Greener approach for synthesis of novel steroidal prodrugs using ionic liquid, their DFT study and apoptosis activity in prostate cancer cell line

Unravelling the optical properties and self-assembly behavior of ciprofloxacin in ionic liquid environments: probing the role of cationic residues and counter anions

This study investigated the interaction of ciprofloxacin (CIP) with three different ionic liquids (ILs) featuring distinct cationic residues (pyrrolidinium, IL1, vs. imidazolium, IL2, with bis(trifluoromethylsulfonyl)imide as the counter anion) and counter anions bis(trifluoromethylsulfonyl)imide, IL2, vs. hexafluorophosphate, IL3, with imidazolium as the cationic residue) in an aqueous environment. A series of spectroscopic studies have been performed to elucidate the role of ILs in the optical properties as well as aggregation behavior of CIP. The fluorescence quenching experiment indicated that the IL with a pyrrolidinium residue showed stronger binding with CIP, while bis(trifluoromethylsulfonyl)imide was the preferred anion. These quenching effects might be attributed to complex formation mediated by charge-pair and cation-π interactions, along with hydrogen bonding. The Stern-Volmer analysis confirmed a static quenching mechanism, with binding constants (Kb) reflecting the stronger affinity of IL1 due to the hydrophobic butyl group and the flexible pyrrolidinium cation, resulting in the formation of larger aggregates. In contrast, the imidazolium residue in IL2 facilitated π-π and hydrogen-bond interactions, disrupting CIP aggregation and resulting in smaller clusters. The polarizable nature of bis(trifluoromethylsulfonyl)imide along with its hydrogen bond-accepting ability enabled stronger binding of ILs containing this anion to CIP compared to hexafluorophosphate-containing ILs. Further studies indicated that pH 6 is optimum for CIP-IL interactions, where CIP remained in its zwitterionic form. Increased temperature and ionic strength diminished the quenching efficiency, consistent with the reduced stability of CIP-IL complexes under such conditions.

Synthesis of Anti-Inflammatory Spirostene-Pyrazole Conjugates by a Consecutive Multicomponent Reaction of Diosgenin with Oxalyl Chloride, Arylalkynes and Hydrazines or Hydrazones

Steroid sapogenin diosgenin is of significant interest due to its biological activity and synthetic application. A consecutive one-pot reaction of diosgenin, oxalyl chloride, arylacetylenes, and phenylhydrazine give rise to steroidal 1,3,5-trisubstituted pyrazoles (isolated yield 46–60%) when the Stephens–Castro reaction and heterocyclization steps were carried out by heating in benzene. When the cyclization step of alkyndione with phenylhydrazine was performed in 2-methoxyethanol at room temperature, steroidal α,β-alkynyl (E)- and (Z)-hydrazones were isolated along with 1,3,5-trisubstituted pyrazole and the isomeric 2,3,5-trisubstituted pyrazole. The consecutive reaction of diosgenin, oxalyl chloride, phenylacetylene and benzoic acid hydrazides efficiently forms steroidal 1-benzoyl-5-hydroxy-3-phenylpyrazolines. The structure of new compounds was unambiguously corroborated by comprehensive NMR spectroscopy, mass-spectrometry, and X-ray structure analyses. Performing the heterocyclization step of ynedione with hydrazine monohydrate in 2-methoxyethanol allowed the synthesis of 5-phenyl substituted steroidal pyrazole, which was found to exhibit high anti-inflammatory activity, comparable to that of diclofenac sodium, a commercial pain reliever. It was shown by molecular docking that the new derivatives are incorporated into the binding site of the protein Keap1 Kelch-domain by their alkynylhydrazone or pyrazole substituent with the formation of more non-covalent bonds and have higher affinity than the initial spirostene core.

Evaluation of Pipemidic Acid Derivatives for Potential Antimicrobial Activity Application: In silico Studies on Bioactivity

Background:

Pipemidic acid is a broad-spectrum quinolone antibacterial agent for the treatment of chronic urinary tract infections against both gram-positive and gram-negative bacteria. Both quinolone and fluoroquinolone antibiotics have been useful in combating bacterial infections. However, patients suffer severe side effects when they stop taking the medication. The piperazinyl region of pipemidic acid is highly responsible for the side effects.

Objective:

The objective of this study is to design new compounds in which the piperazinyl region is masked by way of conjugation to benzoic acid derivatives.

Methods:

In silico studies were conducted using AutoDockTools software for ligand-protein docking. The docking scores were compared to the parent pipemidic acid docked to Bacterial DNA (deoxyribonucleic acid) gyrase and GABA (gamma-Aminobutyric acid) receptor from the PDB (Protein Data Bank) database. Sites of metabolism, biological activity, quantum chemical descriptors, and ADME (absorption, distribution, metabolism, and excretion) property predictions for each designed ligand were also evaluated.

Results:

The docking studies and biological activity predictions showed good anti-infective properties (ligand PAR03) whilst also suggesting a reduction in GABA receptor agonist activity. The performance of PAR03 correlates with its electronic properties showing electrophilic character (can generate Reactive Electrophilic Species (RES)).

Conclusion:

The results from this study indicate that modification of the piperazinyl region of pipemidic acid can be an effective way to improve the drug potency whilst also ensuring reduction of the associated side effects.