation: a remarkable application of alkoxymethyltriphenylphosphonium salts

Benzimidazolium quaternary ammonium salts: synthesis, single crystal and Hirshfeld surface exploration supported by theoretical analysis

Owing to the broad applications of quaternary ammonium salts (QAS), we present the synthesis of benzimidazolium-based analogues with variation in the alkyl and alkoxy group at N-1 and N-3 positions. All the compounds were characterized by spectroscopic techniques and found stable to air and moisture both in the solid and solution state. Moreover, molecular structures were established through single-crystal X-ray diffraction studies. The crystal packing of the compounds was stabilized by numerous intermolecular interactions explored by Hirshfeld surface analysis. The enrichment ratio was calculated for the pairs of chemical species to acquire the highest propensity to form contacts. Void analysis was carried out to check the mechanical response of the compounds. Furthermore, theoretical investigations were also performed to explore the optoelectronic properties of compounds. Natural population analysis (NPA) has been conducted to evaluate the distribution of charges on the synthesized compounds, whereas high band gaps of the synthesized compounds by frontier molecular orbital (FMO) analysis indicated their stability. Nonlinear optical (NLO) analysis revealed that the synthesized QAS demonstrates significantly improved NLO behaviour than the standard urea.

New azole-derived hemiaminal ethers as promising acetylcholinesterase inhibitors: synthesis, X-ray structures, in vitro and in silico studies

A new class of azole-derived hemiaminal ethers is designed as acetylcholinesterase (AChE) inhibitors. The synthesized compounds exhibited remarkable inhibitory activity against acetylcholine. Chiral hemiaminals (3d and 3i) based on (R)-menthoxymethyl group exhibit excellent inhibition with IC50 values of 0.983 ± 1.41 and 1.154 ± 0.89 µM. Similarly, butoxymethyl derivatives 3a, 3f and 3h, also showed promising inhibition comparable to the standard drug, Donepezil. In silico studies were performed to understand the mode of interactions with the target proteins, where menthoxymethyl azoles 3d and 3i demonstrated the highest docking scores. Molecular dynamics simulations displayed the stable ligand-protein complex of 3i with effective binding interactions. The bioavailability and pharmacokinetic parameterssupported the suitability of these small molecule inhibitors to develop cost-effective drug leads for Alzheimer's disease (AD). MTT assay substantiated the non-cytotoxic nature of the compounds. The synthesized compounds are extensively characterized by 1H NMR, 13C NMR and mass spectral data and SC-XRD.Communicated by Ramaswamy H. Sarma.

Lewis Acid-Catalyzed Synthesis of Alkoxymethylhalides for Multipurpose Mixed Acetals; Scope and Limitations

Abstract:

The work describes a detailed account of the Lewis acid-catalyzed preparation of structurally variant alkoxymethyl halides. A series of Lewis acids with different halogenating agents areevaluatedfor the cleavage of bis-alkoxymethanes, where several readily available Lewis acids were found to exhibit high catalytic potential. SOCl2 with MgCl2 was found one of the best combinations for facile and efficient preparation of structurally diverse alkoxymethyl halides under solvent-free conditions. The efficacy of the methodology was established to obtain a wide range of mixed acetals through alkoxymethylation of phosphorus, sulfur, nitrogen, and oxygen containing nucleophiles. The present procedure has significant advantages including simplicity, generality, rapidity, and availability of reagents.