Microwave-assisted synthesis and antimicrobial activity of 5-trihalomethyl-3-arylisoxazoles

Synthesis of 5-(Fluoroalkyl)isoxazole Building Blocks by Regioselective Reactions of Functionalized Halogenoximes

A comprehensive study on the synthesis of 5-fluoroalkyl-substituted isoxazoles starting from functionalized halogenoximes is reported. One-pot metal-free [3 + 2] cycloaddition of CF3-substituted alkenes and halogenoximes bearing ester, bromo, chloromethyl, and protected amino groups was developed for the preparation of 5-trifluoromethylisoxazoles. The target 3,5-disubstituted derivatives were obtained in a regioselective manner in good to excellent yield on up to 130 g scale. 5-Fluoromethyl- and 5-difluoromethylisoxazoles were synthesized by late-stage deoxofluorination of the corresponding 5-hydroxymethyl or 5-formyl derivatives, respectively, in turn prepared via metal-free cycloaddition of halogenoximes and propargylic alcohol. An alternative approach based on nucleophilic substitution in 5-bromomethyl derivatives was found to be more convenient for the preparation of 5-fluoromethylisoxazoles. Reaction of isoxazole-5-carbaldehydes with the Ruppert-Prakash reagent was used for the preparation of (β,β,β-trifluoro-α-hydroxyethyl)isoxazoles. Utility of described approaches was shown by multigram preparation of side-chain functionalized mono-, di-, and trifluoromethylisoxazoles, for example, fluorinated analogues of ABT-418 and ESI-09.

Synthesis and characterization of new inhibitors of cholinesterases based on N-phenylcarbamates: In vitro study of inhibitory effect, type of inhibition, lipophilicity and molecular docking

Based on current treatment of Alzheimer's disease, where the carbamate inhibitor Rivastigmine is used, two series of carbamate derivatives were prepared: (i) N-phenylcarbamates with additional carbamate group (1-12) and (ii) N-phenylcarbamates with monosaccharide moiety (13-24). All compounds were tested for the inhibitory effect on both of the cholinesterases, electric eel acetylcholinesterase (eeAChE) and butyrylcholinesterase from equine serum (eqBChE) and the inhibitory activity (expressed as IC₅₀ values) was compared with that of the established drugs Galanthamine and Rivastigmine. The compounds with two carbamate groups 1-12 revealed higher inhibitory efficiency on both cholinesterases in compared with monosaccharide derived carbamates 13-24 and with Rivastigmine. The significant decrease of inhibitory efficiency on eqBChE (also for eeAChE but in less manner) was observed after deacetalization of monosaccharide. Moreover, the type of inhibitory mechanism of five chosen compounds was studied. It was found, that compounds with two carbamate groups act presumably via a mixed inhibitory mechanism and the compounds with monosaccharide moiety act as non-competitive inhibitors. The lipophilicity of tested compounds was determined using partition coefficient. Specific positions of the inhibitors in the binding sites of cholinesterases were determined using molecular modeling and the results indicate the importance of phenylcarbamate orientation in the catalytic gorges of both enzymes.

Biological potential of thiazolidinedione derivatives of synthetic origin

Thiazolidinediones are sulfur containing pentacyclic compounds that are widely found throughout nature in various forms. Thiazolidinedione nucleus is present in numerous biological compounds, e.g., anti-malarial, antimicrobial, anti-mycobacterium, anticonvulsant, antiviral, anticancer, anti-inflammatory, antioxidant, anti-HIV (human immunodeficiency virus) and antitubercular agent. However, owing to the swift development of new molecules containing this nucleus, many research reports have been generated in a brief span of time. Therefore seems to be a requirement to collect recent information in order to understand the current status of the thiazolidinedione nucleus in medicinal chemistry research, focusing in particular on the numerous attempts to synthesize and investigate new structural prototypes with more effective antidiabetic, antimicrobial, antioxidant, anti-inflammatory, anticancer and antitubercular activity.

Novel ibuprofenate- and docusate-based ionic liquids: emergence of antimicrobial activity

Six new ionic-liquid-based active pharmaceutical ingredients (IL-APIs) were prepared and their molecular structures characterized.

Unsaturated polyfluoroalkyl ketones in the synthesis of nitrogen-bearing heterocycles

This review focuses on the recent achievements and new developments in the synthesis of polyfluorinated aza-heterocycles based on fluorine-bearing enones and ynones published in the last decade.