Synthesis and anti-HSV-1 activity of new 1,2,3-triazole derivatives

Antivenom effects of 1,2,3-triazoles against Bothrops jararaca and Lachesis muta snakes

Snake venoms are complex mixtures of proteins of both enzymes and nonenzymes, which are responsible for producing several biological effects. Human envenomation by snake bites particularly those of the viperid family induces a complex pathophysiological picture characterized by spectacular changes in hemostasis and frequently hemorrhage is also seen. The present work reports the ability of six of a series of 1,2,3-triazole derivatives to inhibit some pharmacological effects caused by the venoms of Bothrops jararaca and Lachesis muta. In vitro assays showed that these compounds were impaired in a concentration-dependent manner, the fibrinogen or plasma clotting, hemolysis, and proteolysis produced by both venoms. Moreover, these compounds inhibited biological effects in vivo as well. Mice treated with these compounds were fully protected from hemorrhagic lesions caused by such venoms. But, only the B. jararaca edema-inducing activity was neutralized by the triazoles. So the inhibitory effect of triazoles derivatives against some in vitro and in vivo biological assays of snake venoms points to promising aspects that may indicate them as molecular models to improve the production of effective antivenom or to complement antivenom neutralization, especially the local pathological effects, which are partially neutralized by antivenoms.

5-Methyl-N′-[(3Z)-2-oxo-2,3-dihydro-1H-indol-3-ylidene]-1-phenyl-1H-1,2,3-triazole-4-carbohydrazide

In the title compound, C₁₈H₁₄N₆O₂, the benzene ring is slightly twisted out of the plane of the 1,2,3-triazole ring (r.m.s. deviation = 0.010 Å), forming a dihedral angle of 6.20 (13)°. The nine non-H ring atoms of the fused five- and six-membered ring system are almost coplanar (r.m.s. deviation = 0.032 Å). The near coplanarity in the central residue is consolidated by an intra­molecular bifurcated N—H⋯(O,N) hydrogen bond. The conformation about the N=C bond is Z. In the crystal, supra­molecular chains along [101] are sustained by N—H⋯O hydrogen bonds and C—H⋯O inter­actions. These are consolidated into a three-dimensional architecture by C—H⋯π and π–π inter­actions; the latter occur between centrosymmetrically related 1,2,3-triazole rings [centroid–centroid distance = 3.6056 (14) Å].

A Facile Eco-Friendly One-Pot Five-Component Synthesis of Novel 1,2,3-Triazole-Linked Pentasubstituted 1,4-Dihydropyridines and their Biological and Photophysical Studies

An eco-friendly one-pot five-component synthesis of novel 1,2,3-triazole-linked pentasubstituted 1,4-dihydropyridines under ultrasonic and microwave irradiation in polyethylene glycol (PEG) 400 is described. All newly synthesised compounds were evaluated for antibacterial activity, antifungal activity, antioxidant activity, and photophysical properties. Antimicrobial activity was evaluated against six microbial strains. All compounds exhibited antifungal activity against Aspergillus niger and Aspergillus flavus and moderate antibacterial activity against Gram positive bacteria (Staphylococcus aureus and Bacillus subtilis). Antioxidant activity was evaluated using a 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay. All compounds showed good to moderate antioxidant activity. Furthermore all new compounds showed strong fluorescence in solution.

Design and synthesis of new 4-pyrazolin-3-yl-1,2,3-triazoles and 1,2,3-triazol-4-yl-pyrazolin-1-ylthiazoles as potential antimicrobial agents

New pyrazolyl-1,2,3-triazoles and 1,2,3-triazol-4-yl-pyrazolylthiazoles were synthesized through multi step reactions using 1-tolylyl-4-acetyl-5-methyl-1,2,3-triazole as a precursor. All the newly synthesized compounds were characterized by spectral and elemental analyses. The structure of 11b was evidenced by X-ray crystallographic study. The newly synthesized compounds were evaluated for their antimicrobial activities and also their minimum inhibitory concentration (MIC) against most of test organisms was performed. Amongst the tested compounds 5a, 5c, 11b and 11c displayed excellent antimicrobial activity.

Synthesis and anti-HSV-1 evaluation of new 3H-benzo[b]pyrazolo[3,4-h]-1,6-naphthyridines and 3H-pyrido[2,3-b]pyrazolo[3,4-h]-1,6-naphthyridines

BACKGROUND

Herpes simplex virus type-1 (HSV-1) is the primary cause of facial lesions (mouth, lips, and eyes) in humans. The widespread use of acyclovir and nucleoside analogues has led to emergence of HSV strains that are resistant to these drugs. Recently, non-nucleoside anti-HSV compounds have received considerable attention. 1,6-Naphthyridines are a class of heterocyclic compounds that exhibit a broad spectrum of biological activities such as inhibitor of HIV-1 integrase, HCMV, FGF receptor-1 tyrosine kinase, and the enzyme acetylcholinesterase. We previously reported the synthesis, SAR studies, and evaluation anti-HSV-1 activity of 3H-benzo[b]pyrazolo[3,4-h]-1,6-naphthyridines. In the course of our search for new 1,6-naphthyridines derivatives with potential activity against HSV-1, we have synthesized and evaluated new 3H-benzo[b]pyrazolo[3,4-h]-1,6-naphthyridines (1a-k) and 3H-pyrido[2,3-b]pyrazolo[3,4-h]-1,6-naphthyridines (2a-c).

RESULTS

A known synthetic approach was used for preparing new 3H-benzo[b]pyrazolo[3,4-h]-1,6-naphthyridines (1a-k) and 3H-pyrido[2,3-b]pyrazolo[3,4-h]-1,6-naphthyridines (2a-c), starting from ethyl 4-chloro-1-phenyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylate (7). All compounds were identified by FTIR, 1H NMR, and mass spectrometry. The antiviral effect on HSV-1 virus replication was determined.

CONCLUSIONS

The compounds 1d, 1f, 1g, and 1h exhibited the highest anti-HSV-1 activity. In general, 3H-benzo[b]pyrazolo[3,4-h]-1,6-naphthyridines were more effective inhibitors than their corresponding 3H-pyrido[2,3-b]pyrazolo[3,4-h]-1,6-naphthyridines. The compound 1h reduced the virus yield in 91% at 50 μM and exhibited a low cytotoxicity (CC50 600 μM).