Synthesis of selected 5-thio-substituted tetrazole derivatives and evaluation of their antibacterial and antifungal activities

New Antifungal Agents with Azole Moieties

Fungal conditions affect a multitude of people worldwide, leading to increased hospitalization and mortality rates, and the need for novel antifungals is emerging with the rise of resistance and immunocompromised patients. Continuous use of azole drugs, which act by inhibiting the fungal CYP51, involved in the synthesis of ergosterol, essential to the fungal cell membrane, has enhanced the resistance and tolerance of some fungal strains to treatment, thereby limiting the arsenal of available drugs. The goal of this review is to gather literature information on new promising azole developments in clinical trials, with in vitro and in vivo results against fungal strains, and complementary assays, such as toxicity, susceptibility assays, docking studies, among others. Several molecules are reviewed as novel azole structures in clinical trials and with recent/imminent approvals, as well as other innovative molecules with promising antifungal activity. Structure-activity relationship (SAR) studies are displayed whenever possible. The azole moiety is brought over as a privileged structure, with multiple different compounds emerging with distinct pharmacophores and SAR. Particularly, 1,2,3-triazole natural product conjugates emerged in the last years, presenting promising antifungal activity and a broad spectrum against various fungi.

A Novel and Efficient Nano Alumina Based Cu (II) Catalyst for Three- Component Synthesis of 5-Substituted-1H-Tetrazoles

:

Tetrazoles as one of the most important synthetic heterocyclic compounds have so many applications in organic chemistry, the photographic industry, coordination chemistry, explosives and in particular, medicinal chemistry. Numerous methods have been reported in the literature for synthesis of tetrazoles, but much of them have some drawbacks including the use of strong Lewis acids or expensive and toxic metals and employment of acidic media. Azides may react with acids to yield toxic and flammable HN3 gas. Furthermore, many methods used high polar solvents such as DMF at high temperatures and very tedious work-up. Heterogeneous catalysts are preferred because of owing to easy handling, safety, recoverability and reusability. Catalyst separation and recycling is highly desirable because catalysts are often very expensive. On the other hand, in spite of higher reactivity and selectivity of homogeneous catalysts, the difficulty of separating them from the reaction medium can lead to the problem of reusing the catalyst. Also, most homogeneous catalysts are thermally unstable. To benefit advantages of both types of catalysts, one solution is using nanoparticles. Their higher surface area is the advantages of nanoparticles, which allows them to enhance the reaction rate. Many commercially important catalysts include active nanoparticles spread on high area oxide supports. Such catalysts are highly complex materials that are optimized to work for plenty of turnovers at high reaction rates and with high selectivity. Aldehyde (1 mmol), hydroxylamine hydrochloride (0.10 mg, 1.5 mmol), sodium azide (0.10 g, 1.5 mmol), distilled water (5 mL) and nano Al2O3@PCH-Cu (II) (0.01g, 1.04% mol) were added to round bottom flask (25 mL) and stirred at room temperature. After the completion of the reaction, water (10 mL) was added into reaction mixture and filtered. Excess sodium azide and hydroxylamine hydrochloride are dissolved in water and the catalyst remains on the filter. Extraction of product with diethyl ether (3×10 mL) and then evaporation of ether afforded the product. The product was recrystallized using hot ethanol to obtain pure product. We synthesized a novel, stable, highly reactive and efficient nano-sized heterogeneous catalyst (nano Al2O3@PCH-Cu (II)). We characterized it by FT-IR, ICP, SEM, TGA and EDX analysis. This catalyst was used for the efficient one-pot three-component synthesis of 5-substituted-1H-tetrazoles. An one-pot three-component synthesis of 5-substituted-1Htetrazoles is conducted, a reaction between various benzaldehydes, hydroxyl amine hydrochloride and sodium azide in the presence of a novel and highly efficient nano alumina supported poly(carboxylic acid hydrazide) Cu(II) complex, nano Al2O3@PCH-Cu(II), as heterogeneous catalyst in H2O at room temperature. This method has very mild reaction conditions as well as the advantages of easy separation and reusability of the catalyst, very short reaction times, high yields and using H2O as green solvent. Furthermore, using this method very high TON and TOF values obtained for all isolated products.

Design, Synthesis, and Functional Evaluation of 1, 5-Disubstituted Tetrazoles as Monoamine Neurotransmitter Reuptake Inhibitors

Tetrazoles were designed and synthesized as potential inhibitors of triple monoamine neurotransmitters (dopamine, norepinephrine, serotonin) reuptake based on the functional and docking simulation of compound 6 which were performed in a previous study. The compound structure consisted of a tetrazole-linker (n)-piperidine/piperazine-spacer (m)-phenyl ring, with tetrazole attached to two phenyl rings (R1 and R2). Altering the carbon number in the linker (n) from 3 to 4 and in the spacer (m) from 0 to 1 increased the potency of serotonin reuptake inhibition. Depending on the nature of piperidine/piperazine, the substituents at R1 and R2 exerted various effects in determining their inhibitory effects on monoamine reuptake. Docking study showed that the selectivity of tetrazole for different transporters was determined based on multiple interactions with various residues on transporters, including hydrophobic residues on transmembrane domains 1, 3, 6, and 8. Co-expression of dopamine transporter, which lowers dopamine concentration in the biophase by uptaking dopamine into the cells, inhibited the dopamine-induced endoctytosis of dopamine D₂ receptor. When tested for compound 40 and 56, compound 40 which has more potent inhibitory activity on dopamine reuptake more strongly disinhibited the inhibitory activity of dopamine transporter on the endocytosis of dopamine D₂ receptor. Overall, we identified candidate inhibitors of triple monoamine neurotransmitter reuptake and provided a theoretical background for identifying such neurotransmitter modifiers for developing novel therapeutic agents of various neuropsychiatric disorders.

Novel tetrazole and cyanamide derivatives as inhibitors of cyclooxygenase-2 enzyme: design, synthesis, anti-inflammatory evaluation, ulcerogenic liability and docking study

Nineteen new compounds containing tetrazole and/or cyanamide moiety have been designed and synthesised. Their structures were confirmed using spectroscopic methods and elemental analyses. Anti-inflammatory activity for all the synthesised compounds was evaluated in vivo. The most active compounds 4c, 5a, 5d-f, 8a and b and 9a and b were further investigated for their ulcerogenic liability and analgesic activity. Pyrazoline derivatives 9b and 8b bearing trimethoxyphenyl part and SO₂NH₂ or SO₂Me pharmacophore showed equal or nearly the same ulcerogenic liability (UI: 0.5, 0.75, respectively), to celecoxib (UI: 0.50). Most of tested compounds showed potent central and/or peripheral analgesic activities. Histopathological investigations were done to evaluate test compounds effect on rat's gastric tissue. The obtained results were in consistent with the in vitro data on COX evaluation. Docking study was also done for all the target compounds inside COX-2-active site.

N-[3-Methyl-1-phenyl-1-(1H-tetrazol-1-yl)butan-2-yl]acetamide

In the molecule of the title compound, C14H19N5O, the dihedral angle formed between the tetrazole and phenyl rings is 68.39 (4)°. In the crystal, molecules are linked by N—H...N, C—H...N and C—H...O hydrogen bonds to form two-dimensional networks extending parallel to thebcplane.

Tetrazolium compounds: synthesis and applications in medicine

Tetrazoles represent a class of five-membered heterocyclic compounds with polynitrogen electron-rich planar structural features. This special structure makes tetrazole derivatives useful drugs, explosives, and other functional materials with a wide range of applications in many fields of medicine, agriculture, material science, etc. Based on our research works on azoles and other references in recent years, this review covers reported work on the synthesis and biological activities of tetrazole derivatives.

Investigation of Ugi-4CC derived 1H-tetrazol-5-yl-(aryl) methyl piperazinyl-6-fluoro-4-oxo-1,4-dihydroquinoline-3-carboxylic acid: synthesis, biology and 3D-QSAR analysis

Novel series of 7-piperazinylquinolones with tetrazole derivatives were synthesized and evaluated for their antibacterial activity against various strains of Staphylococcus aureus. All the synthesized compounds showed significant in vitro antibacterial activity against Gram-positive bacteria whereas some compounds displayed moderate activity against Gram-negative bacteria. Among all the synthesized compounds, compounds (6a-c, 6e-g, 6i-k, 6m, 6'f and 6'm) were found to be more effective with MIC ranging from (0.78-3.12 μg/mL) against S. aureus (ATCC-29213) than the control; ciprofloxacin (MIC = 25 μg/mL). Moreover, these analogues displayed no toxicity up to MIC = 0.39 μg/mL against mammalian cell line L-929. Furthermore, to correlate the biological activities of synthesized compounds with their 3D conformation, we attempted 3D-QSAR study.

A convenient eco-friendly system for the synthesis of 5-sulfenyl tetrazole derivatives of indoles and pyrroles employing CeCl3·7H2O in PEG-400

The use of CeCl₃·7H₂O in PEG-400 for the convenient synthesis of 5-sulfenyl tetrazoles derived from indoles and pyrroles, is reported. The scope and limitations of the transformation were also studied.

Design, synthesis, and evaluations of antifungal activity of novel phenyl(2H-tetrazol-5-yl)methanamine derivatives

Fungal infections pose a continuous and serious threat to human health and life. The intrinsic resistance has been observed in many genera of fungi. Many fungal infections are caused by opportunistic pathogens that may be endogenous (Candida infections) or acquired from the environment (Cryptococcus and Aspergillus infections). So, new therapeutic strategies are needed to combat various fungal infections. Fluconazole shows good antifungal activity with relatively low toxicity and is preferred as first line antifungal therapy, but it has suffered from severe drug resistance. So, there is a need to design novel analogues by modification of fluconazole-like structure. A novel series of phenyl(2H-tetrazol-5-yl)methanamine derivatives were synthesized by reaction of α-amino nitrile with sodium azide and ZnCl2 in presence of isopropyl alcohol. They were evaluated for antifungal activity against Candida albicans and Aspergillus niger and subjected to docking study against 1EA1.

A simple and safe method for the preparation of bis[2-(2H-tetrazol-5-yl)pyridinium] tetrachloridozincate(II)

In the title complex salt, (C6H6N5)2[ZnCl4], the Zn(II) cation is coordinated by four chloride ligands in a distorted tetrahedral geometry. The organic cations and complex anions are connected by N-H···Cl hydrogen bonds, leading to the formation of a three-dimensional network. The title complex salt was synthesized by the reaction of sodium azide, pyridine-2-carbonitrile and ZnCl2 in aqueous solution. The salt was characterized by elemental analysis and IR and UV-Vis spectroscopy.

Synthesis, anticandidal activity and cytotoxicity of some tetrazole derivatives

In this study, 14 different 2-[(1-methyl-1H-tetrazole-5-yl)thio]-1-(phenyl)ethanone derivatives (1-14) were synthesized. The structures of the obtained compounds were elucidated using IR, (1)H-NMR, (13)C-NMR and FAB(+)-MS spectral data and elemental analyses results. The compounds were screened for their anticandidal activity using the microbroth dilution method and for their cytotoxic effects using the MTT assay against NIH/3T3 cells. Some of the compounds were found to be potent anticandidal agents with weak cytotoxicities.