scholarly journals A Regioselective Synthesis of Novel Functionalized Organochalcogen Compounds by Chalcogenocyclofunctionalization Reactions Based on Chalcogen Halides and Natural Products

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3729
Author(s):  
Maxim V. Musalov ◽  
Vladimir A. Potapov ◽  
Vladimir A. Yakimov ◽  
Maria V. Musalova ◽  
Arkady A. Maylyan ◽  
...  
Keyword(s):  
Natural Products ◽  
Methylene Chloride ◽  
Solvent System ◽  
Regioselective Synthesis ◽  
Sodium Metabisulfite ◽  
Two Phase ◽  
Sulfur Dichloride ◽  
Selenium Dibromide ◽  
Tellurium Tetrachloride ◽  
Distinguishing Features

The regioselective synthesis of novel functionalized condensed organochalcogen compounds by chalcogenocyclofunctionalization reactions based on chalcogen halides and the natural products thymol and carvacrol has been developed. The reactions of selenium dibromide with allyl thymol and allyl carvacrol proceeded in methylene chloride at room temperature in the presence of NaHCO3 affording bis[(7-isopropyl-4-methyl-2,3-dihydro-1-benzofuran-2-yl)methyl] and bis[(4-isopropyl-7-methyl-2,3-dihydro-1-benzofuran-2-yl)methyl] selenides in 90–92% yield. Similar sulfides were obtained in 70–72% yields by the reaction of sulfur dichloride in chloroform under reflux. Trihalotellanes containing the same organic moieties were synthesized from allyl thymol, allyl carvacrol and tellurium tetrachloride or tetrabromide in quantitative yields. Corresponding functionalized ditellurides were prepared in 91–92% yields by the reduction of the trichlorotellanes with sodium metabisulfite in two-phase solvent system. The comparison of reactivity of sulfur, selenium and tellurium halides in chalcogenocyclofunctionalization and distinguishing features of each reaction were discussed.

Liquid hydrogen chloride solvent system. XII. Reactions of some sulfur, selenium, and tellurium compounds

1969 ◽  
Vol 47 (10) ◽  
pp. 1675-1680 ◽  
Author(s):  
M. E. Peach
Keyword(s):  
Hydrogen Chloride ◽  
Chloride Solution ◽  
Dimethyl Sulfide ◽  
Chloride Ion ◽  
Solvent System ◽  
Sulfenyl Chloride ◽  
Selenium Dichloride ◽  
Sulfur Dichloride ◽  
New Compounds ◽  
Tellurium Tetrachloride

The ions Me2SCl+ and MeSCl2+ have been prepared in hydrogen chloride solution from the oxidation of dimethyl sulfide and methanesulfenyl chloride with chlorine, or from methyl sulfur trichloride (MeSCl2+), and characterized as their tetrachloroborates and hexafluorophosphates. Et2SCl+BCl4− and EtSCl2+BCl4− have been prepared analogously. Dimethyl selenium and dimethyl tellurium solutions were oxidized with chlorine to dimethyl selenium dichloride and dimethyl tellurium dichloride.Methanesulfenyl chloride solution was ionized due to the protonation of sulfur, and not to the loss of a chloride ion. Methylchlorosulfonium hexafluorophosphate has been characterized. Methane- and ethane-sulfenyl chloride solutions reacted with boron trichloride giving (RSCl)2BCl3.Sulfur tetrachloride, selenium tetrachloride, and tellurium tetrachloride were sparingly soluble and showed no acidic or basic properties in the solvent. Sulfur monochloride, sulfur dichloride, selenium monochloride, and tellurium dichloride were non-basic in solution.The new compounds, Me2S2.BCl3 and Me2Te.BCl3, have been prepared and characterized.

Advances in Separation and Purification of Bioactive Polysaccharides through High-speed Counter-Current Chromatography

2020 ◽  
Vol 58 (10) ◽  
pp. 992-1000
Author(s):  
Yu Yang ◽  
Bilal Muhammad Khan ◽  
Xiping Zhang ◽  
Yongjie Zhao ◽  
Kit-Leong Cheong ◽  
...  
Keyword(s):  
Natural Products ◽  
High Speed ◽  
Solvent System ◽  
Future Research ◽  
Phase System ◽  
Separation And Purification ◽  
Two Phase ◽  
Bioactive Substances ◽  
Efficient System ◽  
Counter Current

Abstract Polysaccharides, with an extensive distribution in natural products, represent a group of natural bioactive substances having widespread applications in health-care food products and as biomaterials. Devising an efficient system for the separation and purification of polysaccharides from natural sources, hence, is of utmost importance in the widespread applicability and feasibility of research for the development of polysaccharide-based products. High-speed counter-current chromatography (HSCCC) is a continuous liquid–liquid partitioning chromatography with the ability to support a high loading amount and crude material treatment. Due to its flexible two-phase solvent system, HSCCC has been successfully used in the separation of many natural products. Based on HSCCC unique advantages over general column chromatography and its enhanced superiority in this regard when coupled to aqueous two-phase system (ATPS), this review summarizes the separation and purification of various bioactive polysaccharides through HSCCC and its coupling to ATPS as an aid in future research in this direction.

scholarly journals Tubular Electrospun Vancomycin-Loaded Vascular Grafts: Formulation Study and Physicochemical Characterization

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2073
Author(s):  
Rossella Dorati ◽  
Enrica Chiesa ◽  
Mariella Rosalia ◽  
Silvia Pisani ◽  
Ida Genta ◽  
...  
Keyword(s):  
Methylene Chloride ◽  
Physicochemical Characterization ◽  
Fiber Surface ◽  
Solvent System ◽  
Burst Release ◽  
Sem Images ◽  
Composition And Structure ◽  
Medical Healthcare ◽  
Local Release ◽  
Preformulation Study

This work aimed at formulating tubular grafts electrospun with a size < 6 mm and incorporating vancomycin as an antimicrobial agent. Compared to other papers, the present study succeeded in using medical healthcare-grade polymers and solvents permitted by ICH Topic Q3C (R4). Vancomycin (VMC) was incorporated into polyester synthetic polymers (poly-L-lactide-co-poly-ε-caprolactone and poly lactide-co-glycolide) using permitted solvents; moreover, a surfactant was added to the formulation in order to avoid the precipitation of VMC on fiber surface. A preliminary preformulation study was carried out to evaluate solubility of VMC in different aqueous and organic solvents and its stability. To reduce size of fibers and their orientation, we studied a solvent system based on methylene chloride and acetone (DCM/acetone), at different ratios (80:20, 70:30, and 60:40). Considering conductivity of solutions and their spinnability, solvent system at a 80:20 ratio was selected for the study. SEM images demonstrated that size of fibers, their distribution, and their orientation were affected by the incorporation of VMC and surfactant into polymer solution. Surfactant allowed for the reduction of precipitates of VMC on fiber surface, which are responsible of the high burst release in the first six hours; the release was mainly dependent on graft structure porosity, number of pores, and graft absorbent capability. A controlled release of VMC was achieved, covering a period from 96 to 168 h as a function of composition and structure; the concentration of VMC was significantly beyond VMC minimum inhibitory concentration (MIC, 2 ug/mL). These results indicated that the VMC tubular electrospun grafts not only controlled the local release of VMC, but also avoided onset of antibiotic resistance.

An aqueous two-phase system to pre-purify a heterologously produced siderophore

TECHNOLOGY ◽  
2016 ◽  
Vol 04 (03) ◽  
pp. 135-138
Author(s):  
Mahmoud Kamal Ahmadi ◽  
Samar Fawaz ◽  
Blaine A. Pfeifer
Keyword(s):  
Escherichia Coli ◽  
Natural Products ◽  
Cell Growth ◽  
Complex Nature ◽  
Phase System ◽  
Heterologous Production ◽  
Two Phase ◽  
Aqueous Two Phase System ◽  
Purification System ◽  
Surrogate Host

Natural products span broad activities and applications; however, their access and production are often limited by native cellular sources. As a result, the heterologous production of a siderophore termed yersiniabactin (Ybt) was completed using the surrogate host Escherichia coli. Post-production and purification steps are complicated by the complex nature of most media used for cell growth, prompting the development in this work of an aqueous two-phase pre-purification system capable of rapidly and simply enhancing the concentration of the target Ybt compound.

scholarly journals Estimation of the Effects of Food on the Pharmacokinetic Results in Bioequivalence Studies

2019 ◽  
Vol 70 (8) ◽  
pp. 2805-2810
Author(s):  
Ion Mircioiu ◽  
Valentina Anuta ◽  
Constantin Mircioiu ◽  
Victor Voicu ◽  
Roxana Sandulovici
Keyword(s):  
Statistical Analysis ◽  
Food Intake ◽  
Methylene Chloride ◽  
Internal Standard ◽  
Extraction Yield ◽  
Two Phase ◽  
Peak Areas ◽  
Effect Of Food ◽  
Lower Effect ◽  
Almost All

Paper presents the effect of food on the pharmacokinetics of omeprazole and on the extraction yield of its internal standard, lansoprazole. The experimental data were obtained over three bioequivalence studies performed by the authors. Statistical analysis of plasma level curves of omeprazole indicated that food induces a delay of the time of maximum concentrations, but had a lower effect on maximum concentration and area under curves. Peak areas of lansoprazole were not constant, presenting a similar pattern in all seven periods of the clinical experiment, both in feeding and fasting conditions: an increase after the standard meal at four hours from the administration of drug followed by relatively constant, but higher areas afterwards. Statistical analysis of data (1500 points) in the 3 - 6 h interval, i.e. from immediately before until two hours after food intake revealed a two phase effect: an initial decrease of areas followed by an increase to a higher level than in the preprandial conditions, leading to the appearance of a minimum in curves one hour after food intake. In almost all cases a good parabolic fitting of data was obtained, which is in agreement with authors previous results on extraction of ketoconazole from pasma in methylene chloride in the presence of bile salts. The increase of peak areas of lansoprazole from two hours after meal by 24 h lead to an artificial decrease of calculated omeprazole concentrations. This effect could explain the unexpected lack of food effect on the area under curve of omeprazole, observed in the comparison between areas in fasting and fed conditions.

scholarly journals Quantitative Analysis of Sulpiride and Impurities of 2-Aminomethyl-1-Ethylpyrrolidine and Methyl-5-Sulphamoyl-2-Methoxybenzoate in Pharmaceuticals by High-Performance Thin-Layer Chromatography and Scanning Densitometry

1999 ◽  
Vol 82 (4) ◽  
pp. 825-829 ◽  
Author(s):  
Danica Agbaba ◽  
Tatjana Miljkovic ◽  
Valentina Marinkovic ◽  
Dobrila Zivanov-Stakic ◽  
Sote Vladimirov
Keyword(s):  
Quantitative Analysis ◽  
Thin Layer ◽  
High Performance ◽  
Methylene Chloride ◽  
Solvent System ◽  
Ammonia Solution ◽  
Dosage Forms ◽  
Raw Material ◽  
Layer Chromatography

Abstract A simple and reliable thin-layer chromatographic method for determining sulpiride and impurities of 2-aminomethyl-1-ethylpyrrolidine and methyl-5-sulphamoyl-2-methoxybenzoate was developed and validated. A methylene chloride–methanol–ammonia solution (25%; 18 + 2.8 + 0.4, v/v) solvent system is used for separation and quantitative evaluation of chromatograms. The chromatographic plate is first scanned at 240 nm to locate chromatographic zones corresponding to sulpiride and methyl-5-sulphamoyl-2-methoxybenzoate. Then 2-aminomethyl-1-ethylpyrrolidine is derivatized in situ with ninhydrin, and resulting colored spots are measured at 500 nm. The method is reproducible and convenient for quantitative analysis and purity control of sulpiride in its raw material and in its dosage forms.

An Efficient Strategy Based on Liquid–Liquid Extraction With Acid Condition and HSCCC for Rapid Enrichment and Preparative Separation of Three Caffeoylquinic Acid Isomers From Mulberry Leaves

2019 ◽  
Vol 57 (8) ◽  
pp. 738-744 ◽  
Author(s):  
Li-Tao Wang ◽  
Ming-Zhu Gao ◽  
Qing Yang ◽  
Qi Cui ◽  
Yue Jian ◽  
...  
Keyword(s):  
High Speed ◽  
Solvent System ◽  
Macroporous Resin ◽  
Acid Condition ◽  
Two Phase ◽  
Caffeoylquinic Acids ◽  
Mulberry Leaves ◽  
Caffeoylquinic Acid ◽  
Liquid Liquid Extraction ◽  
Separation Strategy

Abstract Morus alba L. is a medicinal plant that contains a high amount of caffeoylquinic acids such as 3-caffeoylquinic acid (3-CQA), 5-caffeoylquinic acid (5-CQA) and 4-caffeoylquinic acid (4-CQA). This study aimed to establish a fast and efficient method for separating caffeoylquinic acids from mulberry leaves by using high-speed countercurrent chromatography coupled with macroporous resin. D101 resin showed better adsorption and desorption capacity for three caffeoylquinic acids among six macroporous resin adsorbents. The contents of 3-CQA, 5-CQA and 4-CQA reached for 4.77%, 18.95% and 9.84% through one cycle of D101 resin, which were 3.13-fold, 4.57-fold and 4.78-fold more than those in crude extracts, respectively. With a two-phase solvent system of ethyl acetate-water (1:1, V/V), >93% purity of target compounds were obtained in one cycle during 150 min with the recovery yields of 80.59%, 99.56% and 94.21% for 3-CQA, 5-CQA and 4-CQA, respectively. The structural identification of target compounds was carried out by ESI-MS, 1H NMR and 13C NMR spectra. The present result represented an easy and efficient separation strategy for the utilization of mulberry resource.

scholarly journals Quality Control of Psoralea corylifolia L. Based on High-Speed Countercurrent Chromatographic Fingerprinting

Molecules ◽  
2020 ◽  
Vol 25 (2) ◽  
pp. 279
Author(s):  
Xiaoxue Wu ◽  
Xuemin Gao ◽  
Xinmei Liu ◽  
Shuyi Zhang ◽  
Huayu Yang ◽  
...  
Keyword(s):  
Quality Control ◽  
High Speed ◽  
Solvent System ◽  
Chemical Components ◽  
Therapeutic Effects ◽  
Psoralea Corylifolia ◽  
Good Separation ◽  
Two Phase ◽  
Plant Materials

Traditional Chinese medicine (TCM)has played an important role in promoting the health of Chinese people. The TCM Psoralea corylifolia L. has been used in the treatment of various kinds of diseases including enuresis, vitiligo, and calvities. However, therapeutic effects of P. corylifolia L. have often influenced by the quality of plants. So, it is very important to control the quality of P. corylifolia L. In this study, analytical high-speed countercurrent chromatography (HSCCC) was successfully used to fingerprint P. corylifolia L. Samples of P. corylifolia L. were extracted by ultrasonic extraction. n-hexane-ethyl acetate–methanol–water at a ratio of 5:5.5:6.5:5 (v/v) was selected as a two-phase solvent system and the condition of HSCCC were optimized in order to good separation. And the method of HSCCC was verified (reproducibility, precision, and stability). HSCCC chromatograms exhibited six common peaks, which were selected as indicator compounds for the quality control of P. corylifolia L. Within 20 types of medicinal materials, chemical components are similar, but the levels of components are quite different in HSCCC fingerprint. The present results demonstrate that the HSCCC method provides a reliable basis for the quality control of P. corylifolia L. and can also be applied to confirm the authenticity of plant materials.

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