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Molecules ◽  
2021 ◽  
Vol 26 (22) ◽  
pp. 6873
Author(s):  
Elżbieta Łastawiecka ◽  
Adam Włodarczyk ◽  
Anna E. Kozioł ◽  
Hanna Małuszyńska ◽  
Kazimierz Michał Pietrusiewicz

The resolution of racemic 1-phenylphosphin-2-en-4-one 1-oxide (2), was achieved through the fractional crystallization of its diastereomeric complexes with (4R,5R)-(−)-2,2-dimethyl -α,α,α′,α′-tetraphenyl-dioxolan-4,5-dimethanol (R,R-TADDOL) followed by the liberation of the individual enantiomers of 2 by flash chromatography on silica gel columns. The resolution process furnished the two enantiomers of 2 of 99.1 and 99.9% e.e. at isolated yields of 62 and 59% (counted for the single enantiomer), respectively. The absolute configurations of the two enantiomers were established by means of X-ray crystallography of their diastereomerically pure complexes, i.e., (R)-2•R,R)-TADDOL and (S)-2•(R,R)-TADDOL. The structural analysis revealed that in the (R)-2•(R,R)-TADDOL complex, the P-phenyl substituent occupied a pseudoequatorial position, whereas in (S)-2•(R,R)-TADDOL, it appeared in both the pseudoequatorial and the pseudoaxial positions in four symmetrically independent molecules. Concurrent conformational changes of the TADDOL molecules were best described by the observed changes of a pseudo-torsional CO...OC angle that could be considered as a possible measure of TADDOL conformation in its receptor–ligand complexes. The structural analysis of the (R,R)-TADDOL molecule revealed that efficiency of this compound for use as an effective resolving factor comes from its ability to flexibly fit its structure to both enantiomers of a ligand molecule, producing a rare case of resolution for both pure enantiomers with one chiral separating agent. The resolved (R)-2 was used to assign the absolute configuration of a recently described (−)-1-phenylphosphin-2-en-4-one 1-sulfide by chemical correlation. In addition, an attempted stereoretentive reduction of (R)-2 by PhSiH3 at 60 °C revealed an unexpectedly low barrier for P-inversion in 1-phenylphosphin-2-en-4-one.


Molecules ◽  
2021 ◽  
Vol 26 (21) ◽  
pp. 6589
Author(s):  
Roman Labuda ◽  
Markus Bacher ◽  
Hannes Gratzl ◽  
Maria Doppler ◽  
Alexandra Parich ◽  
...  

In the process of screening for new bioactive microbial metabolites we found a novel ƴ-pyrone derivative for which we propose the trivial name luteapyrone, in a recently described microscopic filamentous fungus, Metapochonia lutea BiMM-F96/DF4. The compound was isolated from the culture extract of the fungus grown on modified yeast extract sucrose medium by means of flash chromatography followed by preparative HPLC. The chemical structure was elucidated by NMR and LC-MS. The new compound was found to be non-cytotoxic against three mammalian cell lines (HEK 263, KB-3.1 and Caco-2). Similarly, no antimicrobial activity was observed in tested microorganisms (gram positive and negative bacteria, yeast and fungi).


Author(s):  
Smriti Rekha Chanda Das ◽  
Abdul Baquee Ahmed ◽  
Dibyendu Shil ◽  
Trishna Das ◽  
Faruk Alam ◽  
...  

Aim: The present study was aimed to establish antifungal activity of flavonoid isolated from Lindernia crustacea (L) F. Muell. Methods: Potent bioactive constituent from benzene extract was isolated through flash chromatography with solvent Toluene and Acetic acid (4:1). Isolated compound was structurally established by spectroscopic method. Antifungal potential of benzene extract as well as isolated compound was tested by disc diffusion method against two fungal strains Candida albicans (C. albicans) and Trichophyton rubrum (T. rubrum). Results: The isolated compound from benzene extract was found to be flavonoid. Benzene extract as well as flavonoid were shown remarkable zone of inhibition against both fungal strains which indicates strong antifungal activity. Conclusion: The experimental results concluded that Lindernia crustacea (L) F. Muell have significant anti fungal activity due to flavonoid content. It is expected that the results of the present research work would be beneficial in establishing the scientific basis of the traditional claims of medicinal values of Lindernia crustacea.


2021 ◽  
Vol 12 (4) ◽  
pp. 5647-5662

Today, emerging infectious diseases caused by multidrug-resistant bacteria (MDRB) are a major public health problem. These bacteria are gradually becoming more resistant to conventional antimicrobial agents. Thus, there is an urgent requirement to explore new antimicrobial compounds. This study focuses on a screening program of marine actinobacteria for useful bioactive compounds against MDRB, and four endophytic actinobacteria strain isolated from the unexploited marine brown alga Carpodesmia tamariscifolia, harvested from the Atlantic coast of Morocco, were screened for their antimicrobial activities using the agar diffusion assay. Fermentation broths of the two selected promising isolates KC179 and KC180 were extracted with different organic solvents and showed antibacterial activity against methicillin-resistant Staphylococcus aureus, Acinetobacter baumannii, and Pseudomonas aeruginosa. From the butanolic extract of KC180's culture broth and in addition to the known metabolite desferrioxamine B, a new desferrioxamine derivative, desferrioxamine B2, was purified using flash chromatography and reversed-phase HPLC, and its structure was elucidated using HRMS and NMR spectroscopy. The 16S rRNA molecular taxonomic characterization of the producing strain KC180 showed Streptomyces albidoflavus as the nearest relative, with a sequence similarity of 99.71 %.


Molecules ◽  
2021 ◽  
Vol 26 (19) ◽  
pp. 6008
Author(s):  
Chad Normandin ◽  
Pierre-Luc Boudreault

Tomatidine has recently generated a lot of interest amongst the pharmacology, medicine, and biology fields of study, especially for its newfound activity as an antibiotic agent capable of targeting multiple strains of bacteria. In the light of its low natural abundance and high cost, an efficient and scalable multi-gram synthesis of tomatidine has been developed. This synthesis uses a Suzuki–Miyaura-type coupling reaction as a key step to graft an enantiopure F-ring side chain to the steroidal scaffold of the natural product, which was accessible from low-cost and commercially available diosgenin. A Lewis acid-mediated spiroketal opening followed by an azide substitution and reduction sequence is employed to generate the spiroaminoketal motif of the natural product. Overall, this synthesis produced 5.2 g in a single pass in 15 total steps and 15.2% yield using a methodology that is atom economical, scalable, and requires no flash chromatography purifications.


Author(s):  
Jessica Jung ◽  
Lars Kaiser ◽  
Hans-Peter Deigner ◽  
Magnus S. Schmidt

Abstract In this study, bromoalkyl glycosides were successfully synthesized in microreactor scale by Fischer glycosylation. Yields between 24 and 40% after purification were achieved using various acidic catalysts and conditions. In some experiments, yields 180% higher than with previously known methods could be achieved. This study showed also that reversed-phase flash chromatography is more successful than normal-phase flash chromatography for the purification of bromoalkyl glycosides. Furthermore, longer bromoalcohols were shown to be more compatible than shorter bromoalcohols under these reaction conditions.


Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 4810
Author(s):  
Gabin Thierry M. Bitchagno ◽  
Jean Garba Koffi ◽  
Ingrid Konga Simo ◽  
Donald Ulrich K. Kagho ◽  
Augustin Silvere Ngouela ◽  
...  

A total of nine sesquiterpenoid lactones together with phenolic compounds and other terpenes were identified from the crude methanol extract of Elephantopus mollis Kunth. Compounds were isolated using different chromatographic techniques and their structures were determined by NMR and IR spectroscopy as well as mass spectrometry. The structures of some detected compounds were assigned based on LC-ToF-ESI-MS screening of main fractions/subfractions from flash chromatography and comparison with isolated analogues as standards. The findings revealed not only the in-source loss of water as the base peak in hirsutinolides but also the in-source loss of corresponding alcohol when the oxygen at position 1 is alkylated. The present study also draws up a complement of data with respect to hirsutinolide-like sesquiterpene lactones whose LC-MS characteristics are not available in the literature. The chemophenetic significance is also discussed. Some of the isolated compounds were reported for the first time to be found in the species, the genus as well as the plant family. The medium-polar fractions of the crude extract, also containing the larger amount of sesquiterpenoid lactones, exhibited activity both against a cancer cell line and bacterial strains. Isolated lactones were also active against the cancer cell line, while the chlorogenic derivatives also valuable in Elephantopus genus showed potent radical scavenging activity. This is the first report of cytotoxic and antibacterial activities of our samples against the tested strains and cell line. The present study follows the ongoing research project dealing with the characterization of taxa with antibacterial and antiparasitic activities from Cameroonian pharmacopeia.


Synlett ◽  
2021 ◽  
Author(s):  
Thomas C. Pickel ◽  
Nathan E. Genung ◽  
Kevin M. Guckian ◽  
Xianglin Shi

AbstractA simple, cost effective, and readily accessible apparatus for the photoisomerization of cis-cyclooctenes to trans-cyclooctenes is described. Utilizing only FEP tubing, aluminum vent pipe, a household germicidal lamp, and a flash chromatography system, trans-cyclooctenes can be prepared in good yield.


Author(s):  
Christopher G. Thomson ◽  
Colin Banks ◽  
Mark Allen ◽  
Graeme Barker ◽  
Christopher R. Coxon ◽  
...  

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3785
Author(s):  
Sleman Kadan ◽  
Sarit Melamed ◽  
Shoshana Benvalid ◽  
Zipora Tietel ◽  
Yoel Sasson ◽  
...  

Type 2 diabetes (T2D) is a chronic metabolic disease, which could affect the daily life of patients and increase their risk of developing other diseases. Synthetic anti-diabetic drugs usually show severe side effects. In the last few decades, plant-derived drugs have been intensively studied, particularly because of a rapid development of the instruments used in analytical chemistry. We tested the efficacy of Gundelia tournefortii L. (GT) in increasing the translocation of glucose transporter-4 (GLUT4) to the myocyte plasma membrane (PM), as a main strategy to manage T2D. In this study, GT methanol extract was sub-fractionated into 10 samples using flash chromatography. The toxicity of the fractions on L6 muscle cells, stably expressing GLUTmyc, was evaluated using the MTT assay. The efficacy with which GLUT4 was attached to the L6 PM was evaluated at non-toxic concentrations. Fraction 6 was the most effective, as it stimulated GLUT4 translocation in the absence and presence of insulin, 3.5 and 5.2 times (at 250 μg/mL), respectively. Fraction 1 and 3 showed no significant effects on GLUT4 translocation, while other fractions increased GLUT4 translocation up to 2.0 times. Gas chromatography–mass spectrometry of silylated fractions revealed 98 distinct compounds. Among those compounds, 25 were considered anti-diabetic and glucose disposal agents. These findings suggest that GT methanol sub-fractions exert an anti-diabetic effect by modulating GLUT4 translocation in L6 muscle cells, and indicate the potential of GT extracts as novel therapeutic agents for T2D.


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