Synthesis, characterization, biological evaluation and molecular docking of steroidal spirothiazolidinones

Syntheses and medicinal chemistry of spiro heterocyclic steroids

There is compelling evidence that incorporating a heterocyclic moiety into a steroid can alter its pharmacological and pharmacokinetic properties, driving intense interest in the synthesis of such hybrids among research groups. In this review, we present an overview of recent synthetic methodologies, spanning the period from 2000 to 2023, for the preparation of spiro heterocyclic steroids. The compounds surveyed encompass four-, five-, six-, and seven-membered heterocycles appended to various positions of steroidal backbones, with spirocycles containing oxygen, nitrogen, and sulfur atoms being predominant. The outlined synthetic procedures emphasize the pivotal steps for constructing the heterocycles, often accompanied by a detailed account of the overall synthesis pathway. The review encompasses innovative compounds, including bis-steroids linked by a spiro heterocycle and steroids conjugated to heterocyclic moieties containing three or more (hetero)cycles. Moreover, many compounds are accompanied by data on their biological activities, such as antiproliferative, antimalarial, antimicrobial, antifungal, steroid antagonist, and enzyme inhibition, among others, aimed at furnishing pertinent insights for the future design of more potent and selective drugs.

Inhibition of protein misfolding and aggregation by steroidal quinoxalin-2(1H)-one and their molecular docking studies

A series of D-ring fused 16-substituted steroidal quinoxalin-2(1H)-one attached to an electron-releasing (ER) or electron-withdrawing (EW) groups via steroidal oxoacetate intermediate were synthesized to investigate their protein aggregation inhibition potential using human lysozyme (HLZ). The influence of the type of substituent at the C-6 positions of the quinoxalin-2(1H)-one ring on the protein aggregation inhibition potential was observed, showing that the EW moiety improved the protein aggregation inhibition potency. Of all the evaluated compounds, NO2-substituted quinoxalin-2(1H)-one derivative 13 was the most active compound and had a maximum protein aggregation inhibition effect. Significant stabilization effects strongly support the binding of the most biologically active steroidal quinoxalin-2(1H)-one with docking studies. The predicted physicochemical and ADME properties lie within a drug-like space which shows no violation of Lipinski's rule of five except compounds 12 and 13. Combined, our results suggest that D-ring fused 16-substituted steroidal quinoxalin-2(1H)-one has the potential to modulate the protein aggregation inhibition effect.

Synthesis of steroidal dihydropyrazole derivatives using green ZnO NPs and evaluation of their anticancer and antioxidant activity

Zinc oxide nanoparticles (ZnO NPs) were synthesized by a green method using Azadirachta indica leaf extract. The structure of the prepared ZnO (NPs) were characterized by FT-IR, XRD, SEM-EDX and TEM analyses. The biosynthesized ZnO (NPs) were then used as a catalyst for the synthesis of steroidal dihydropyrazole derivatives through a one-pot multicomponent reaction involving phenyl acetylene and hydrazine derivatives. The anticancer activity of newly synthesized compounds were evaluated against three cancer cell lines namely HeLa (human cervical carcinoma), Hep3B (human hepatocellular carcinoma) and MCF7 (human breast adenocarcinoma) by MTT assay. The tested compounds were found to be active against all cancer cell lines and less toxic towards normal peripheral blood mononuclear cells (PBMCs). Antioxidant activity have also been investigated via free radical scavenging ability using DPPH, FRAP and ABTS assay. The tested compounds were found to exhibit moderate to good antioxidant activity which increases with increase in the concentration of steroidal dihydropyrazoles. Among all the tested steroidal dihydropyrazoles, compound 17 is found to be most active.

Design and synthesis of novel Imidazo[2,1-b]thiazole derivatives as potent antiviral and antimycobacterial agents

A series of novel acyl-hydrazone (4a-d) and spirothiazolidinone (5a-d, 6a-d) derivatives of imidazo[2,1-b]thiazole were synthesized and evaluated for their antiviral and antimycobacterial activity. The antituberculosis activity was evaluated by using the Microplate Alamar Blue Assay and the antiviral activity was evaluated against diverse viruses in mammalian cell cultures. According to the biological activity studies of the compounds, 5a-c displayed hope promising antitubercular activity, 6d was found as potent for Coxsackie B4 virus, 5d was found as effective against Feline corona and Feline herpes viruses. Consequently, the obtained results displayed that, 5a-d and 6d present a leading structure for future drug development due to its straightforward synthesis and relevant bioactivity.

Steroidal thiazolidinone derivatives: Design, synthesis and their molecular interaction with human serum albumin

A series of steroidal thiazolidinone derivatives have been synthesized through one-pot multicomponent reaction involving steroidal ketone, thiosemicarbazide/methyl-thiosemicarbazide and DMAD in presence of AlCl₃ as a Lewis acid catalyst. Among all the synthesized steroidal thiazolidinone derivatives, compound 7-9 (ST 7-9) were investigated for their in vitro molecular interaction with human serum albumin. Intrinsic fluorescence spectroscopy, constant wavelength synchronous fluorescence spectroscopy, circular dichroism and UV-visible absorption techniques have been exploited to characterize the binding phenomena in phosphate buffer solution at pH 7.4. The experimental results indicated that ST 7-9 bind to HSA and the intrinsic fluorescence of HSA was quenched through static quenching mechanism. The binding parameters were calculated and the binding constants obtained were 1.44 × 10⁵ M^-1 for ST 7, 0.84 × 10⁵ M^-1 for ST 8 and 1.06 × 10⁵ M^-1 for ST 9. Circular dichroism analysis confirms that the presence of ST 7-9, altered the secondary structure of HSA due to partial unfolding of the polypeptide chain. Furthermore, hemolytic activity assay demonstrated that the synthesized steroidal thiazolidinone derivatives have good compatibility towards human red blood cells. Finally, molecular docking studies revealed that the steroidal thiazolidinones can bind in the hydrophobic cavity of HSA, by hydrophobic and hydrogen bonding interaction. These results provided valuable information about the binding mechanism of ST 7-9 with HSA and play a pivotal role in the development of steroidal heterocycle inspired compounds.

Facile one-pot multicomponent synthesis and molecular docking studies of steroidal oxazole/thiazole derivatives with effective antimicrobial, antibiofilm and hemolytic properties

A series of steroidal oxazole and thiazole derivatives have been synthesized employing thiosemicarbazide/semicarbazide hydrochloride and ethyl 2-chloroacetoacetate with a simple and facile one-pot multicomponent reaction pathway. The antimicrobial activity of newly synthesized compounds were evaluated against four bacterial strains namely Gram-negative (Escherichia coliand Pseudomonas aeruginosa) and Gram-positive bacteria (Staphylococcus aureus and Listeria monocytogenes) in addition to pathogenic fungi (Candida albicans and Cryptococcus neoformans). Bioactivity assay manifested that most of the compounds exhibited good antimicrobial activity. To provide additional insight into antimicrobial activity, the compounds were also tested for their antibiofilm activity against S. aureus biofilm. Moreover, molecular docking study shows binding of compounds with amino acid residues of DNA gyrase and glucosamine-6-phosphate synthase (promising antimicrobial target) through hydrogen bonding interactions. Hemolytic activity have been also investigated to ascertain the effect of compounds over RBC lysis and results indicate good prospects for biocompatibility. The expedient synthesis of steroidal heterocycles, effective antibacterial and antifungal behavior against various clinically relevant human pathogens, promising biocompatibility offer opportunities for further modification and potential applications as therapeutic agents.

Microwave-assisted MgO NP catalyzed one-pot multicomponent synthesis of polysubstituted steroidal pyridines

MgO NPs were proved to be a highly efficient catalyst for mild and clean conversion of steroids to steroidal heterocycles.

Silica-supported NiO nanocomposites prepared via a sol–gel technique and their excellent catalytic performance for one-pot multicomponent synthesis of benzodiazepine derivatives under microwave irradiation

Heterogeneous and versatile NiO–SiO₂ NCs were synthesized by a sol–gel technique and used as a catalyst for the one-pot multicomponent synthesis of benzodiazepines.

Synthesis and characterization of steroidal heterocyclic compounds, DNA condensation and molecular docking studies and their in vitro anticancer and acetylcholinesterase inhibition activities

A facile and efficient approach for the synthesis of steroidal heterocyclic compounds (4–12) has been performed. Furthermore, these newly synthesized compounds were evaluated for their various biological activities.