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Using the monomolecular film technique, we studied interfacial properties of Fusarium solani lipase (FSL). This lipolytic enzyme was found to be unique among the fungal lipases possessing not only a lipase activity but also a high phospholipase one.The FSL was able to hydrolyze dicaprin films at various surface pressures. The surface pressure dependency, the stereospecificity, and the regioselectivity...
A novel method to indicate the degree of chirality in polyaniline (PANI) was developed. The ( d‐camphorsulfonic acid)‐ and (HCl)‐PANI‐based electrodes exhibited significantly different electrochemical performances in d‐ and l‐Alanine (Ala) aqueous solution, respectively, which can be used for the characterization the optical activity of chiral PANI. Cyclic voltammogram, tafel, and open circuit potential...
(18‐Crown‐6)‐2,3,11,12‐tetracarboxylic acid is a useful chiral NMR solvating agent for isoxazoline‐fused β‐amino acid derivatives. Isoxazoline substrates are analyzed as their hydrochloride salts in methanol‐d4. The crown ether and substrate associate through the formation of three hydrogen bonds between the protonated amine and crown ether oxygen atoms. Enantiomeric discrimination is observed for...
A novel nickel(II) hexaaza macrocyclic complex, [Ni(LR,R)](ClO4)2 (1), containing chiral pendant groups was synthesized by an efficient one‐pot template condensation and characterized (LR,R═1,8‐di((R)‐α‐methylnaphthyl)‐1,3,6,8,10,13‐hexaazacyclotetradecane). The crystal structure of compound 1 was determined by single‐crystal X‐ray analysis. The complex was found to have a square‐planar coordination...
(1R)‐Normetanephrine is the natural stereoisomeric substrate for sulfotransferase 1A3 (SULT1A3)‐catalyzed sulfonation. Nothing appears known on the enantioselectivity of the reaction despite its potential significance in the metabolism of adrenergic amines and in clinical biochemistry. We confronted the kinetic parameters of the sulfoconjugation of synthetic (1R)‐normetanephrine and (1S)‐normetanephrine...
l‐ and d‐amino acids have diverse functions and effects on the metabolism, growth, and development of plants. Ornithine (Orn) plays a main role in the biosynthesis of many amino acids, nicotinic alkaloids, and polyamines in tobacco. This investigation describes the impact of Orn enantiomers on the production and distribution of free, conjugated, and bound polyamines, as well as nicotine in tobacco...
Tetrahydropalmatine (THP), with one chiral center, is an alkaloid that possesses analgesic and many other pharmacological actives. The aim of the present study is to investigate stereoselective metabolism of THP enantiomers in human liver microsomes (HLM) and elucidate which cytochrome P450 (CYP) isoforms contribute to the stereoselective metabolism in HLM. Additionally, the inhibitions of THP enantiomers...
Metoprolol is available for clinical use as a racemic mixture. The S‐(−)‐metoprolol enantiomer is the one expressing higher activity in the blockade of the β1‐adrenergic receptor. The α‐hydroxymetoprolol metabolite also has activity in the blockade of the β1‐adrenergic receptor. The present study describes the development and validation of a stereoselective method for sequential analysis of metoprolol...
The salt and stereoselective cocrystal phenomena associated with 2‐phenylglycinol and 2‐phenylglycine have been studied using X‐ray powder diffraction and differential scanning calorimetry. The chiral identities of the free acids and their sodium salts, or the free bases and their chloride salts, were found to play a determining role as to whether a salt–cocrystal product could or could not be formed...
A theoretical investigation of the photochemistry of racemic compounds with circularly polarized light was undertaken. The exact solutions of the differential equations by numerical integration to the approximate solutions used in an earlier article were compared. The exact solutions showed that sequential reactions yield enhanced optical activities in the products. For irreversible reactions, all...
The ability of chiral β‐amino alcohols to catalyze the direct asymmetric aldol reaction was evaluated for the first time in aqueous micellar media. A family of cheap and easily accessible β‐amino alcohols, obtained in one step from naturally occurring amino acids, was shown to successfully catalyze the asymmetric aldol reaction between a series of ketones and aromatic aldehydes. These aldol reactions...
The enantiomers of ketoprofen were separated by capillary electrophoresis using the (2,3,6‐tri‐O‐methyl)‐derivatives of α‐, β‐, and γ‐cyclodextrin (CyD) as chiral selectors. The affinity pattern of the ketoprofen enantiomers toward these CyDs changed depending on their cavity size. Thus, with hexakis (2,3,6‐tri‐O‐methyl)‐α‐CyD and heptakis (2,3,6‐tri‐O‐methyl)‐β‐CyD, the R enantiomer of the drug migrated...
Templated self‐sorting on surfaces has been introduced recently as a new approach to construct multicomponent architectures directly on solid oxide surfaces. In this process, two‐dimensional information placed on the surface is transcribed into three‐dimensional architectures with up to 97% intrinsic templation efficiency. Previously, we have shown that isosteric partners of different color do neither...
Stochastic and potentiometric microsensors based on porphyrins and polymeric surfactants such as polysodium N‐undecanoyl‐ l‐leucylvanilate and polysodium N‐undecanoyl‐ l‐vanilate were developed for enantioselective assay of pipecolic acid. The matrices used for the design of the stochastic sensors were diamond paste and graphite paste, while the matrix used for the design of potentiometric sensors...
The resolution of seven enantiomeric pairs of chiral derivatives of xanthones (CDXs) on (S,S)‐Whelk‐O1 and l‐phenylglycine chiral stationary phases (CSPs) was systematically investigated using multimodal elution conditions (normal‐phase, polar‐organic, and reversed‐phase). The (S,S)‐Whelk‐O1 CSP, under polar‐organic conditions, demonstrated a very good power of resolution for the CDXs possessing an...
Four known hydroxyanthraquinones (1–4) together with four new derivatives having a tetralone moiety, namely coniothyrinones A–D (5–8), were isolated from the culture of Coniothyrium sp., an endophytic fungus isolated from Salsola oppostifolia from Gomera in the Canary Islands. The structures of the new compounds were elucidated by detailed spectroscopic analysis and comparison with reported data....
We investigated the stereodynamics of 5,5’‐substituted tropos BIPHEP ligands (2,2’‐bis(diphenylphosphino)‐biphenyls) by enantioselective dynamic high‐performance liquid chromatography (DHPLC) to elucidate the influence of the substitution pattern and electronics of the substituents (methyl, methoxy, and hydroxyl groups). By temperature‐dependent dynamic HPLC measurements the activation parameters...
Phytotoxins are secondary microbial metabolites that play an essential role in the development of disease symptoms induced by fungi on host plants. Although phytotoxins can cause extensive—and in some cases devastating—damage to agricultural crops, they can also represent an important tool to develop natural herbicides when produced by fungi and plants to inhibit the growth and spread of weeds. An...
High performance liquid chromatography (HPLC) and capillary electrophoresis (CE) were used to examine the enantiomeric separation of a series of 17 racemic tetrahydrobenzimidazole analytes. These compounds were prepared as part of a synthetic program directed towards a select group of pyrrole‐imidazole alkaloids. This group of natural products has a unique framework of pyrrole‐ and guanidine‐containing...
Four groups of organophosphonate derivatives enantiomers were separated on N‐(3,5‐dinitrobenzoyl)‐S‐leucine chiral stationary phase. The three‐dimensional structures of the complexes between the single enantiotopic chiral compounds and chiral stationary phase have been studied using molecular model and molecular dynamics simulation. Detailed results regarding the conformation, auto‐docking, and thermodynamic...
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