Novel Synthesis of Fluorinated Cyanoketene N,S-Acetals and Their Conversions to Fluorinated Pyrazole Derivatives

Purine analogs: synthesis, evaluation and molecular dynamics of pyrazolopyrimidines based benzothiazole as anticancer and antimicrobial CDK inhibitors

Cyclin dependent kinases (CDKs) enzymes regulate cell proliferation and transcriptional processes and can be considered as important targets for the development of anticancer and antimicrobial drugs. In this work, novel benzothiazolyl pyrazolopyrimidine carboxamide and benzothiazolyl pyrazolopyrimidine carbonitrile derivatives were synthesized and characterized. The synthetic process was carried out via the reaction of ylidine benzothiazole derivatives with pyrazolocarboxamide and pyrazolocarbonitrile through a Michael addition pathway. Docking studies were done against CDK2 and CDK9 enzymes and revealed that compound 8a showed high free energy of binding against CDK2 (-8.10 kcal/mol) while compound 15a showed the highest free energy of binding against CDK2 (-8.16 kcal/mol) and CDK9 (-7.87 kcal/mol). Molecular dynamics simulations were conducted to compare the stability of binding of the most active compound 15a and the potent reference drugs roscovitine and dinaciclib. A CDK enzyme assay was done against CDK2 and CDK9 for the previously mentioned top-ranked compounds, 8a and 15a. It was found that compound 15a was the most potent inhibitor for both enzymes with IC₅₀ of 127 ± 1.01 nM and 65 ± 0.50 nM. The anticancer activity of the synthesized compounds was also determined by NCI against 60 cell lines. Compound 8a showed the highest cytotoxic activity against a large number of the tested cell lines. The antimicrobial activity of the synthesized compounds was determined against various gram positive and gram-negative bacteria as well as fungi. The results showed that compound 15a had the strongest antibacterial activity.

Purine analogues as potential CDK9 inhibitors: New pyrazolopyrimidines as anti-avian influenza virus

Cyclin dependent kinases (CDKs) are a group of enzymes involved in different phases of the cell cycle. In addition, it has been reported that CDK9 could be used as a crucial target for the development of antiviral drugs such as purine analogues; roscovitine and dinaciclib. A new series of benzothiazolyl pyrazolopyrimidine carboxamide derivatives were synthesized and evaluated for their antiviral activity against avian influenza "bird flu" (H5N1). The novel compounds were synthesized via the reaction of pyrazolo carboxamide derivatives with different derivatives of ylidine benzothiazole. The reaction proceeded via a Michael addition pathway. Antiviral activity was determined using a plaque reduction assay against the H5N1 virus. Five compounds showed the highest inhibitory activity in the range of 61.6 to 71.6% at 0.1 μmol/mL. Based on a molecular docking study, an enzyme assay was carried out against CDK9 for the previously mentioned top-ranked compounds. It was found that compound 11f was the most potent inhibitor of CDK9 with an IC₅₀ of 0.062 μmol/mL. A QSAR model was built to determine the hidden feature responsible for the biological activity of the novel compounds. It was found that two sets of descriptors, 3 D Potential energy descriptors and 2 D Atom Counts and Bond Counts descriptors, were correlated to a linear model with RMSE and r2 coefficient values of 0.75 and 0.80, respectively. A molecular dynamic simulations study of 11f over 10 ns against dinaciclib showed that both 11f and dinaciclib achieved equilibrium at 2 Å.Supplemental data for this article is available online at https://doi.org/10.1080/15257770.2022.2059674 .

Enantioselective Chromatographic Separation and Lipase Catalyzed Asymmetric Resolution of Biologically Important Chiral Amines

Cyanoacetamides are vital synthons in synthetic organic chemistry. However, methods to enantiopure cyanoacetamides have not yet been well explored. In this work, the preparation of cyanoacetamide synthons RS-(1a–4a) or methoxyacetamides RS-(1b–4b) in enantiopure/enriched form was investigated. Compounds S-1, S-2, R-1b, R-1a, andR-2b were prepared in enantiopure form (ee > 99%) while compounds S-4, R-2a, and R-4a were achieved in ee 9%, 80%, and 76%, respectively. Many baselines enantioselective HPLC separations of amines 1–4, their cyanoacetamides (1a–4a), and methoxyacetamides (1b–4b) were achieved by utilizing diverse mobile-phase compositions and two cellulose-based CSPs (ODH® and LUX-3® columns). Such enantioselective HPLC separations were used to monitor the lipase-catalyzed kinetic resolution of amines RS-(1–4).

New Route to the Synthesis of Benzamide-Based 5-Aminopyrazoles and Their Fused Heterocycles Showing Remarkable Antiavian Influenza Virus Activity

This study describes a new route to the synthesis of novel benzamide-based 5-aminopyrazoles and their corresponding pyrazolo[1,5-a]pyrimidine and pyrazolo[5,1-c][1,2,4]triazine derivatives. Benzamide-based 5-aminopyrazoles were prepared through a reaction of benzoyl isothiocyanate with malononitrile in KOH-EtOH followed by alkylation with alkyl halides and then a reaction with hydrazine. In an attempt to react benzoyl isothiocyanate with ethyl cyanoacetate in KOH-EtOH followed by alkylation with methyl iodide at room temperature and then a reaction with hydrazine has resulted in the formation of 3-ethoxy-5-phenyl-1H-1,2,4-triazole. The structures of the new compounds were characterized by mass spectroscopy, ¹H nuclear magnetic resonance (¹H NMR) spectroscopy, infrared spectroscopy (IR), and X-ray analysis. The new compounds were tested in vitro for their anti-influenza A virus (subtype H5N1) activity. Among the synthesized compounds, eight compounds 3b, 4, 10b, 10c, 12a, 19, 21a, and 21b were found to possess significant antiviral activities against bird flu influenza (H5N1) with viral reduction in the range of 85-65%.

Structure-based design, synthesis and biological evaluation of a newer series of pyrazolo[1,5-a]pyrimidine analogues as potential anti-tubercular agents

In-depth study of structure-based drug designing can provide vital leads for the development of novel, clinically active molecules. In this present study, twenty six novel pyrazolo[1,5-a]pyrimidine analogues (6a-6z) were designed using molecular docking studies. The designed molecules were synthesized in good yields. Structural elucidation of the synthesized molecules was carried out using IR, MS, ¹H NMR and ¹³C NMR spectroscopy. All the synthesized compounds were evaluated for their in-vitro anti-tubercular activity against H37Rv strain by Alamar Blue assay method. Most of the synthesized compounds displayed potent anti-tubercular activities. Amongst all the tested compounds 6p, 6g, 6n and 6h exhibited promising anti-tubercular activity. Further, these potent compounds were gauged for MDR-TB, XDR-TB and cytotoxic study. None of these compounds exhibited potent cytotoxicity. Stability of protein ligand complex was further evaluated by molecular dynamics simulation for 10 ns. All these results indicate that the synthesized compounds could be potential leads for further development of new potent anti-tubercular agents.

Asymmetric additions of thioglycolates and N-Boc aldimines catalyzed by a bifunctional tertiary-amine squaramide

A highly enantioselective asymmetric addition reaction of thioglycolates and N-Boc aldimines was promoted by a bifunctional tertiary-amine squaramide catalyst.

Sc(OTf)3-mediated 1,3-dipolar cycloaddition-ring cleavage-rearrangement: a highly stereoselective access to Z-β-enaminonitriles

A novel and highly stereoselective synthesis of Z-β-enaminonitriles from azides and α,β-unsaturated nitriles is reported. The reaction proceeds via a 1,3-dipolar cycloaddition-ring cleavage-rearrangement cascade mediated by a catalytic amount of Sc(OTf)3. A plausible reaction mechanism for this process is depicted.