Synthesis of some new pyrazolo[1,5-a]pyrimidine, pyrazolo[5,1-c]triazine, 1,3,4-thiadiazole and pyridine derivatives containing 1,2,3-triazole moiety

ZIKV Inhibitors Based on Pyrazolo[3,4-d]pyridazine-7-one Core: Rational Design, In Vitro Evaluation, and Theoretical Studies

The Zika virus (ZIKV) is believed to cause birth defects, and no anti-ZIKV drugs have been approved by medical organizations to date. Starting from antimicrobial lead compounds with a pyrazolo[3,4-d]pyridazine-7-one scaffold, we synthesized 16 derivatives and screened their ability to interfere with ZIKV infection utilizing a cell-based phenotypic assay. Of these, five compounds showed significant inhibition of ZIKV with a selective index value greater than 4.6. In particular, compound 9b showed the best anti-ZIKV activity with a selectivity index of 22.4 (half-maximal effective concentration = 25.6 μM and 50% cytotoxic concentration = 572.4 μM). Through the brine shrimp lethality bioassay, 9b, 10b, 12, 17a, and 19a showed median lethal dose values in a range of 87.2-100.3 μg/mL. Compound 9b was also targeted to the NS2B-NS3 protease of ZIKV using molecular docking protocols, in which it acted as a noncompetitive inhibitor and strongly bound to five key amino acids (His51, Asp75, Ser135, Ala132, Tyr161). Utilizing the pharmacophore model of 9b, the top 20 hits were identified as prospective inhibitors of NS2B-NS3 protease, and six of them were confirmed for their stability with the protease via redocking and molecular dynamics simulations.

Pyrazolotriazines: Biological activities, synthetic strategies and recent developments

Heterocyclic compounds create an important class of molecules that demonstrates various chemical spaces for the definition of effective medicines. Many N-heterocycles display numerous biological activities. Among condensed heterocycles, pyrazolotriazine derivatives have received the attention of researchers owing to the extensive spectrum of biological activities. The reactivity of identified compounds was similar to the free azoles and triazines. The pyrazolotriazine scaffold exhibited antiasthma, antiinflammatory, anticancer, antithrombogenic activity and showed activity for major depression and pathological anxiety. Pyrazolotriazine derivatives also exhibited antibacterial, anticancer, antimetabolites, antidiabetic, antiamoebic, anticonvulsant, antiproliferative activity, human carbonic anhydrase inhibition, cyclin-dependent kinase 2 inhibition, tyrosinase and urease inhibition, MAO-B inhibition, TTK inhibition, thymidine phosphorylase inhibition, tubulin polymerization inhibition, protoporphyrinogen oxidase inhibition, GABA_A agonistic activity, hCRF1 receptor antagonistic activity, and CGRP receptor antagonistic activity. This paper structurally categorized various pyrazolotriazines to isomeric classes into six groups that containing pyrazolo [1,5-d] [1,2,4] triazine, pyrazolo [5,1-c] [1,2,4] triazine, pyrazolo [3,4-e] [1,2,4] triazine, pyrazolo [4,3-e] [1,2,4] triazines, pyrazolo [1,5-a] [1,3,5] triazine, and pyrazolo [3,4-d] [1,2,3] triazine and expressed biological activity, the synthetic procedures for each class of pyrazolotriazines, structure-activity relationship and their mechanism of action. Generally, this review summarily indicated the past and present studies about the discovery of new lead compounds with good biological activity.

New pyrazolopyrimidine derivatives with anticancer activity: Design, synthesis, PIM-1 inhibition, molecular docking study and molecular dynamics

In this study, new pyrazolopyrimidine derivatives were designed and evaluated for anticancer activity. PIM-1 inhibitiory activity were measured for the most potent compounds. Molecular docking study and molecular dynamics were also done. Thus, the novel derivatives of pyrazolo[1,5-a]pyrimidine have been synthesized and characterized using different spectroscopic techniques. HMBC and NOESY experiments were used to confirm regiospecific structure of pyrimidine ring. The newly synthesized derivatives were evaluated for their antitumor activities against HCT-116 and MCF-7 cell lines. These derivatives showed clear in vitro antitumor activities. Compound 5h showed the highest bioactivity (IC₅₀ = 1.51 µM) against HCT-116 cell line. While, compound 6c was the most potent derivative, its IC₅₀ was 7.68 µM against MCF-7 cell line. Compounds 5c, 5g, 5h, 6a and 6c showed PIM-1 inhibitory activity with IC₅₀ of 1.26, 0.95, 0.60, 1.82, 0.67, respectively µM that could be correlated with their cytotoxic effect. Molecular docking study was done to predict the mode of binding of the target compounds inside PIM-1 active site. The molecular dynamic simulation was conducted in order to evaluate stability of binding of the tested compounds.

Utility of 5-(furan-2-yl)-3-(p-tolyl)-4,5-dihydro-1H-pyrazole-1-carbothioamide in the synthesis of heterocyclic compounds with antimicrobial activity

Background

Pyrazolines show different biological activities. In recent years, interest in the chemistry of hydrazonoyl halides has been renewed. 1,3,4-Thiadiazoles are one of the most common heterocyclic pharmacophores with a wide range of biological activities.

Results

Ethyl 2-(5-(furan-2-yl)-3-(p-tolyl)-4,5-dihydro-1H-pyrazol-1-yl)-4-methyl-thiazole-5-carboxylate, 2-(5-(furan-2-yl)-3-(p-tolyl)-4,5-dihydro-1H-pyrazol-1-yl)thiazol-4(5H)-one, and 1-(2-(5-(furan-2-yl)-3-(p-tolyl)-4,5-dihydro-1H-pyrazol-1-yl)-4-methylthiazol-5-yl)ethan-1-one were synthesized from the reaction of 5-(furan-2-yl)-3-(p-tolyl)-4,5-dihydro-1H-pyrazole-1-carbothioamide with different halogenated compounds. Thiazole, 1,3,4-thiadiazole and pyrano[2,3-d]thiazole derivatives were also synthesized. The structures of the newly synthesized compounds were elucidated based on elemental analysis, spectral data, and alternative synthetic routes whenever possible. Additionally, the newly synthesized compounds were screened for antimicrobial activity against various microorganisms.

Conclusions

A new series of novel functionalized 1,3,4-thiadiazoles, 1,3-thiazoles, and pyrazoline-containing moieties were synthesized using hydrazonoyl halides as precursors and evaluated for their in vitro antibacterial, and antifungal activities. The antimicrobial results of the examined compounds revealed promising results and some derivatives have activities similar to the references used.

Electronic supplementary material

The online version of this article (10.1186/s13065-019-0566-y) contains supplementary material, which is available to authorized users.