Methanolic Potassium Hydroxide Research Articles

Synthesis, characterization, and electrocatalytic behaviour of hydrothermally grown nanostructured La2 O3 and La2 O3 /K-complex.

Rare earth metals play a conspicuous role in magnetic resonance imaging (MRI) for detecting cancerous cells. The alkali metal potassium is a neurotransmitter in the sodium-potassium pump in biomedical sciences. This unique property of rare earth metals and potassium drew our attention to carry forward this study. Therefore, in this work, previously synthesized potassium (K) complexes formed by the reflux of 4-N,N-dimethylaminobenzoic acid (DBA) and potassium hydroxide in methanol, and named [(μ2-4-N,N-dimethylaminobenzoate-κO)(μ2-4-N,N-dimethylaminobenzoic acid-κO)(4-N,N-dimethylaminobenzoic acid-κO) potassium(I) coordination polymer)] were treated hydrothermally with La2 O3 nanomaterials to obtain a nanohybrid La2 O3 /K-complex. After that, the K-complex was analyzed using single-crystal X-ray diffraction and 1 H and 13 C NMR spectroscopy. In addition, the structural and morphological properties of the as-prepared nanostructured La2 O3 /K-complex were also characterized, which involved an investigation using X-ray diffraction (XRD)spectroscopy, Fourier transform infrared (FTIR) spectroscopy, atomic force spectroscopy (AFM), transmission electron microscopy (TEM), and energy dispersive X-ray (EDX) analysis. After this, the electrochemical redox behaviour of the synthesized nanohybrid material was studied using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Therefore, the results from these studies revealed that the as-prepared material was a La2 O3 /K-complex that has a promising future role in sensing various analytes, as it showed effective electrocatalytic behaviour.

Efficient Depolymerization of Glass Fiber Reinforced PET Composites.

The transition to an eco-friendly circular materials system for garbage collected after use from end-users is a serious matter of concern for current society. One important tool in this challenge to achieve a truly circular economy is the chemical recycling of polymers. It has previously been demonstrated that chemical recycling is a feasible alternative to reach carbon circularity, which promotes the maximization of carbon recovery through all possible means. Among the advantages of chemical recycling, one must highlight its ability to selectively attack one or several target functionalities inside a complex mixed stream of polymers to obtain pure monomers, which can then be used to prepare virgin-like polymers as a final product. In previous works from our group, we used a microwave-heated potassium hydroxide in methanol (KMH) system to instantaneously depolymerize PET bottles. The KMH system was also effective for polycarbonate (PC), and intimately mixed PET/PC blends. In the present study, glass fiber reinforced (GFR) PET composites were submitted to depolymerization using the KMH system, and it was verified that more strict conditions were required for full depolymerization of GFR pellets than for pure PET pellets. Evidence of the reorganization of PET chains leading to increased crystallinity were obtained through DSC and WAXD. Surface adhesion of PET and crystallization onto glass fibers led to a different crystalline phase that seems to be more protected against the depolymerization solution, thus increasing the time required for full depolymerization when compared to unreinforced PET. An activation energy of 123 kJ/mol was estimated, in the same range of pristine PET pellets and PET bottles. The optimization of depolymerization conditions permitted 100% depolymerization within 5 min of reaction at 120 °C using 30 mL of KMH solution per g of composite. The green chemistry metrics reflect that our system is more efficient than most of the depolymerization systems found in the literature. The optimal depolymerization conditions here reported for GFR PET composites represent another step towards a total recycling system that includes not only pure polymers but also composites, commonly present in daily life.

GC–MS/MS method for determining quizalofop ethyl, quizalofop tefuryl, and their metabolites in foods

A gas chromatography–tandem mass spectrometry (GC–MS/MS) method was developed for the quantitative analyses of quizalofop ethyl and quizalofop tefuryl herbicides as well as their metabolites (i.e., quizalofop and its conjugates). This method fulfills the residue definition established by Japan. Following sample reflux in a methanolic potassium hydroxide solution, the residues were converted to 6-chloro-2-methoxyquinoxaline (CMQ) and extracted with hexane. Cleanup was carried out using primary secondary amine and silica gel cartridges prior to GC–MS/MS analysis. The developed method was validated for quizalofop ethyl, quizalofop tefuryl, and quizalofop in six foods at 0.01 mg/kg and at their maximum residue limits set by Japan. A satisfactory analytical performance was achieved (trueness = 80–93%, relative standard deviation = 1–7%, limit of detection = 0.00025 mg/kg for all analytes), and no significant matrix effects were observed for the examined matrices. There were no interfering peaks near the retention time of CMQ, indicating the high selectivity of this method. A satisfactory recovery was also achieved for propaquizafop in soybeans, indicating that the proposed method also complies with the residue definition established by the European Union. This method is suitable for the regulatory analysis of quizalofop ethyl and quizalofop tefuryl residues.

Physiochemical properties of biodiesel produced from ogbono (Irvingia gabonesis) seed oil

Biodiesel is a promising alternative fuel and has gained significant attention due to the predicted depletion of conventional fossil fuels and environmental concerns. This study aims to produce biodiesel from ogbono seed oil (using 98 ml methanol and 2g potassium hydroxide (KOH) as a catalyst) via transesterification process and to determine the physiochemical properties of the biodiesel produced. The physiochemical properties of the feedstock (extracted ogbono seed oil) were also determined before the transesterification process. The physiochemical properties of the produced biodiesel showed that it has a density of 0.5±0.00 g/cm3, pour point of 2.0±0, saponification value of 58.90±0.06 mg KOH/g, ester value of 98.0±0.5% (m/m), iodine value of 26.64±0.15gI2/100g, acid value of 0.28±0.05 mgKOH/g, moisture value of 0.0006 ±0.0% and trace amounts of ash content. The results of the physiochemical properties of the produced biodiesel agree with ASTM-D6751 and EN 14214 standard. Thus, it was concluded that ogbono seed oil is an excellent feedstock for biodiesel production via base catalyzed transesterification process

Impact of different cooking methods on polycyclic aromatic hydrocarbons in rabbit meat.

The influence of a variety of cooking methods (poaching, boiling, grilling (charcoal or gas)), frying (pan, deep frying, and stir frying) with a variety of oils (vegetable oil, extra virgin olive oil, sesame oil, extra light olive oil, and sunflower oil), microwaving, and oven roasting on polycyclic aromatic hydrocarbons (PAHs) formation in rabbit meat samples was investigated. Meat samples (including three replicates) were prepared without additives or spices. PAHs extraction was carried out by saponification method with potassium hydroxide in methanol which was followed by a silica gel column technique and the samples were quantified by using gas chromatography with mass spectrometry (GC‐MS). PAHs standards, fluorene, naphthalene, anthracene, phenanthrene, pyrene, acenaphthalene, fluoranthene, and benzopyrene, were used for this study. The other PAHs except fluorene were not observed (detection limit‐0.009 µg/g) in all the samples. Among traditional processing techniques, higher PAH contents were observed as a result of frying. Frying with vegetable oil produced higher fluorene content (0.06–0.13 µg/g) in the deep‐fried sample, although sesame oil is the best oil which produces lowest PAH contents in fried samples. Among all the processing techniques, lower fluorene (0.01–0.02 µg/g) content was noticed in poaching. Benzo(a)pyrene was not observed in all the investigated samples which is viewed as a reliable strategy of the cooking process for human consumption. After processing, the cooking loss was determined and oven roasting and grilling exhibited greater moisture loss.

Physicochemical characterization of the pulp oil of bacuri Attalea phalerata Mart. ex Spreng. (Arecaceae)

The aim of the study was to characterize the pulp oil of bacuri Attalea phalerata Mart. ex Spreng. (Arecaceae) according to official analytical methods. Total phenolic and carotenoids contents were evaluated by spectrophotometry, and tocopherols composition by high-performance liquid chromatography. The fatty acid profile was obtained through gas chromatography from samples transesterified with potassium hydroxide in methanol and n-hexane. According to the proximate composition, bacuri pulp contained 41.5 % carbohydrates and 39.2 % lipids. Regarding its physicochemical properties, the oil showed a free fatty acids content of 0.7 %, a peroxide value of 1.4 meq/kg, a refractive index of 1.463, an iodine number of 84.3 g I2/100 g, a saponification number of 193.5 mg KOH/g, an unsaponifiable matter of 0.5 %, and 48.7 h of oxidative stability. Total phenolic, carotenoids, and tocopherols contents recorded values of 2.4 mg GAE/g, 243.0 µg/g, and 86.8 mg/kg, respectively. The bacuri oil showed a fatty acid composition similar to olive oil and a high percentage of unsaturation, finding 67.3 % of monounsaturated acids, and 11.3 % of polyunsaturated acids. The main fatty acids were oleic (67.3 %), palmitic (13.3 %), and linoleic (10.5 %). Due to its physicochemical characteristics, bacuri oil has a great potential to be used in food preparations, such as salad oil or in margarine formulation.

Evaluation of Ethylated Phenylcarbamoylazinane‐1,2,4‐Triazole Amides Derivatives as 15‐Lipoxygenase Inhibitors Together with Cytotoxic, ADME and Molecular Modeling Studies

AbstractSearching the organic compound as anti‐inflammatory agent is a fruitful effort to treat inflammatory disorders such as asthma, arthritis, psoriasis, and especially cancer. These disorders can be cured by lipoxygenase (LOX) inhibitors, which have the ability to stop the development and progression of inflammation. The present research described the synthesis of fifteen new N‐alkyl/aralkyl/aryl derivatives (7 a–o) of 2‐(4‐ethyl‐5‐(1‐phenylcarbamoyl)piperidine‐4H‐1,2,4‐triazol‐3‐ylthio)acetamide by the continuous conversions of ethyl piperidine‐4‐carboxylate (a) into phenylcarbamoyl derivative (1) hydrazide (2), semicarbazide (3) and finally the N‐ethylated 5‐(1‐phenylcarbamoyl)piperidine‐1,2,4‐triazole (4). The target molecules (7 a–o) were formed by the reaction of 4 with various electrophiles (6 a–o), in methanolic potassium hydroxide. These synthetic analogues were characterized by FTIR, 1H, 13C NMR spectroscopy, EIMS, and HREIMS spectrometry. The compounds 7 a–o were screened for their inhibitory potential against 15‐lipoxygenase. Compounds 7 b, 7 e, 7 c and 7 g displayed the potent inhibitory potential (IC50 17.52±0.67, 35.61±0.81, 36.24±0.83 & 36.52±0.58 μM, respectively), whereas, moderate inhibition was shown by 7 h, 7 a, 7 d with IC50 values between 42.95±0.73 to 45.67±0.75 μM, respectively. Some compounds exhibited drug‐like characteristics due to their lower cytotoxic and good ADME profiles and supported by molecular modeling studies where one of the NH groups was found engaged through hydrogen bonding with Ala672. The carbonyl group amide and Asn554 were connected by a hydrogen bond, whereas the second NH group was also linked through hydrogen bonds with Gln363.

Gas Chromatography–Mass Spectrometric (GC-MS) Determination of Polycyclic Aromatic Hydrocarbons in Smoked Meat and Fish Ingested by Bangladeshi People and Human Health Risk Assessment

This study investigated the human health risk assessment of polycyclic aromatic hydrocarbons (PAHs) (naphthalene, fluorene, phenanthrene, anthracene, pyrene, benzo(a)anthracene, chrycene, and benzo(a)pyrene) from the consumption of smoked fish (Coral, Telapia, Shrimp, and Rupchanda) and smoked meat (Beef Shikh Kabab, Mutton Shikh Kabab, Kashmiri Kabab, and Chicken Grill) highly consumed by Bangladeshi people quantified by gas chromatography-mass spectrometry (GC-MS) technique. The samples were hydrolyzed in methanolic potassium hydroxide solution and treated with cyclohexane for the extraction of the PAHs from the samples and then subjected to GC-MS technique for the analyses of PAHs. Results showed that the minimum and maximum mean concentrations of the aforesaid PAHs were found to be 19.23 and 294.50 µg/kg in smoked meat, and 4.18 and 4.54 µg/kg in smoked fish samples. Of the carcinogenic PAHs, benzo(a)pyrene (BaP) was the most representative in smoked meat samples ranging from 6.68 to 46.90 µg/kg that exceeded the 5.0 µg/kg maximum level for smoked meat and smoked fish set by the European Commission (EC Regulation No 1881/2006).The present data indicate that all of the smoked meat are unsafe for human consumption. Mathematically calculation representing the carcinogenic risk value of targeted compounds was −4 within the acceptable range of 1.0 × 10−6 to 1.0 × 10−4 (USEPA, 1989). The spike recovery of PAHs was ranging from 70.0 to 90.5% that demonstrated the perfect reliability and accuracy of the methodology employed in this study.

New Differently Functionalized Cyclopentenediones

2-Allyl-2,4-dichloro-5-(2,4,6-trimethoxyphenyl)cyclopent-4-ene-1,3-dione reacted with highly nucleophilic secondary (diethylamine, morpholine, N-methylpiperazine, piperidine) and primary amines (allylamine) under mild conditions (methanol, 20°C, 24 h) to give products of substitution of the 4-chlorine atom in 60–87% yield. The reaction of the same compound with a weak nitrogen nucleophile, imidazole, afforded 4-(1H-imidazol-1-yl) derivative in a low yield (25%). Methionine methyl ester hydrochloride failed to react with 2-allyl-2,4-dichloro-5-(2,4,6-trimethoxyphenyl)cyclopent-4-ene-1,3-dione in methanolic potassium hydroxide; instead, 55% of 2-allyl-2-chloro-4-methoxy-5-(2,4,6-trimethoxyphenyl)cyclopent-4-ene-1,3-dione was obtained. The reaction with methyl 2-sulfanylacetate in the presence of sodium hydride produced methyl {[4-allyl-4-chloro-3,5-dioxo-2-(2,4,6-trimethoxyphenyl)cyclopent-1-en-1-yl]sulfanyl}acetate in 47% yield.

(2Z)-2,3,4,5,5-Pentachloropenta-2,4-dienic acid as a minor product in the synthesis of 5,5-dimetoxytetrachlorocyclopentadiene from hexachlorocyclopentadiene

Pentachloropentadienic acid was isolated, apart from the expected 5,5-dimetoxytetrachlorocyclopentadiene, in the reaction of hexachlorocyclopentadiene with potassium hydroxide in methanol. The structure of this minor product was established by X-ray crystallography. The plausible mechanism of its formation is discussed.

Direct saponification of wet microalgae by methanolic potassium hydroxide using acetone as co-solvent

The fatty acids of microalgae are promising source of biodiesel and omega-3 fatty acids. The objective of this study is extraction of fatty acids from wet Dunaliela salina by direct saponification using methanolic potassium hydroxide and a suitable co-solvent. The study identified acetone as an efficient co-solvent for saponification of wet microalgal biomass by methanolic potassium hydroxide. The presence of acetone in methanolic KOH saponification produced 24% more fatty acid than its absence. Further optimization of concentration of acetone (80% v/v), concentration of potassium hydroxide (0.1% v/v) and solvent-dry biomass ratio (75:1) resulted in a maximum yield of 98% fatty acid. The proposed acetone assisted saponification of wet microalgal biomass could serve as an energy efficient route for fatty acid production since the reaction happens under room temperature and normal atmospheric pressure without any cell lysis or drying the biomass.

Rapid and easy carotenoid quantification in Ghanaian starchy staples using RP-HPLC-PDA

This study comprises the development of a robust, rapid and cost-effective reversed-phase high-performance liquid chromatographic method with low solvent consumption (micro-approach) to quantify carotenoids in starchy staples, exemplified for cassava, maize and plantain matrices. For extraction, a mixture of 1 M potassium hydroxide in methanol and hexane (1:1) was used, enabling the simultaneous extraction and saponification of the sample extracts. Carotenoids were separated within 12 min on a C30 column using mixtures of methanol, methyl tert-butyl ether and water as mobile phases. Due to the implemented saponification process, the technique showed the potential to be applied for carotenoid analysis in other sample matrices exemplarily demonstrated for green leafy vegetables. Because of the low application and equipment costs, the analytical procedure qualifies for its application in quality management with limited budget. Concentrations of five major dietary carotenoids (lutein, zeaxanthin, β-cryptoxanthin, α-carotene and β-carotene) in cassava, cocoyam, yam, maize and plantain samples from the Ashanti region of Ghana were determined. Based on the restricted data on carotenoid contents of food available in West Africa, the results provide valuable additional information that can be used to expand local food composition tables and support the assessment of dietary carotenoid intake.

LC-PDA/APCIitMS identification of algal carotenoid and oxysterol precursors to fatty acid esters in hydrolyzed extracts of the freshwater mussel Dreissena bugensis

Carotenyl fatty acid esters (carotenyl-FAEs) were extracted in acetone from freeze-dried Dreissena bugensis (Lakes Erie and Ontario) and hydrolyzed to identify the carotenoid precursors. Analysis by liquid chromatography (LC) with photodiode array (PDA) and atmospheric pressure chemical ionization-ion trap mass spectrometry (APCIitMS) revealed the major hydrolysis products: fucoxanthinol (FOH) from fucoxanthin (FX, diatoms); mactraxanthin (MX) from violaxanthin (VX, chlorophytes); 4-fold higher levels of an unknown, tentatively identified as an adduct of two closely eluting C27H46O3 and C27H48O3 steryl triols. Enzymatic hydrolysis (Candida rugosa) of dreissenid extracts yielded FOH and MX, but residual carotenyl-FAEs remained. Alkaline hydrolysis yielded isoFOH, MX, and steryl triols, without residual carotenyl-FAEs: isoFOH decreased, but two FOH hemiketal by-products increased, when the dose of potassium hydroxide in methanol was too high. The PDA detector profiled carotenyl-FAEs and products of enzymatic and alkaline hydrolysis, without interference. The APCIitMS detector revealed carotenoid and oxysterol products of alkaline hydrolysis but was adversely affected by background from bile salts used for enzymatic hydrolysis. LC retention times and elution order were correlated to solubility parameters, calculated from the analyte structure, to cross-check MS interpretations. A multiple linear regression of LC retention times on solubility parameters for 12 carotenoid standards included FOH, isoFOH, and MX (r 2 0.97). The model revealed the close similarity of polar carotenoid metabolites to C27-steryl triols tentatively identified by APCIitMS, suggesting that further LC-MS analyses would be beneficial, to explicitly link oxysterols and the polar carotenoids, as metabolites of algal precursors in the dreissenid diet. Graphical abstract Methods of analysis and major neutral products of hydrolysis from fatty acid esters in D. bugensis.

Utilidad de un método que determina simultáneamente retinol y α-tocoferol en leche materna por cromatografía líquida de alta resolución

ObjectiveTo present the results obtained in the development of a simplified method, with a direct extraction of breast milk and detection by reverse phase high-performance liquid chromatography of retinol and α-tocopherol. Materials and methodsAn experimental 2x3 factorial design was used, with temperature variables, type of solvent and antioxidant effect, at 2 levels. Subsequent to the extraction, the samples were saponified with potassium hydroxide in methanol, then extracted with petroleum ether, and dried and reconstituted with ethanol. The chromatography conditions were established using microbondapak columns with UV/visible detector: methanol/water (96:4) mobile phase, wavelength for retinol 325, and 290nm for α-tocopherol. ResultsThe analytics parameters were: linearity; r2=0.9955 (retinol), r2=0.9808 (α-tocopherol); detection and quantification limits: 1.1μg/dL and 2.7μg/dL (retinol), 0.9μg/dL and 2.3μg/dL (α-tocopherol). Method accuracy: the within-day relative standard deviation was 4.5%, and a between-day relative standard deviation of 4.8% for retinol, and 4.9% within-day and 4.1% between-day forα-tocopherol. For accuracy, recovery=85.8±7.8% for retinol and 98±1.9% for α-tocopherol. Once validated, the method was applied to the quantification of retinol and α-tocopherol in 100 samples of breast milk. The values obtained were 63.9±5.2μg/dL for retinol and 359.0±115.0μg/dL for α-tocopherol. ConclusionThe method is selective, linear, precise, sensitive and accurate. These characteristics together with their simplicity make the validated method convenient for the determination of retinol and α-tocopherol in breast milk.

Organotin(IV) complexes with 2-hydroxynaphthaldehyde-N(4)-ethylthiosemicarbazone: Synthesis, characterization, and in vitro antibacterial activity

GRAPHICAL ABSTRACT

Interspecies and seasonal differences of retinol in dairy ruminant´s milk

Milk is an essential source of macronutrients and among lipophilic vitamins is significant source of retinol. The contribution of milk to the reference daily intake for retinol varies from 11% to 16%, worldwide. The most consumed dairy products are fresh, dehydrated and condensed milk in which the amonuts of retinol are not modified to those of in whole milk. Retinol is essential to ensure a good functionality of the immune system and plays a critical role in vision, reproduction, cell differentiation as well as growth and development and is found only in animal tissues. The aim of our study was to evaluate the interspecies differences in the retinol concentration of whole raw bovine, caprine and ovine milk and to observe seasonal variation of retinol in bulk tank milk samples. Samples of raw milk were colleceted on different farms in the Czech Republic between 2013 and 2014. Retinol was measured by ultra high performance liquid chromatography with UV detection (325 nm) in isocratic mode after alkaline saponification with methanolic potassium hydroxide solution and liquid-liquid extraction into non polar organic solvent of whole raw milk. To avoid vitamin losses or degradation during the procedure, antioxidants were added to the sample extraction media. Our results indicate significant interspecies differences between bovine and ovine milk and caprine and ovine milk. Concentration of retinol is very similar in bovine and caprine milk 0.96 ±0.11 mg/L, 0.94 ±0.25 mg/L, respectively. The mean concentration in sheep´s milk is 1.75 ±0.24 mg/L. The seasonal variation of retinol in raw bovine milk was detected as high significant, with the highest concentration during winter. These results contribute to the nutrition evaluation of milk in the Czech Republic and indicate, that the sheep´s milk is the best source of retinol among the milks of ruminants kept in the Czech Republic, however it is not used in its fluid form for human consumption.

Amino Acid and Fatty Acid Profile of the Mare's Milk Produced on Suusamyr Pastures of the Kyrgyz Republic During Lactation Period

The high nutritional and health-promoting properties of kymyz, a traditional drink of nomads produced from mare's milk, are well-known and reported in literature. The composition of mare's milk is significantly different from that of cow and other ruminants. Fatty acid composition and amino acid profile of mare's milk produced at Suusamyr pastures of Kyrgyzstan were studied during four lactation months (May, June, July and August). The amino acid composition was determined by precolumn derivatization with diethyl ethoxymethylenemalonate (DEEMM) in high-performance liquid chromatography (HPLC) and 18 amino acids were determined in mare's milk. Most abundant amino acids were glutamic acid (16.8-21.2%), leucine (8.2-10.1%), lysine (8.9-10.1%) and ornithine (0.1-0.7%) was in a small amount. The percentages of essential AA in protein of mare milk were 46%, 46%, 51%, 48% for May, June, July and August months respectively, which demonstrate the high biological value of milk during all milking season. The fatty acid contents of the milk fat were determined in the form of fatty acid methyl esters by gas chromatograph after methylation with potassium hydroxide in methanol. The concentrations of capric (10:0), lauric (12:0) and myristic acid (14:0) were similar during four lactation months and the concentration of linoleic acid (18:2) was higher in July month. The results of the study have shown that the highest contents of the nutritive compounds were found in the mare's milk obtained in July.

Synthesis of Highly Concentrated ZnO Nanorod Sol by Sol-gel Method and their Applications for Inverted Organic Solar Cells

The effects of the zinc oxide (ZnO) preparing process on the performance of inverted organic photovoltaic cells (OPVs) were explored. The morphology and size of ZnO nanoparticles were controlled, leading to more efficient charge collection from device and higher electron mobility compared with nanospheres. Nanosized ZnO particles were synthesized by using zinc acetate dihydrate and potassium hydroxide in methanol. Also, water was added into the reac- tion medium to control the morphology of ZnO nanocrystals from spherical particles to rods, and NH 4 OH was used to prevent the gelation of dispersion. Solution-processed ZnO thin films were deposited onto the ITO/glass substrate by using spin coating process and then ZnO films were used as an electron transport layer in inverted organic photovoltaic cells. The analyses were carried out by using TEM, FE-SEM, AFM, DLS, UV-Vis spectroscopy, current density-voltage characteristics and solar simulator.

ACETYLCHOLINESTERASE INHIBITION ACTIVITY OF SOME QUINOLINYL SUBSTITUTED TRIAZOLOTHIADIAZOLE DERIVATIVES.

A series of aralkanoic acids was converted into aralkanoic acid hydrazides through their esters formation. The aralkanoic acid hydrazides upon treatment with carbon disulfide and methanolic potassium hydroxide yielded potassium dithiocarbazinate salts, which on refluxing with aqueous hydrazine hydrate yielded 5-aralkyl-4-amino-3-mercapto-1,2,4-triazoles. The target compounds, 3-aralkyl-6-(substitutedquinolinyl)[1,2,4]triazolo[3,4-b][1,3,4]thiadiazoles, were synthesized by condensing various quinolinyl substituted carboxylic acids with 5-aralkyl-4-amino-3-mercapto-1,2,4-triazoles in phosphorus oxychloride. The structures of the newly synthesized triazolothiadiazoles were characterized by IR, 1H NMR, 13C NMR, and elemental analysis studies. The structure of one of the 5-aralkyl-4-amino-3-mercapto-1,2,4-triazoles was unambiguously deduced by single crystal X-ray diffraction analysis. All the synthesized compounds were screened for their acetylcholinesterase inhibition activities. Four of the triazolothiadiazoles exhibited excellent acetylcholinesterase inhibition activities as compared to the reference inhibitor.

Syntheses, Characterizations, Crystal structures, and Antitumor Activities of Arenetelluronic Triorganotin Esters

Six new arenetelluronic triorganotin esters, namely (R3Sn)4[ArTe(μ-O)(OH)O2)]2 (Ar = Ph, R = Me: 1, R = Ph: 2; Ar = 3-Me-Ph, R = Me: 3, R = Ph: 4, Ar = 3-Cl-Ph, R = Me: 5, R = Ph: 6), were prepared by treating arenetelluronic acids with the corresponding R3SnCl (R = Me, Ph) with potassium hydroxide in methanol. All complexes were characterized by elemental analysis, FT-IR, NMR (1H, 13C, 119Sn) spectroscopy, and X-ray crystallography. The structural analyses indicate that these complexes are isostructural as Sn4Te2 moiety, in which the Te2(μ2-O)2 units are situated in the center and each Te atom is coordinated with two OSnR3 groups on the side. Complexes 1, 3, and 5 show one-dimensional chain and two-dimensional network supramolecular structures by intermolecular CH···O or CH···Cl interactions. The antitumor activities of these complexes reveal that most arenetelluronic triorganotin esters have powerful antitumor activities with certain regularity.