Three-Component Synthesis of 1-Substituted 5-Aminotetrazoles Promoted by Bismuth Nitrate.

A nontoxic bismuth-promoted multicomponent synthesis of 5-aminotetrazoles and bistetrazoles is reported. The reaction of phenyl isothiocyanate, NaN3, and amine (primary aliphatic, aromatic, and aliphatic diamine) promoted by Bi(NO3)3·5H2O under microwave heating affords good yields, short reaction times, simple workup, and purification without column chromatography. A set of diagnostic 1H NMR signals was identified as a guide for quickly elucidating the exclusive (or main) regioisomer formed, with the stronger electron donor group located at heterocyclic nitrogen 1. This regioselectivity is strongly dependent on the electronic density of the amine. It is opposite to that obtained by several thiourea desulfurization methods promoted by thiophilic metals and metal-free protocols.

Microwave extraction and molecular imprinted polymer isolation of bergenin applied to the dendrochronological chemical study of Peltophorum dubium.

This study describes methodologies for extracting and isolating bergenin, a C-glucoside of 4-O-methylgallic acid found in some plants and it presents various in vitro and in vivo biological activities. Bergenin was previously obtained from the Pelthophorum dubim (Fabaceae) roots with a good yield. Conventional chromatographic procedures of the CHCl3 soluble fraction of the MeOH extract gave 3.62% of this glucoside. An HPLC/DAD method was also developed and validated for bergenin and its precursor, gallic acid quantifications. Microwave extractions with different solvents were tested to optimize the extraction of bergenin, varying the temperature and time. MAE (Microwave Assisted Extraction) was more efficient than conventional extraction procedures, giving a higher yield of bergenin per root mass (0.45% vs. 0.0839%). Molecularly imprinted polymer (MIP) and non-imprinted polymer (NIP) based on bergenin as the template molecule, methacrylic acid, and ethylene glycol dimethacrylate were synthesized and characterized by FTIR and SEM (Scanning Electron Microscopy). Bergenin adsorption experiments using MIP and NIP followed by molecular imprinted solid phase extraction (MISPE) showed that MIP had a higher selectivity for bergenin than NIP. A dendrochronological study using the proposed method for detection and quantification of gallic acid and bergenin in five P. dubium growth rings of a 31-year-old heartwood and in the phelloderm and barks indicated that bergenin was more abundant in the 11-14th growth rings of the heartwood and decreased from the heartwood to the barks.

Regioselectivity in the Nitration of Eugenol Is Independent of Inorganic Reagents: An Experimental and Theoretical Investigation with Synthetic and Mechanistic Implications.

In this study, we reinvestigated the straightforward nitration of eugenol using traditional reagents and bismuth nitrate. NMR analysis of the obtained products revealed that the regioselectivity of eugenol nitration was independent of the inorganic nitrating reagent used, consistently resulting in the formation of 6-nitroeugenol. This contradicts previous literature reports because the elusive synthesis of 5-nitroeugenol using Bi(NO3)3·5H2O was not achievable through straightforward methods; instead, this isomer could only be prepared via the well-established three-step synthesis. Theoretical investigations using DFT calculations, considering both the dielectric constant of the medium and explicit water molecules, substantiated this regioselectivity. It was found that hydration water played a critical role in the formation of a Zundel cation, shifting the thermodynamic equilibrium toward the exclusive production of 6-nitroeugenol. These results imply that all biological studies involving eugenol derivatives synthesized via direct nitration with Bi(NO3)3·5H2O should be reviewed, as they dealt with 6-substituted eugenol derivatives rather than the previously assumed 5-substituted eugenol.

In Situ Transesterification from Soybean Seed Using Mechanochemical Methods toward Producing Biodiesel.

The research and development of new routes of biodiesel synthesis have been increasingly in line with the principles of green chemistry. In this sense, mechanochemistry is a promising technique, able to ally the energetic potential with reductions in the use of solvents and steps of treatment of the sample and the purification of the product. To date, this is the first work using mechanochemistry directly in extracting soybean oil from its seed and the in situ transesterification reaction by applying a reactive soybean oil extraction process. The presence of n-hexane was studied in different molar proportions (relative to the oil content), and a low solvent consumption in a 3:1 ratio was adopted. Mechanochemistry favored oil diffusion in the n-hexane solvent, resulting in a mean triglyceride content equal to 90%, against 66% obtained in the tests without spheres in the planetary ball mill. The catalyst content was also evaluated, and 4% NaOH (weight, concerning the oil) was the concentration that presented less residue of nontransesterified glycerides in the samples for ethyl ester preparation. Additionally, the protein content was determined on the residual soybean cake, with no loss of nutritional potential when subjected to the mechanochemical process.

Proteomic Profiling of Paracoccidioides brasiliensis in Response to Phenacylideneoxindol Derivative: Unveiling Molecular Targets and Pathways.

BACKGROUND: The treatment of paracoccidioidomycosis (PCM) is a challenge, and the discovery of new antifungal compounds is crucial. The phenacylideneoxindoles exhibited promising antifungal activity against Paracoccidioides spp., but their mode of action remains unknown. METHODS: Through proteomic analysis, we investigated the effects of (E)-3-(2-oxo-2-phenylethylidene)indolin-2-one on P. brasiliensis. In addition, we investigated the metabolic alterations of P. brasiliensis in response to the compound. Furthermore, the effects of the compound on the membrane, ethanol production, and reactive oxygen species (ROS) production were verified. RESULTS: We identified differentially regulated proteins that revealed significant metabolic reorganization, including an increase in ethanol production, suggesting the activation of alcoholic fermentation and alterations in the rigidity of fungal cell membrane with an increase of the ergosterol content and formation of ROS. CONCLUSIONS: These findings enhance our understanding of the mode of action and response of P. brasiliensis to the investigated promising antifungal compound, emphasizing its potential as a candidate for the treatment of PCM.

An overview of New Psychoactive Substances (NPS) in northeast Brazil: NMR-based identification and analysis of ecstasy tablets by GC-MS.

The actual illicit market for synthetic drugs is characterized by a wide variety of psychoactive substances of different chemical and pharmacological classes, such as amphetamine-type stimulants and new psychoactive substances. The knowledge about its chemical composition, as well as the nature and quantity of the active substances present, is important for emergency care in intoxication cases by these substances and to establish adequate chemical and toxicological analysis procedures in forensic laboratories. The aim of this work was to study the prevalence of amphetamine-type stimulants and new psychoactive substances in the states of Bahia and Sergipe, in the northeast region of Brazil, involving samples of drugs seized by the local police forces from 2014 to 2019. In a total of 121 seized and analyzed samples, in which ecstasy tablets predominated (n = 101), nineteen substances were identified using GC-MS and 1D NMR techniques, comprising classical synthetic drugs and new psychoactive substances (NPS). In order to determine the composition of ecstasy tablets, an analytical method based on GC-MS was applied after validation. Analyzes of 101 ecstasy tablets showed that MDMA was the main substance, being found in 57% of the samples, in amounts between 27.3 and 187.1 mg per tablet. In addition, mixtures of MDMA, MDA, synthetic cathinones and caffeine were observed in 34 samples. These results demonstrate that the variety of substances found and the composition of seized materials in northeast Brazil is similar to other studies carried out previously in other Brazilian regions.

3-phenacylideneoxindoles as a new class of antifungal compounds against Paracoccidioides spp.

Aims: Considering the need to identify new compounds with antifungal action, the activity of five 3-phenacylideneoxindoles compounds was evaluated. Materials & methods: The compounds were synthesized, and their antifungal activity was elucidated through minimum inhibitory concentration tests and interaction assay with other antifungals. Potential targets of compounds were predicted in silico. Results: 3-phenacylideneoxindoles compounds inhibited fungal growth with minimum inhibitory concentration and minimum fungicidal concentration ranging from 3.05 to 12.26 µM. The compounds demonstrated high selectivity index and presented a synergistic effect with itraconazole. In silico prediction revealed the pentafunctional AROM polypeptide, enolase, superoxide dismutase, catalase and kinases as proteins targets of the compound 4a. Conclusion: The results demonstrate that 3-phenacylideneoxindoles is a potential new class of antifungal compounds for paracoccidioidomycosis treatment.

Patients affected by paracoccidioidomycosis (PCM) require long-term treatment, which commonly influences their adherence. In addition, only three drugs are in clinical use, which indicates the relevance of research in identifying new drugs for treating PCM. Thus, five drugs were tested in the laboratory to verify whether they could prevent the growth of the fungus without being toxic to humans. In addition, whether these compounds in combination with drugs used to treat PCM could be even more potent was evaluated. All compounds tested efficiently inhibited the growth of Paracoccidioides, the fungus that causes PCM. One drug was identified that, combined with itraconazole, decreased the required dose of both the discovered compound and itraconazole needed to inhibit fungal growth. Using computational tools, this work suggests how the new drug could act against the fungus. The results demonstrate a potential new treatment option, but more studies are needed to confirm the safety of these drugs.

Phenotypic and in silico studies for a series of synthetic thiosemicarbazones as New Delhi metallo-beta-lactamase carbapenemase inhibitors.

The past two decades have been marked by a global spread of bacterial resistance to ß-lactam drugs and carbapenems derivatives are the ultimate treatment against multidrug-resistant bacteria. ß-lactamase expression is related to resistance which demands the development of bacterial resistance blockers. Drug inhibitor combinations of serine-ß-lactamase and ß-lactam were successful employed in therapy despite their inactivity against New Delhi metallo-beta-lactamase (NDM). Until now, few compounds are active against NDM-producing bacteria and no specific inhibitors are available yet. The rational strategy for NDM inhibitors development starts with in vitro assays aiming to seek compounds that could act synergistically with ß-lactam antibiotics. Thus, eight thiosemicarbazone derivatives were synthesized and investigated for their ability to reverse the resistant phenotype in NDM in Enterobacter cloacae. Phenotypic screening indicated that four isatin-beta-thiosemicarbazones showed Fractional Inhibitory Concentration (FIC) ≤ 250 µM in the presence of meropenem (4 µg/mL). The most promising compound (FIC= 31.25 µM) also presented synergistic effect (FICI = 0.34). Docking and molecular dynamics studies on NDM-thiosemicarbazone complex suggested that 2,3-dihydro-1H-indol-2-one subunit interacts with catalytic zinc and interacted through hydrogen bonds with Asp124 acting like a carboxylic acid bioisostere. Additionally, thiosemicarbazone tautomer with oxidized sulfur (thione) seems to act as a spacer rather than zinc chelator, and the aromatic moieties are stabilized by pi-pi and cation-pi interactions with His189 and Lys221 residues. Our results addressed some thiosemicarbazone structural changes to increase its biological activity against NDM and highlight its scaffold as promising alternatives to treat bacterial resistance.Communicated by Ramaswamy H. Sarma.

Two New ßN-Alkanoyl-5-Hydroxytryptamides with Relevant Antinociceptive Activity.

In this work, we describe a new route for the synthesis and the antinociceptive effects of two new ßN-alkanoyl-5-hydroxytryptamides (named C20:0-5HT and C22:0-5HT). The antinociceptive activities were evaluated using well-known models of thermal-induced (reaction to a heated plate, the hot plate model) or chemical-induced (licking response to paw injection of formalin, capsaicin, or glutamate) nociception. The mechanism of action for C20:0-5HT and C22:0-5HT was evaluated using naloxone (opioid receptor antagonist, 1 mg/kg), atropine (muscarinic receptor antagonist, 1 mg/kg), AM251 (cannabinoid CB1 receptor antagonist, 1 mg/kg), or ondansetron (5-HT3 serotoninergic receptor antagonist, 0.5 mg/kg) 30 min prior to C20:0-5HT or C22:0-5HT. The substances both presented significant effects by reducing licking behavior induced by formalin, capsaicin, and glutamate and increasing the latency time in the hot plate model. Opioidergic, muscarinic, cannabinoid, and serotoninergic pathways seem to be involved in the antinociceptive activity since their antagonists reversed the observed effect. Opioid receptors are partially involved due to tolerant mice demonstrating less antinociception when treated with both compounds. Our data showed a quicker and simpler route for the synthesis of the new ßN-alkanoyl-5-hydroxytryptamides. Both compounds demonstrated significant antinociceptive effects. These new compounds could be used as a scaffold for the synthesis of analogues with promising antinociceptive effects.

Structural insights into the biological activity of a thioxopyrimidine derivative.

Bacterial resistance to the main widespread antibiotics, such as those based on quinolones, is a concern of the scientific community, leading to the search for new classes of molecules that can be used as an alternative. Here, we investigate the crystalline and chemical characteristics of a thioxopyrimide to understand its demonstrated biological activity and to identify which portion of the molecule can be used as a framework to develop new antibiotics. For this purpose, structural studies of ethyl 4-methyl-2-phenyl-6-thioxo-1,6-dihydro-5-pyrimidinecarboxylate were carried out aided by Hirshfeld surface analysis, as well as theoretical calculations on frontier molecular orbitals, molecular electrostatic potential, and conformational stability, in addition to docking studies targeting topoisomerase IV. The docking results show a reasonable accommodation of the molecule at the topoisomerase IV binding site and interact mainly by hydrogen bonds between the thioxopyrimidine portion with Glu198, Thr292, and Gly225, aided by hydrophobic interactions involving the rest of the molecule. These results suggest a relationship between the antibacterial activity shown mainly with the 4-thioxopyrimidine portion, leading to the investigation of new compounds that use this scaffold.

Design, synthesis and cytotoxicity of the antitumor agent 1-azabicycles for chemoresistant glioblastoma cells.

Twelve multi-functional pyrrolizidinones, indolizidinones and pyrroliazepinones were prepared from formal aza-[3 + 2] and aza-[3 + 3] cycloadditions of five- to seven-membered heterocyclic enaminones as diverse ambident electrophiles. The antitumor activity of these alkaloid-like compounds was investigated through an initial screening performed on human glioblastoma multiform (GBM) cell lines (GL-15, U251), on murine glioma cells line (C6) and on normal glial cells. Of the compounds tested, the new pyrrolo[1,2a]azepinone, [ethyl (3-oxo-1,2-diphenyl-6,7,8,9-tetrahydro-3H-pyrrolo[1,2a]azepin-9a(5H)-yl)acetate] or (Compound-13) exhibited selective cytotoxic effects on GBM-temozolomide resistant cells. Compound-13 exerted dose-dependent cytotoxic activity by promoting arrest of cells in the G0/G1 phase of the cell cycle in the first 24 h. The apoptotic effect observed was in a time-dependent manner. Anti-migratory effect promoted by the treatment with compound-13 was also observed. Moreover, healthy mixed glial cell cultures from rat brain exhibited no cytotoxicity effect upon exposure to compound-13. Thus, the present study paves the way for the use of compound-13 as novel antitumor scaffold candidate for glioma cell therapy.

Mapping the Biotransformation of Coumarins through Filamentous Fungi.

Natural coumarins are present in remarkable amounts as secondary metabolites in edible and medicinal plants, where they display interesting bioactivities. Considering the wide enzymatic arsenal of filamentous fungi, studies on the biotransformation of coumarins using these microorganisms have great importance in green chemical derivatization. Several reports on the biotransformation of coumarins using fungi have highlighted the achievement of chemical analogs with high selectivity by using mild and ecofriendly conditions. Prompted by the enormous pharmacological, alimentary, and chemical interest in coumarin-like compounds, this study evaluated the biotransformation of nine coumarin scaffolds using Cunninghamella elegans ATCC 10028b and Aspergillus brasiliensis ATCC 16404. The chemical reactions which were catalyzed by the microorganisms were highly selective. Among the nine studied coumarins, only two of them were biotransformed. One of the coumarins, 7-hydroxy-2,3-dihydrocyclopenta[c]chromen-4(1H)-one, was biotransformed into the new 7,9-dihydroxy-2,3-dihydrocyclopenta[c]chromen-4(1H)-one, which was generated by selective hydroxylation in an unactivated carbon. Our results highlight some chemical features of coumarin cores that are important to biotransformation using filamentous fungi.

Multiple response optimization of alkaline pretreatment of sisal fiber (Agave sisalana) assisted by ultrasound.

A procedure for the alkaline pretreatment of sisal fiber assisted by ultrasound was optimized to obtain a higher solubilization of hemicellulose and the removal of lignin with cellulose fraction maintenance. A full factorial design 23 was used for the evaluation of the effects of the variables (sonication time, NaOH concentration, and sonication amplitude) on the pretreatment. The optimal values for the variables using the Doehlert matrix for the sonication time, NaOH concentration, and sonication amplitude were 27 min, 4.1% (m/v), and 50%, respectively. The X-ray diffractometry and scanning electron microscopy analyses, after pretreatment, showed changes in chemical structure and morphology due to the removal of 82% of hemicellulose and 86% of lignin from sisal fiber. The soft reaction conditions and relatively short times demonstrated the effectiveness of the combined action of ultrasound with alkaline pretreatment to improve the accessibility to cellulose in this important step of the ethanol production process from biomass.

Single port laparoscopic splenectomy for wandering spleen with splenomegaly in a patient with Wolf-Hirschhorn syndrome.

Wolf-Hirschhorn syndrome is a rare genetic condition characterized by typical facial appearance, growth delay, psychomotor retardation and seizures, with a mosaic of other abnormalities reported in the literature. The occurrence of symptomatic wandering spleen with massive splenomegaly and with an indication for splenectomy has not been yet described for this disease. This study reports the first case in the literature of single port splenectomy for this rare condition. In a 21-year-old female patient with Wolf-Hirschhorn syndrome, with abdominal pain and the diagnosis of wandering spleen with splenomegaly (25 cm diameter) led to an indication of elective splenectomy. In supine position under general anesthesia, single port umbilical splenectomy was performed without laparoscopic assistance, splenic vessels were ligated by sutures, and the specimen was transumbilically extracted. Operative time was 85 min, with minimal bleeding, and resumed oral intake on the same day. No intraoperative or post-operative complications occurred, and the patient was discharged in 48 h. Single port access splenectomy is feasible and is evolving as an attractive alternative therapy for hematological diseases requiring splenectomy.

Inhibition of Paracoccidioides lutzii Pb01 isocitrate lyase by the natural compound argentilactone and its semi-synthetic derivatives.

The dimorphic fungus Paracoccidioides spp. is responsible for paracoccidioidomycosis, the most prevalent systemic mycosis in Latin America, causing serious public health problems. Adequate treatment of mycotic infections is difficult, since fungi are eukaryotic organisms with a structure and metabolism similar to those of eukaryotic hosts. In this way, specific fungus targets have become important to search of new antifungal compound. The role of the glyoxylate cycle and its enzymes in microbial virulence has been reported in many fungal pathogens, including Paracoccidioides spp. Here, we show the action of argentilactone and its semi-synthetic derivative reduced argentilactone on recombinant and native isocitrate lyase from Paracoccidioides lutzii Pb01 (PbICL) in the presence of different carbon sources, acetate and glucose. Additionally, argentilactone and its semi-synthetic derivative reduced argentilactone exhibited relevant inhibitory activity against P. lutzii Pb01 yeast cells and dose-dependently influenced the transition from the mycelium to yeast phase. The other oxygenated derivatives tested, epoxy argentilactone and diol argentilactone-, did not show inhibitory action on the fungus. The results were supported by in silico experiments.

Anti-inflammatory and immunomodulatory effects of RDV-8 [C18H22N2O2S (ethyl 1-butyl-6-methyl-2-phenyl-4-thioxo-1,4-dihydropyrimidine-5-carboxylate)] in a rat model of induced pleurisy and in vitro lymphoproliferation.

RDV-8 [C(18)H(22)N(2)O(2)S (ethyl 1-butyl-6-methyl-2-phenyl-4-thioxo-1,4-dihydropyrimidine-5-carboxylate)] is derived from the 4-thioxopyrimidine, and presents important clinical effects. The present study explored the RDV-8 effects in the proliferation of human peripheral blood mononuclear cells (PBMCs), as well as in a pleurisy-induced rat model. PBMCs were directly plated in four different RDV-8 concentrations (0.0125, 0.025, 0.05 and 0.1 mg/mL). RDV-8 decreased cell proliferation and monocyte chemotactic protein 1 synthesis. The interleukin 1 levels and the cytotoxic effect were not significantly affected by RDV-8 treatment. In the carrageenan-induced pleurisy model, the RDV-8 (3 mg/kg) treatment induced a significant reduction in the exudate volume, in the polymorphonuclear leukocyte migration and in the pleural exudate NO levels. The results indicate that RDV-8 may have an immunomodulatory effect, as well as anti-inflammatory actions suggesting that it could represent a new strategy in the inflammatory response modulation.

Antitumor activity of (-)-alpha-bisabolol-based thiosemicarbazones against human tumor cell lines.

A series of thiosemicarbazones deriving from the natural sesquiterpene (-)-alpha-bisabolol were synthesized and tested against a panel of eight human tumor cell lines to evaluate their anti-tumor potential. Some of the compounds exhibited inhibitory effects on the growth of a wide range of cancer cell lines, but myeloid leukemia cells (K-562) were especially sensitive to all tested thiosemicarbazones (GI(50) 0.01-4.22 microM). Among the analogues, the ketone derivative 3l was the most active, exhibiting potent antitumoral activity (GI(50) 0.01 microM) and high selectivity for K-562 cells (deltaTGI 505). It also demonstrated high cytotoxicity, with an LC(50) of 1.55 microM for the K-562 cells, but it showed only moderate selectivity (deltaLC(50) 38.5 microM). Through structure-activity relationship studies, we identified some structural requirement for the antitumoral activity exhibited by these promising compounds.

catena-Poly[[[1-benzoyl-2-(2-hydroxyethyl)-3-(2-pyridyl)guanidine]chloridocopper(II)] chloride 0.61-hydrate].

The title copper(II) complex, {[CuCl(C(15)H(16)N(4)O(2))]Cl.0.61H(2)O}(n), is a one-dimensional zigzag coordination polymer structure extending along the (010) direction. The Cu(II) atom has a square-pyramidal geometry, where the basal plane is formed by two cis N atoms and one O atom from the ligand, and by a Cl atom. The apical position is occupied by a carbonyl O atom from a symmetry-related molecule. In the crystal structure, there are O-H...Cl and N-H...Cl hydrogen bonds, which link parallel polymer chains along the c direction, so building a two-dimensional structure via the interstitial Cl atoms.

Molecular dynamics investigation with the time resolved optical Kerr effect on the CS2-C6H6 mixtures.

An investigation of the molecular dynamics in pure liquids and in mixtures through the technique of time resolved optical Kerr effect is performed. The samples studied were the mixtures of carbon disulfide (CS(2)) with benzene (C(6)H(6)). The molecular dynamics of the pure liquids is briefly discussed while the main results are obtained for the mixtures. A slow dynamics component is observed for the optical heterodyne detected optical Kerr effect transient decaying exponentially with time constants on picosecond time scale. The fast subpicosend time relaxations are analyzed in terms of the nondiffusive component of the spectral response that is associated with the molecular dynamics. The modifications of the spectrum are quantified, and the explanation of the observed changes is given in terms of the structural interaction configurations that produced changes in the intermolecular potential within which the molecules execute librational motions.

Time-resolved optical Kerr-effect investigation on CS2/polystyrene mixtures.

The relaxation dynamics of carbon disulfide are investigated in mixtures with polystyrene (PS) using the time-resolved optical heterodyne-detected optical Kerr effect (OHD-OKE). The data are analyzed using both the model-dependent approach, which assumes four distinct temporal responses, and the model-independent Fourier transform approach, which generates a spectral response that can be compared with results obtained by depolarized Rayleigh scattering. A slow dynamics is observed for the OHD-OKE transient decaying exponentially with a time constant that varies from 1.68 ps for neat CS2 to 3.76 ps for the most concentrated CS2PS mixture. The increase of this time constant accompanies an increase in the viscosity of the mixture, so we can associate this component with the diffusive reorientation process of the induced polarizability anisotropy of the carbon disulfide in the mixture. The short-time nuclear response is characterized in the frequency domain by a broad band that peaks around 30 cm(-1) for neat carbon disulfide, and is associated with a complex relaxation pattern. The vibrational distribution shifts to higher frequencies when the PS concentration is increased in the mixture. This result is discussed in terms of an increase in the interaction strength between the PS phenyl rings and the carbon disulfide molecules.