scholarly journals Phosphonates enantiomers receiving with fungal enzymatic systems

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Monika Serafin-Lewańczuk ◽  
Małgorzata Brzezińska-Rodak ◽  
Katarzyna Lubiak-Kozłowska ◽  
Paulina Majewska ◽  
Magdalena Klimek-Ochab ◽  
...  
Keyword(s):  
Kinetic Resolution ◽  
Nutrient Deficiency ◽  
Methylphosphonic Acid ◽  
Racemic Mixture ◽  
Biological Interactions ◽  
Racemic Mixtures ◽  
Enzymatic Systems ◽  
Pre Treatment ◽  
Physical Features ◽  
First Time

Abstract Background Phosphonates derivatives are in the area of interests because of their unique chemical-physical features. These compounds manifest variety of biological interactions within the sensitive living cells, including impact on particular enzymes activities. Biological “cause and effect” interactions are based upon the specific matching between the structures and/or compounds and this is usually the result of proper optical configurations of particular chiral moieties. Presented research is targeted to the phosphonates with the heteroatom incorporated in their side functionalities. Such molecules are described as possible substrates of bioconversion for the first time lately and this field is not fully explored. Results Presented research is targeted to the synthesis of pure hetero-phosphonates enantiomers. The catalytic activity of yeasts and moulds were tested towards two substrates: the thienyl and imidazole phosphonates to resolve their racemic mixtures. Biotransformations conditions differed depending on the outcome, what included changing of following parameters: type of cultivation media, bioprocess duration (24–72 h), additional biocatalyst pre-treatment (24–48 h starvation step triggering the secondary metabolism). (S)-1-amino-1-(3-thienyl)methylphosphonate was produced with the assistance of R. mucilaginosa or A. niger (e.e. up to 98% and yield up to 100%), starting from the 3 mM of substrate racemic mixture. Bioconversion of racemic mixture of 3 mM of (1-amino-1-(4-imidazole)methylphosphonic acid) resulted in the synthesis of S-isomer (up to 95% of e.e.; 100% of yield) with assistance of R. mucilaginosa. 24 h biotransformation was conducted with biomass preincubated under 48-hour starvation conditions. Such stereoselective resolution of the racemic mixtures of substrates undergoes under kinetic control with the conversion of one from the enantiomers. Conclusions Composition of the culturing media and pre-incubation in conditions of nutrient deficiency were significant factors influencing the results of kinetic resolution of racemic mixtures of phosphonic substrates and influencing the economic side of the biocatalysis e.g. by determining the duration of whole biocatalytic process. Graphical abstract

scholarly journals Analysis of Accessibility to Family Health Centers in Antalya Using GIS

2022 ◽  
Vol 9 (sp) ◽  
pp. 2442-2448
Author(s):  
Orhun Soydan
Keyword(s):  
Social Ties ◽  
Family Health ◽  
Point Of View ◽  
Health Centers ◽  
Walking Distance ◽  
Physical Conditions ◽  
The Social ◽  
The Subject ◽  
Physical Features ◽  
First Time

Family health centers in Turkey started to be implemented for the first time in Düzce in 2004 years within the scope of Law No. 5258. While determining the physical conditions of the places where family health centers are built, the first item in the regulation is that the building should be easily accessible. This situation shows the importance of the subject in terms of accessibility. While determining the features of the places where FHCs will be made, environmental characteristics are also taken into consideration. Environmental features are effective in determining the FHCs location in different ways. These impacts are divided into two groups: the physical features that pavements, roads and parks can include, and the social, cultural and institutional features of neighborhoods that include local social ties and collective activities. From this point of view, the importance of the location of family health centers relative to roads and houses is understood. The aim of this study is to examine the accessibility of Family Health Centers in Konyaaltı, Antalya, on a neighborhood basis using Geographic Information Systems. Konyaaltı has 21 Family Health Centers. As a result of the analyses, it was determined that most of the neighborhoods had problems in terms of accessibility, while a very few of them did not experience problems in terms of accessibility. In terms of the total number of buildings, the ratio of buildings that are 500 meters walking distance from any family health center by using highways is 35.56%. With these rates, 3,634 of the 10,2018 buildings remain within the limits of the regulation. Finally; suggestions were made to increase accessibility to these areas.

scholarly journals Recent Approaches to Chiral 1,4-Dihydropyridines and their Fused Analogues

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1019
Author(s):  
Martins Rucins ◽  
Aiva Plotniece ◽  
Eiva Bernotiene ◽  
Wei-Bor Tsai ◽  
Arkadij Sobolev
Keyword(s):  
Kinetic Resolution ◽  
Stereoselective Synthesis ◽  
Biological Activities ◽  
Great Promise ◽  
Racemic Mixtures ◽  
Treatment Of Hypertension ◽  
Opposite Action ◽  
Recent Developments ◽  
Substantial Progress ◽  
Active Calcium

The purpose of this review is to highlight recent developments in the synthesis of chiral 1,4-dihydropyridines and their fused analogues. 1,4-Dihydropyridines are among the most active calcium antagonists that are used for the treatment of hypertension. Enantiomers of unsymmetrical 1,4-dihydropyridines often show different biological activities and may have even an opposite action profile. Hantzsch synthesis usually produces racemic mixtures of unsymmetrical 1,4-dihydropyridines. Therefore, the development of stereoselective synthesis of 1,4-dihydropyridines is one of the priorities of medicinal chemistry. Over the years, numerous methodologies have been developed for the production of enantiopure 1,4-dihydropyridines, such as stereoselective synthesis using chiral auxiliaries and chiral cyclocondensation partners, chromatographical methods, resolution of diastereomeric 1,4-dihydropyridine salts, enzyme catalysed kinetic resolution, or asymmetrisation of ester groups of 1,4-dihydropyridines. These approaches have been studied in detail and are relatively well established. The catalytic asymmetric approach holds the greatest promise in delivering the most practical and widely applicable methods. Substantial progress has been made toward the development of enantioselective organocatalytic methods for the construction of the chiral dihydropyridines. However, most of them do not provide a convenient way to pharmacologically important 1,4-dihydropyridine-3,5-dicarboxylates. Organocatalytic enantioselective desymmetrisation of prochiral 1,4-dihydropyridine-3,5-dicarbaldehydes also has great promise in the synthesis of pharmacologically important 1,4-dihydropyridine-3,5-dicarboxylates.

scholarly journals Enantioselective Transesterification of Allyl Alcohols with (E)-4-Arylbut-3-en-2-ol Motif by Immobilized Lecitase™ Ultra

Catalysts ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 798
Author(s):  
Aleksandra Leśniarek ◽  
Anna Chojnacka ◽  
Radosław Drozd ◽  
Magdalena Szymańska ◽  
Witold Gładkowski
Keyword(s):  
High Activity ◽  
Cyanogen Bromide ◽  
Kinetic Resolution ◽  
Negative Effects ◽  
Subsequent Reaction ◽  
Wide Range ◽  
Allyl Alcohols ◽  
Reaction Cycles ◽  
Acyl Donors ◽  
First Time

Lecitase™ Ultra was immobilized on four different supports and tested for the first time as the biocatalyst in the kinetic resolution of racemic allyl alcohols with the (E)-4-arylbut-3-en-2-ol system in the process of transesterification. The most effective biocatalyst turned out to be the enzyme immobilized on agarose activated with cyanogen bromide (LU-CNBr). The best results (E > 200, ees and eep = 95–99%) were obtained for (E)-4-phenylbut-3-en-2-ol and its analog with a 2,5-dimethylphenyl ring whereas the lowest ee of kinetic resolution products (90%) was achieved for the substrate with a 4-methoxyphenyl substituent. For all substrates, (R)-enantiomers were esterified faster than their (S)-antipodes. The results showed that LU-CNBr is a versatile biocatalyst, showing high activity and enantioselectivity in a wide range of organic solvents in the presence of commonly used acyl donors. High operational stability of LU-CNBr allows it to be reused in three subsequent reaction cycles without negative effects on the efficiency and enantioselectivity of transesterification. This biocatalyst can become attractive to the commercial lipases in the process of the kinetic resolution of allyl alcohols.

Development and Validation of a Reversed-Phase Chiral HPLC Method to Determine the Chiral Purity of Bulk Batches of (S)-Enantiomer in Afoxolaner

2017 ◽  
Vol 100 (1) ◽  
pp. 65-73
Author(s):  
Nilusha Padivitage ◽  
Satish Kumar ◽  
Abu Rustum
Keyword(s):  
Method Development ◽  
Specific Rotation ◽  
Reversed Phase ◽  
Hplc Method ◽  
Racemic Mixture ◽  
Chiral Hplc ◽  
Development Tool ◽  
Chiral Purity ◽  
Development And Validation ◽  
First Time

Abstract Afoxolaner is a new antiparasitic molecule from the isoxazoline family that acts on insect acarine g-aminobutyric acid and glutamate receptors. Afoxolaner is a racemic mixture, which has a chiral center at the isoxazoline ring. A reversed-phase chiral HPLC method has been developed to determine the chiral purity of bulk batches of (S)-enantiomer in afoxolaner for the first time. This method can also be used to verifythat afoxolaner is a racemic mixture, which was demonstrated by specific rotation. ChromSword, an artificial intelligence method development tool, was used for initial method development. The column selected for the final method was CHIRALPAK AD-RH (150 × 4.6 mm, 5 μm particle size), maintained at 45°C, and isocratic elution using water–isopropanol–acetonitrile (40 + 50 + 10, v/v/v) as the mobile phasewith a detection wavelength of 312 nm. The run time for the method was 11 min. The resolution and selectivity factors of the two enantiomers were 2.3 and 1.24, respectively. LOQ and LOD of the method were 1.6 and 0.8 μg/mL, respectively. This method was appropriately validated according to International Conference on Harmonization guidelines for its intended use.

scholarly journals Capnophilic Lactic Fermentation from Thermotoga neapolitana: A Resourceful Pathway to Obtain Almost Enantiopure L-lactic Acid

Fermentation ◽  
2019 ◽  
Vol 5 (2) ◽  
pp. 34 ◽  
Author(s):  
Genoveffa Nuzzo ◽  
Simone Landi ◽  
Nunzia Esercizio ◽  
Emiliano Manzo ◽  
Angelo Fontana ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Enantiomeric Excess ◽  
Thermophilic Bacterium ◽  
Racemic Mixture ◽  
Thermotoga Neapolitana ◽  
High Concentration ◽  
Lactic Fermentation ◽  
Bacterial Fermentation ◽  
First Time

The industrial production of lactic acid (LA) is mainly based on bacterial fermentation. This process can result in enantiopure or racemic mixture according to the producing organism. Between the enantiomers, L-lactic acid shows superior market value. Recently, we reported a novel anaplerotic pathway called capnophilic lactic fermentation (CLF) that produces a high concentration of LA by fermentation of sugar in the anaerobic thermophilic bacterium Thermotoga neapolitana. The aim of this work was the identification of the enantiomeric characterization of the LA produced by T. neapolitana and identification of the lactate dehydrogenase in T. neapolitana (TnLDH) and related bacteria of the order Thermotogales. Chemical derivatization and GC/MS analysis were applied to define the stereochemistry of LA from T. neapolitana. A bioinformatics study on TnLDH was carried out for the characterization of the enzyme. Chemical analysis showed a 95.2% enantiomeric excess of L-LA produced by T. neapolitana. A phylogenetic approach clearly clustered the TnLDH together with the L-LDH from lactic acid bacteria. We report for the first time that T. neapolitana is able to produce almost enantiopure L-lactic acid. The result was confirmed by bioinformatics analysis on TnLDH, which is a member of the L-LDH sub-family.

Biocatalyzed kinetic resolution of racemic mixtures of chiral α-aminophosphonic acids

2013 ◽  
Vol 91 ◽  
pp. 32-36 ◽  
Author(s):  
Kinga Kozyra ◽  
Małgorzata Brzezińska-Rodak ◽  
Magdalena Klimek-Ochab ◽  
Ewa Żymańczyk-Duda
Keyword(s):  
Kinetic Resolution ◽  
Aminophosphonic Acids ◽  
Racemic Mixtures

scholarly journals Synthesis of trinorbornane

2017 ◽  
Vol 53 (83) ◽  
pp. 11399-11402 ◽  
Author(s):  
Lorenzo Delarue Bizzini ◽  
Thomas Müntener ◽  
Daniel Häussinger ◽  
Markus Neuburger ◽  
Marcel Mayor
Keyword(s):  
Racemic Mixture ◽  
Symmetric Structure ◽  
First Time

The tetracyclic, chiral, and C2-symmetric structure of trinorbornane (tetracyclo[5.2.2.01,6.04,9]undecane) is synthesized for the first time as a racemic mixture.

Fisher information and Shannon entropy calculations for two-electron systems

2020 ◽  
Vol 98 (8) ◽  
pp. 784-789 ◽  
Author(s):  
Ibraheem Nasser ◽  
Afaf Abdel-Hady
Keyword(s):  
Fisher Information ◽  
Yukawa Potential ◽  
Shannon Information ◽  
Electron Systems ◽  
Charge Densities ◽  
Screening Parameter ◽  
Information Products ◽  
Physical Features ◽  
First Time

Fisher information is calculated for the ground state of He-isoelectronic series, in position ([Formula: see text]) space. The results are given and discussed as a function of the nuclear charge (Z) and the screening parameter (λ) in the case study of Yukawa potential. Simple and explicit one-, two-, and three-correlated terms of Hylleraas wave function are used to focus on extracting the most characteristic physical features of the results. The numerical values of Fisher information are given in 1- and 2-electron charge densities, and their ratio of 2- to 1-electron densities results are defined and analyzed. To enable a comparison with others, the Fisher–Shannon information products, which measure the electron–electron correlation strength, are calculated in 1-electron density. The calculations of Fisher information, the ratio, and the Shannon-information products for two-electron systems in the presence of Yukawa potential are carried out for the first time in this study.

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