Elemental analysis: an important purity control but prone to manipulations

Elemental analysis is a powerful analytical tool for purity determination. However, it is prone to manipulations. Herein, we introduce an approach to provide original elemental analysis data, allowing verification of the currently just listed values.

Synthesis of new distyrylpyridine analogues bearing amide substructure as effective insecticidal agents

In examining for unique insecticidal agents, two derivatives namely, 2-((3-cyano-4,6-distyrylpyridin-2-yl)thio)-N-(4-nitrophenyl)acetamide (2) and 3-amino-N-(4-nitrophenyl)-4,6-distyrylthieno[2,3-b]pyridine-2-carboxamide (3) were synthesized from distyrylpyridine-2-thione (1). The new compounds were structurally clarified by spectral and elemental analysis data. The insecticidal activity of these compounds were carried out against cowpea aphid, Aphis craccivora Koch. It is demonstrated that the compounds 2 and 3 have noteworthy insecticidal activity against nymphs of cowpea aphid with LC50 values of 0.025-0.027 ppm and 0.005-0.006 ppm after 24 h and 48 h of treatment, respectively. Also, the compounds 2 and 3 have noteworthy insecticidal activity against adults of cowpea aphid with LC50 values of 0.112-0.129 ppm and 0.014-0.015 ppm after 24 h and 48 h of treatment, respectively, that were comparable to that of the control acetamiprid.

Synthesis and characterization of permanent magnetic oxide system Ba1-x-yLaxCeyFe12O19 system doped with La-Ce metal using wet mechanical milling method

The development of permanent magnet-based rare earth metals becomes a serious problem if the raw materials are difficult to find. The solution chosen is to utilize an oxide-based permanent magnet with little substitution of rare earth metals. In this study presented a permanent magnetic synthesis of barium hexaferrite-based oxides that were doped with La and Ce atoms. The synthesis of this material uses the wet mechanical milling technique to obtain the single phase permanent magnet system Ba1-x-yLaxCeyFe12O19 (x = 0, 0.02, 0.04 and y = 0. 0.05, 0.1). The precursor is weighed according to stoichiometric composition and is milled for 5 hours then compressed at a pressure of 7000 Psi. Sintering temperature for the formation of the barium hexaferrite phase at 1200oC for 2 hours. All samples after sintering were characterized using XRD and EDS. A single phase is obtained on all sample compositions with a hexagonal P63/mmc structure and is supported by elemental analysis data that each substituted sample contains elements La and Ce. Lattice parameters a, b, and c appear to decrease with increasing concentrations of La and Ce doping ions with a ratio of c/a in the range of 3.93-3.94.

Composition and Structure of Ethanol-Lignins of Coniferous and Deciduous Wood and Products of their Catalytic Telomerization with 1,3-Butadiene

The composition and structure of ethanol-lignins of coniferous (abies, pine) and deciduous (aspen, birch) wood and products of their catalytic telomerization with 1,3-butadiene has been studied with use of the methods 31P-NMR, gel-permeation chromatography, scanning electron microscopy and elemental analysis. Data on the nature and content of hydroxyl groups in ethanol-lignins were obtained using phosphorylation of lignins with 2-chloro‑4,4,5,5,-tetramethyl‑1,3,2-dioxaphospholane.The studied lignins differ from each other in the content of aliphatic, phenolic and carboxyl groups. The total content of hydroxyl groups increases in the series of ethanol-lignins: birch < aspen < pine < abies. For the modification of ethanol-lignins, the reaction of catalytic telomerization with 1,3-butadiene was used at 70 °C and 90 °C in the presence of a complex of palladium (II) diacetate with the sodium salt of triphenylphosphine trisulfate. By comparing the number of aliphatic, phenolic and carboxyl OH- groups in the initial and telomerized ethanol-lignins, it was found that only aliphatic and phenolic hydroxyl groups participate in the telomerization reaction. Telomerization of ethanol-lignins with 1,3-butadiene increases their average molecular weight and reduces polydispersity. The morphology of telomerized and initial samples of ethanol-lignins varies significantly

SYNTHESIS AND CHARACTERIZATION OF COORDINATION COMPOUNDS OF 3d-METAL MALEATES WITH THIOSEMICARBAZIDE

Complexes of copper(II), nickel(II), cobalt(III), and zinc(II) maleates with thiosemicarbazide were synthesized. The resulting compounds were characterized by the elemental analysis data, infrared spectroscopy, diffuse reflectance spectroscopy, and thermogravimetry.

Synthesis and study of the anticancer activity of some new 7H-[1,2,4]triazolo [3,4-b][1,3,4]thiadiazines

The problem of finding effective low-toxic anticancer agents is one of the most important in modern medicine and pharmacy. Despite a large selection of anticancer drugs and a variety of mechanisms of their action, the effectiveness of existing drugs continues to be insufficient. Among the numerous natural and synthetic heterocyclic compounds that exhibit anticancer activity, 7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazine derivatives, which are able to initiate different pathways of tumor cell death. Based on this, the synthesis of new derivatives of this class of compounds and the study of their anticancer properties is relevant. The aim of the work is to synthesis of new 7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazines and study their anticancer activity. Materials and methods. It was used methods of organic synthesis, physical and chemical methods of analysis organic compounds (1H NMR spectroscopy, elemental analysis). Results. In order to obtain new 7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazines, the interaction implemented of 4-amino-4H-[1,2,4]triazole-3-thiols with the corresponding bromoacetophenones. The reaction proceeds by heating the above reagents in alcohol with the closure of the thiadiazine ring and the formation of 7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazine systems. The structure of all synthesized compounds was confirmed by 1H NMR spectroscopy and elemental analysis data. The study of the anticancer activity of the synthesized compounds was carried out in the framework of the international scientific program DTP (Developmental Therapeutics Program) of the National Cancer Institute (NCI, Bethesda, Maryland, USA). It was found that the synthesized compounds exhibited different levels of anticancer activity. The most active among the tested substances was compound 3j with an average GP value of 28.73. The most sensitive to it were the lines of melanoma MDA-MB-435 and SK-MEL-2, kidney cancer A498 and RXF 393, CNS cancer SNB-75, and non-small cell lung cancer NCI-H522. The secondary stage of studies of this compound confirmed its high anticancer activity against most cancer cell lines. Conclusions. As a result of the interaction of 4-amino-4H-[1,2,4]triazole-3-thiols with the relevant bromoacetophenones, a series of new triazolo[3,4-b][1,3,4]thiadiazines was not described in the literature was synthesized. Testing the synthesized compounds for the antitumor activity made it possible to isolate 1 highly active compound with a pronounced anticancer effect, which in terms of activity approaches or exceeds the known drugs 5-fluorouracil (5-FU) and cisplatin, as well as an anticancer agent, curcumin.

Tetracyclic Heteroaromatic Systems-Synthesis of Ethoxycarbonylphenylpyrido[3',2':5,6] Thiopyranoquinolines

7-benzylideneamino-5H-thiochromeno[2,3-b]pyridin-5-ones and 9-benzylideneamino-5H-thio- chromeno[2,3-b]pyridin-5-ones, on reaction with ethyl pyruvate to afford 1-ethoxycarbonyl-3-phenyl-12H- pyrido[3',2':5,6]thiopyrano[3,2-f]quinoline-12-ones and 4-ethoxycarbonyl-2-phenyl-7H- pyrido[3',2':5,6]thiopyrano[3,2-h]quinoline-7-ones respectively by the two different methods. These products were precipitated by addition of ethanol, water (1:1), were purified by recrystalizing from appropriate solvents and were characterized from their IR, 1H-NMR, mass spectra and elemental analysis data.

A concise and efficient CuI-catalyzed synthesis of diimino dihydroquinazoline derivatives from isocyanides and guanidines derivatives through intramolecular C–H activation

: A novel series of diimino dihydroquinazoline derivatives were synthesized from isocyanides and guanidine analogs in quantitative yields by applying an efficient, inexpensive, one-pot copper-catalyzed intramolecular C-H activation reaction under mild conditions. The structures were confirmed on the basis of IR, 1HNMR, 13C NMR, mass spectral and elemental analysis data. The protocol offers advantages like short reaction time, simple workup process, high yields, and an environmentally benign methodology. Interestingly, better results (yield = 82%) were observed in terms of the yield obtained by using a mixture of CuI, Cs2CO3 and acetonitrile as the catalyst, base and solvent, respectively. The data also suggested that compound 5i is produced with the highest yield (87%) from the corresponding diisopropyl carbon diimide, 4-nitroaniline and phenyl isocyanide. Finally, a mechanistic explanation for the reaction promoted by cuprous iodide (CuI) was proposed on the basis of previous investigations and our experimental observations.

In vitro osteogenic activities of sulfated derivative of polysaccharide extracted from Tamarindus indica L.

Osteoporosis, one of the most serious public health concerns caused by an imbalance between bone resorption and bone formation, has a major impact on the population. Therefore, finding the effective osteogenic compounds for the treatment of osteoporosis is a promising research approach. In our study, tamarind (Tamarindus indica L.) seed polysaccharide (TSP) extracted from tamarind seed was subjected to synthesize its sulfate derivatives. The 1H NMR, FT-IR, SEM, monosaccharide compositions and elemental analysis data revealed that tamarind seed polysaccharide sulfate (TSPS) was successfully prepared. As the result, TSPS showed potent effects on inducing osteoblast differentiation via increasing alkaline phosphatase (ALP) activity up to 20% after 10 days and bone mineralization approximately 58% after four weeks at concentration of 20 μg/mL, whereas no statistically increase for both ALP activity and bone mineralization was observed in TSP treatment. Furthermore, TSPS enhanced expression of several marker genes in bone formation. Overall, the obtained data provided novelty on osteogenic compounds originated from TSP of T. indica, as well as scientific fundamentals on drug development and bone tissue engineering for the treatment of osteoporosis and other bone-related diseases.