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AIM to determine the efficiency of different doses of erythropoietin and carbamylated darbepoetin, to prove experimentally the possibility of increasing the efficiency of carbamylated darbepoetin when using the levorotatory stereoisomer of ethoxidol. MATERIALS AND METHODS On the model of ischemia-reperfusion injury in male CD-1 mice that were undergone to contralateral nephrectomy, the nephroprotective effect of different doses of erythropoietin alfa, carbamylated darbepoetin, L-ethoxidol (the levorotatory enantiomer of ethylmethylhydroxypyridine malate), and the combined use of L-ethapylated carboxypyridine malate and L-etapoietin alfa was studied. The parameters of microcirculation and glomerular filtration rate were studied one day after 30-minute ischemia. RESULTS It has been established that the prophylactic use of erythropoietin alfa and carbamylated darbepoetin in the model of ischemia-reperfusion injury of a single kidney reduces the severity of microcirculatory impairment and ensures the preservation of the glomerular filtration rate in dose-dependent manner. The synergistic effect of L-ethoxidol and carbamylated darbepoetin was found when these substances were used together. CONCLUSION Prevention of ischemia-reperfusion kidney injury by analogs of human erythropoietin and their combination with ethylmethylhydroxypyridine derivatives is experimentally-proved.

With the simultaneous presence of positive and negative components both in the permittivity tensor ɛij and in the tensor of magnetic permeability μij, the propagation of an electromagnetic wave in optically homogeneous anisotropic media, and in periodically inhomogeneous media with a spiral structure is considered. It is shown that depending on polarization, such media exhibit the properties of both dextrorotatory and levorotatory substances. It is shown also that the medium with a spiral periodic structure may have the property of total diffraction reflection of the wave of any polarization. In the case of the presence of different signs of components of ɛij and μij in the spiral medium, it is revealed that two regions of diffraction reflection are formed, corresponding to the two waves with circular polarization with mutually opposite rotation of the polarization.

Aim. To study the cardioprotective effect of levorotatory ethylmethylhydroxypyridine malate enantiomer in combination with rosuvastatin on the model of doxorubicin cardiomyopathy.Material and methods. The research was conducted using 80 Langendorff perfused Wistar rat hearts (OOO “Kardioprotekt”, Saint-Petersburg) after a 3-day simulation of doxorubicin cardiomyopathy. The selection criteria for the evaluation of cardioprotective effect in the administration of ethylmethylhydroxypyridine derivatives and their combination with rosuvastatin were the indicators of left ventricular contractility, Tension-Time Index (t TTI), the diameter of cardiomyocytes.Results. During the experiment, it was found that the introduction of doxorubicin has a cardiotoxic effect, manifested through a decrease in the left ventricle contractility by 30–45% and an increase in the t TTI index by 4 times (“diastolic defect”). The introduction of a racemic mixture of ethylmethylhydroxypyridine malate at a dose of 93 mg/kg prevents the reduction of the left ventricle contractility and prevents the development of a “diastolic defect”, restraining the increase in the t TTI index by 32%, while the ethylmethylhydroxypyridine enantiomer at a dose of 93 mg/kg is more effective and its positive effect increases in combination with rosuvastatin at a dose of 0.4 mg/kg.Conclusion. The use of oxypyridine derivatives at doses of 50 mg/kg and 93 mg/kg, as well as their combination with rosuvastatin prevented the development of a “diastolic defect”. The highest effi ciency was revealed for the use of a combination of levorotatory ethylmethylhydroxypyridine malate enantiomer at a dose of 93 mg/kg with rosuvastatin at a dose of 0.4 mg/kg.

The exceptional case of a natural compound that shows drastic absolute configuration variations within the same species was examined. Sequential samples of areolal (1) isolated from Piptothrix areolare showed dextrorotatory (ee 32%), almost racemic (ee 4%), levorotatory (ee 82%), and again dextrorotatory (ee 10%) values. Enantiomeric compositions of this epoxythymol derivative were determined from individual plant specimens collected from the same geographical location over a 46-day period, which were processed using the same extraction and isolation methods. Detection of this unusual phenomenon was possible by analysis of NMR data recorded in the presence of BINOL as a chiral solvating agent. The absolute configuration of (-)-(8S)-areolal followed from vibrational circular dichroism data of an enantiomerically enriched sample, while single-crystal X-ray diffraction and supramolecular analyses revealed interactions that diminish the crystal entropy in rac-1. These results might be related with environmental factors and biochemical processes, suggesting the need of strict evaluations of enantiomeric composition of natural products that could be considered for human applications.

The new phthalideisoquinoline hemiacetal alkaloids (2-7) and the known analogues (1 and 8) were isolated from the bulbs of Corydalis decumbens. The new compounds were characterized by analysis of their NMR spectroscopic data, chemical degradation syntheses, X-ray crystallography, and comparison of experimental and calculated ECD data. All the isolates were screened in vitro for inhibitory activity of spontaneous calcium oscillations in primary cultured neocortical neurons. Compounds 1-3 and 5-7 were found to be active in the suppression of spontaneous calcium oscillations with IC50 values of 6.8, 5.6, 11.6, 10.2, 8.3, and 3.1 μM, respectively. It was also observed that the presence of hydroxy, methoxy, and ethoxy groups at the remote stereogenic center C-7' of some isolated phthalideisoquinoline hemiacetal alkaloids could alter the preferred conformation and invert the sign of optical rotation, rather than this resulting from configurational isomerism at C-1 or C-9, and that the 3J1,9 coupling constants of these analogues varied accordingly. For example, compounds 1 and 6 are levorotatory, despite these molecules having the same carbon skeleton and absolute configuration as (+)-egenine. This emphasizes the potential risk of incorrectly assigning absolute configuration based only on observed coupling constants or optical rotation when comparing the data of new compounds with literature values for known analogues, especially within this class of molecules.

The realization of chiral supramolecular architectures on solid surfaces has triggered much interest due to its potential enantiospecific applications. An in-depth study of chiral aggregation on surfaces is significant for developing functional chiral surfaces. Herein, we report thermally induced chiral aggregation of dihydrobenzopyrenone on Au(111). By high-resolution low-temperature scanning tunneling microscopy, a racemate monolayer consisting of levorotatory and dextrorotatory dihydrobenzopyrenones was found to aggregate into conglomerate domains after moderate annealing treatment. Combined with first-principles calculations, we suggest that the intermolecular dipole-dipole interaction plays an important role in chiral aggregation, which takes place via molecular in-plane diffusion rather than molecular out-of-plane flipping. This work unveils one underlying mechanism of thermally induced chiral aggregation, thus enabling potential applications such as fabricating supramolecular architectures for functional chiral surfaces.

The asymmetric Michael addition between propionaldehyde and nitroalkene catalyzed by 8-(ethoxycarbonyl)-1,2,3,3a,8,8a-hexahydropyrrolo[2,3-b]indole-2-carboxylic acid has obtained relatively high yields and excellent enantioselectivities at room temperature. In this study, the molecular structures and optical activity of the most stable conformation I are optimized at B3LYP/6-311++ G(d,p) level. We find that levorotatory conformation I catalyzing the same Michael addition can produce laevo-product A and dextrorotatory conformation I' can obtain the dextral-product A'. These results have guiding significance for further studying on the new chemzymes and the mechanism of the obtained different chiral products.

A new levorotatory compound ((S)-9,9′-(6-(1-phenylethoxy)-1,3,5-triazine-2,4-diyl)bis(9H-carbazole)) and its corresponding racemic compound show different intermolecular interactions to restrain nonradiative transition, resulting in an enhanced ultralong organic phosphorescence lifetime from 229.0 ms to 419.8 ms. This work will provide a new insight into the chirality of organic molecules to adjust the ultralong phosphorescence.

In the present work, molecular imprinting silica xerogel (MISX) with selective recognition function aiming to regulate drug therapy was synthesized using biomimetic method with poly(ethyleneimine)s (PEIs) as the polymer template and levorotatory ofloxacin (LOFL) as recognition template. Ultraviolet spectroscopy wavelength scanning was used to test the removal process of LOFL, and characteristics of selective loading ofloxacin (OFL) into MISX were investigated using Fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC). Molecular recognition functionality of MISX was intensively studied, including OFL loading and release. The results suggested that MISX possessed ability to recognize and selectively adsorb LOFL into MISX in OFL aqueous solution. Amorphous phase of adsorbed molecules contributed to molecular recognition because amorphous state increased the stability of LOFL that were selectively adsorbed into MISX, which induced stronger hydrogen bonding formed between LOFL and MISX so as to improve LOFL recognition ability. In vitro release revealed that OFL-MISX tablet initially released LOFL and later gradually OFL into dissolution medium. Thus conversion of drug release with different pharmacological activity had special value in delivering systems.

The proteins belonging to different organisms as well as the natural amino acids as incorporated into proteins occurring free in tissues and lymphatic fluids are, as a rule, levorotatory. This article contains a simple explanation of this structural discrimination and of the extremely slow racemization of natural organic substances.

The first enantioselective synthesis of furanditerpene ambliol-A, which is a major metabolite of marine sponge Dysidea amblia, has been accomplished by starting from racemic α-ionone. The key steps of the synthesis include lipase-mediated resolution of 4-hydroxy-γ-ionone, its stereoselective transformation into trans-α-epoxy-dihydroionone, C2 homologation to trans-α-epoxy-monocyclofarnesyl acetate and Li2CuCl4-catalysed sp3–sp3 cross-coupling reaction of the latter ester with (furan-3-ylmethyl)magnesium chloride. This work confirms the chemical structure previously assigned to ambliol-A and proves that the natural levorotatory isomer does not possess (1S,2S) absolute configuration, as previously indicated, but is the opposite enantiomer, (1R,2R)-2-[(E)-6-(furan-3-yl)-3-methylhex-3-enyl]-1,3,3-trimethylcyclohexanol.

Chiral catalytic activities of electrode surfaces fabricated by magnetoelectrochemical etching without oxygen adsorption in a vertical magnetohydrodynamic (MHD) flow have been theoretically examined. Then, the following points were clarified: under anionic specific adsorption, such activities arise from the screw dislocations of 2D pits. Their chirality is donated by microscopic vortexes termed micro-MHD flows, which are formed on the free surfaces covered with ionic vacancies. As a result, under upward (+) and downward (-) magnetic fields, D (dextrorotatory)- and L (levorotatory)-activities appear, respectively.

4,6-Disubstituted 2,2-dimethylchromans are reported as pharmacologically active compounds that mainly target the ATP-sensitive potassium channels. The present study is an attempt to characterize the impact of the nature of substituents introduced at the 4- and 6-positions of 2,2-dimethylchromans on their capacities to inhibit insulin release from pancreatic β-cells or to relax vascular smooth muscle cells, both biological responses that are supposed to reflect interaction with specific ion channels. From the core structure 4-amino-2,2-dimethylchroman, a progressive increase in the steric hindrance of the chemical functionalities introduced at the 4-position (amino, formamido, acetamido, arylureido/thioureido) and at the 6-position (amino, formamido, acetamido, alkoxycarbonylamino) led to a progressive magnification of the inhibitory effect on the insulin release process and, to a lesser extent, of the vasorelaxant activity. Moreover, the dextrorotatory enantiomer of 2,2-dimethylchroman compound 29 was more potent than its levorotatory counterpart for inhibiting the insulin secretory process. Additional pharmacological investigations suggested, however, that the myorelaxant activity of 11 and 15 resulted from a direct Ca2+ entry blockade.

A one-pot biomimetic synthesis of (−)-angiopterlactone B and its enantiomer (+)-angiopterlactone B has been accomplished via TBAF-catalyzed tandem ring contraction followed by oxa-Michael/Michael addition sequence. Comparison of specific optical rotations, absolute configurations, and CD spectra of natural, synthesized (−)-angiopterlactone B and (+)-angiopterlactone B unequivocally proves that the isolated angiopterlactone B must be levorotatory. Synthesis of hitherto undiscovered natural products 18 and 20 and analogues of angiopterlactone B demonstrate the versatility of this method.

A new procedure for the synthesis of optically active t-butylophenylphosphinothioic acid as an enantiomerically pure dextrorotatory enantiomer having the absolute configuration (R), by a reaction of the racemate of secondary t-butylphenylphosphine oxide with elemental sulfur in the presence of a molar equivalent of the levorotatory enantiomer of enantiomerically pure (S)-α-phenylethylamine, is reported. It is obvious that with the use of the dextrorotatory enantiomer of α-phenylethylamine, the levorotatory enantiomer of this thioacid will be isolated.

A facile selective method has been developed for the synthesis of new fluorine-containing cispentacin stereoisomers. Mono- and difluorinated cispentacin derivatives were synthetized from a bicyclic β-lactam in five or six steps involving a regio- and stereoselective hydroxylation through iodooxazoline formation, followed by deoxygenation by fluorination. Starting from an enantiomerically pure bicyclic β-lactam obtained by enzymatic resolution of the racemic compound, an enantiodivergent procedure allowed the preparation of both dextro- and levorotatory difluorinated cispentacins.

((−)-Menthyl (S)-6′-acrylyl-2′-methyloxy-1,1′-binaphthalene-2-carboxylate (3) was synthesized and anionically polymerized using n-BuLi as an initiator in toluene. The monomer 3 was levorotatory and had an [α]D25 value of −72.4, but its corresponding polymer poly-3 was dextrorotatory and showed an [α]D25 value of +162.0. Poly-3 was confirmed to exist in the form of one-handed helical structure in solution by means of comparing the specific optical rotation and the CD spectra with that of 3 and the model compounds such as (−)-menthyl (S)-6′-propionyl-2′-methyloxy-1,1′-binaphthalene-2-carboxylate 2b and (−)-menthyl (S)-6′-heptanoyl-2′-methyloxy-1,1′-binaphthalene-2-carboxylate 2c. This conclusion was also confirmed by the fact that the g-value of poly-3 is about 11 times of that of monomer 3.

The alkaloid (-)-tylophorine was isolated from a sample of Tylophora indica, and the crude extract was analyzed by HPLC/MS(n) and chiral HPLC/MS. While the literature states that the naturally occurring form of this alkaloid is the R-enantiomer and that its S-antipode is usually not found in nature, we confirmed the hypothesis of Govindachari and Nagarajan that natural levorotatory tylophorine is indeed a nearly racemic mixture with a slight excess of the R-enantiomer.

Food is the basic necessity of life. One works hard and earns to satisfy our hunger .But at the end of the day, many of us are not sure of what we eat. We may be eating a dangerous flavors and dyes. Often, we invite diseases rather than good health. The purpose of this article is to detect the presence of food adulterants in some common foods and to create awareness about the artificial tests and dyes. A study of the IR spectra and the optical activitiy of two natural and artificial most common used flavor and colors (Vanilla and Strawberry) were detected. IR spectra of synthetic Vanilla were dominated by specific peaks that attributed to corresponding synthetic pigments (specific spectral band of stretching C=0 ester of aldehydic and ketonic groups in synthetic flavor at1744.87cm -1 with a weak shoulder at1700 cm -1 . And stretching CO of sucrose at (990.49 and 923,70) cm -1 .The synthetic Strawberry characterized with specific spectral bands of (C=O stretching at 1634.96 cm -1 in ester and CO stretching of sucrose at 925 cm -1 ), while these functional groups disappeared in natural . Vanilla and Strawberry extracts. The natural Flavoring extracts posse's levorotatory property; they are optically active, while the synthetic extracts not rotates the plane of polarization of the light which passes through the material, they are said to be; not active optically. The obtained results indicated that, Infrared spectrum and Optical activity could be adapted to detect adulterants added products, and to differentiate between natural and artificial food flavoring extracts.

Sinoracutine is a recently isolated alkaloid with unusual stereochemical and biological properties. It features an unprecedented tetracyclic 6/6/5/5 skeleton that bears an N-methylpyrrolidine ring fused to a cyclopentenone. Interestingly, both enantiomers of sinoracutine have been independently isolated from the same plant, yet the molecule does not appear to occur as a racemate. Here, we present a short synthesis of (−)-sinoracutine that relies on a highly diastereoselective Pauson–Khand reaction and a Mandai–Claisen reaction to install the quaternary stereocenter. Our work establishes the absolute configuration of the levorotatory isomer and suggests that the optical purity of sinoracutine varies in nature due to its gradual racemization. Experimental evidence supports this proposal, and a plausible mechanism for the racemization is provided.

Micelle with mesomeric polyleucine (PDLLeu) core demonstrated the most uniform morphology, the smallest diameter and the highest drug loading capability compared to those with dextrorotatory (PDLeu), levorotatory (PLLeu) and racemic PLeu (PD/LLeu) cores. In addition, the modification with c(RGDfC) endowed the optimal PDLLeu micelle with enhanced intracellular drug release and cytotoxicity, indicating its great potential for targeted drug delivery.

В статье дана характеристика препарата L-цет — представителя ІІІ поколения антигистаминных препаратов, содержащего левовращающий изомер цетиризина. Приведены результаты лечения детей с атопическим дерматитом с использованием препарата L-цет, свидетельствующие о его высокой эффективности и безопасности.

International audience; Menthol, which is used in the food, pharmaceutical and cosmetics industries, was studied by flash scanning calorimetry. New levorotatory and racemic menthol polymorphs were thus identified. This study is also forward-looking regarding the use of organic molecules in flash scanning calorimetry, which is frequently used for polymer studies.

Preparation of the sulfite derived from racemic and (R)−(+)-enantiomer of BINOL is reported. The crystal structure of the optically active, levorotatory sulfite isomer and its ring opening induced by nucleophilic substitution reactions with selected nucleophiles are presented. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 22:562–570, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.20722

Neuraxial analgesia is frequently administered to women in labor. For many years, bupivacaine has been used because of its long duration of action, lack of excessive motor block, and minimal fetal and neonatal effects. However, bupivacaine is one of the most cardiotoxic local anesthetics in current use and motor block is still a problem. Many local anesthetics such as bupivacaine exist in 2 forms, levorotatory and dextrorotatory. Ropivacaine, an amide local anesthetic produced in the pure levorotatory form addresses some of the concerns related to bupivacaine. In this article, we present the literature comparing ropivacaine and bupivacaine to determine whether there is an advantage to using one of these local anesthetics for labor analgesia. We found that there is no advantage to the routine use of ropivacaine for labor analgesia.

In this study, we measured the urine concentrations of methamphetamine and amphetamine as metabolites of selegiline after ingestion of an overdose of selegiline. A patient who had developed Parkinson disease took selegiline in a suicide attempt. Analysis by gas chromatography-mass spectrometry (GC-MS) with trifluoroacetic acid-derivatization revealed the presence of methamphetamine and amphetamine in the patient's urine at concentrations of 0.62 microg/ml and 0.25 microg/ml, respectively. To determine the stereospecificity of the methamphetamine and amphetamine, a urine sample was analyzed by GC-MS after derivatization with N-(trifluoroacetyl)-l-prolyl chloride. The methamphetamine and amphetamine were levorotatory in form. The ratio of the methamphetamine to amphetamine concentration in the urine was 2.5. This value is consistent with other case reports of ingestion of selegiline, which suggests that the methamphetamine to amphetamine concentration ratio in urine is useful information for indicating use of selegiline.

The specific rotation of (S)-4-isopropyl-oxazolidin-2-one is extremely solvent dependent. In chloroform it is dextrorotatory { [ α ] D 26 = + 15.5 ( c 5.2 , CHCl 3 ) } , whereas in ethanol it is levorotatory { [ α ] D 26 = - 16.1 ( c 5.2 , EtOH ) } .

In conglomerates, each single crystal contains only one of the two possible enantiomeric forms—either dextrorotatory or levorotatory. The analysis of a single crystal by liquid chromatography on chiral support associated with chiroptical detection is a very efficient tool to reveal the occurrence of a conglomerate. In terms of rapidity and easiness, this method compares favorably with the classical methods used to show this occurrence. Two examples are provided. Chirality, 2007. © 2007 Wiley-Liss, Inc.

A phytochemical study of the EtOAc-soluble part of the methanolic extract of the bark of Endiandra kingiana led to the isolation of three new pentacyclic kingianins as racemic mixtures, kingianins O-Q (1-3), together with the known kingianins A, F, K, L, M and N (4-9), respectively. The structures of the new kingianins 1-3 were determined by 1D and 2D NMR analysis in combination with HRESIMS experiments. Kingianins A-Q were assayed for Mcl-1 binding affinity. Kingianins G and H were found to be potent inhibitors of Mcl-1/Bid interaction. A structure-activity relationship study showed that potency is very sensitive to the substitution pattern on the pentacyclic core. In addition, in contrast with the binding affinity for Bcl-xL, the levorotatory enantiomers of kingianins G, H and J exhibited similar binding affinities for Mcl-1 than their dextrorotatory counterparts, indicating that the two anti-apoptotic proteins have slightly different binding profiles.

Melasma is a common acquired and distressing pigmentary disorder presenting to dermatology clinics. It is notably difficult to cure and has a tendency to relapse. The efficacy of classical Q-switched laser in treatment of melasma remains controversial. This study aims to investigate the efficacy and safety of 694-nm fractional QSRL combined with sonophoresis on levorotatory vitamin C for the treatment of melasma patients. Twenty-six patients with melasma were enrolled. Each patient received four to six fractional QSRL treatments at pulse energies of 2.5 to 4 J/cm(2) combined with sonophoresis on levorotatory vitamin C at 2-week intervals. The severity and the area of melasma were assessed by two investigators using the melasma area and severity index (MASI). Side effects were documented. Mean MASI score decreased from 15.51 ± 3.00 before treatment to 10.02 ± 4.39 3 months after the final treatment (P

Optically active, or chiral, molecules make up the food we consume, parts of our homes and clothes, and every cell in our bodies. Every organism on our planet owes its existence to the way its molecules rotate plane-polarized monochromatic light. Depending on the particular optical molecule, it either rotates the polarized light to the right, dextrorotatory, or left, levorotatory. Such chiral molecules typically can be depicted as one of two mirror-images that are not superimposable (Fig. 1).

The naturally occurring γ-lactones (+)-methylenolactocin (13) and its enantiomer, (+)-protolichesterinic acid (14) and its enantiomer, (+)-rocellaric acid (15), and the methylene bis(γ-lactone) (–)-avenaciolide (16) were synthesized with 95–98 % ees in very few steps. Enantiocontrol was imposed by the asymmetric dihydroxylation of trans-configured β,γ-unsaturated carboxylic esters (namely compounds 1i, 1j, and 1n) with AD mix-α® [for the levorotatory target structures, except for (–)-avenaciolide] or AD mix-β® [for the dextrorotatory target structures plus (–)-avenaciolide]. β,γ-Unsaturated carboxylic ester 1e required increased amounts of the oxidant and auxiliary to produce the hydroxy lactone R,R-3e, a precursor of the naphtho-γ-lactone (+)-9-hydroxyeleutherol (12; 96 % ee). (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

New optically active levorotatory compounds [Ni(HL1)]NO3 (I) and [Ni(HL2)]NO3· H2O (II) containing the anions of chiral diaminodioximes, H2L1 and H2L2, derived from the terpenes ±-pinene and (+)-3- carene, respectively, were synthesized. Complexes I and II were studied by X-ray diffraction. The crystal structures of compounds are ionic, being composed of the [Ni(HL1)]+ or [Ni(HL2)]+ cations and the outer-sphere NO−3 anions. The Ni2+ ion coordinates four N atoms of the tetradentate chelating ligand, the NiN4 coordination unit being shaped like a tetrahedrally distorted square. Compounds I and II are diamagnetic, which corresponds to a low-spin d8 configuration. The NMR spectra of compounds were recorded and analyzed.

(R)-ar-Turmerone was synthesized from (4-methylphenyl)acetic acid by employing Evans asymmetric alkylation as the key step. (R)-ar-Turmerone was converted to (R)-ar-himachalene, which was dextrorotatory in hexane while levorotatory in chloroform. Enantiomerically impure (75% ee) (R)-3-(4-methylphenyl)butanoic acid crystallized more readily than the enantiomerically pure one.

A series of 1-phenyl-3-azabicyclo(3.1.0)hexanes were synthesized as more conformationally restricted prototypical σ ligands 3-phenylpiperidines with the aim to developing new σ ligands. Compared with 3-phenylpiperidines reported by Largent et al., binding data showed that conformational restriction was not detrimental for σ receptor affinity. Specifically, except for secondary amine 4, all racemic 1-phenyl-3-azabicyclo(3.1.0)hexane derivatives (12-19) showed moderate to high affinity for both σ1 and σ2 receptors. Dextrorotatory isomers with the same configuration of 3-phenylpiperidines to C-1 carbon linked to the phenyl ring showed a better affinity and selectivity for σ1 receptors compared to the respective levorotatory isomers. Compounds (+)-14 and (+)-15 displayed very high affinity for σ1 (Ki = 0.9 and 2.3 nM respectively) but low selectivity for receptor subtypes. Compound (+)-18 with N-phenethyl substituent embodies the highest selectivity for σ1 receptors.

Acylation of meso-2,3-dimethylbutane-1,4-diol with vinyl acetate in the presence of porcine pancreatic lipase (PPL) leads to the dextrorotatory monoacetate of the above diol with enatiomeric excess (ee) 58—64%. Absolute configuration of this scalemic specimen was determined by its sequential transformation to levorotatory lasiol, a metabolite of the Lasius ants. Partial hydrolysis of the corresponding meso-diacetate, mediated by PPL or by the Pseudomonas sp. lipase affords the monoacetate of opposite configuration with ee 72—86%, a formal intermediate in the synthesis of (3S,4R)-faranal. Other microbial lipases used are distinctive in low chemoselectivity.

Heartwood ofChamaecyparis obtusa contains significant amounts of a dibenzylbutyrolactone lignan, hinokinin (8). This investigation demonstrated that the contents of 8 and a norlignan, hinokiresinol (12), were higher in the heartwood region than in the sapwood, indicating their nature of being heartwood extractives. Eleven lignans — xanthoxylol (1), 7-oxohinokinin (2), savinin (3), dihydrosesamin (4), isoactifolin (5), sesamin (6), piperitol (7), hinokinin (8), pluviatolide (9), haplomyrfolin (10), and rnatairesinol (11) — were isolated from young shoots ofChamaecyparis obtusa cv. Breviramea. Eight lignans (1, 2, 4, 5, 7, 9,10, and11) were isolated from this plant for the first time. Chiral high-performance liquid Chromatographie analysis showed that8, 9, 10, and11, were found to be levorotatory and optically pure (>99% e.e.). Based on the chemical structures of the isolated lignans, possible biosynthetic pathways of8 are discussed.

Vibrational absorption and circular dichroism spectra of dextrorotatory, levorotatory, and racemic mixture of tert-butylphenylphosphinothioic acid have been measured in CCl(4) solutions in the 2000-900 cm(-1) region. The conformations for both tautomeric structures of (S)-tert-butylphenylphosphinothioic acid are investigated using the B3LYP functional with the 6-31G* basis set. For the most stable conformation, the absorption and VCD spectra are predicted ab initio using the B3LYP functional with 6-31G*, 6-311G(2d, 2p), 6-31+G, and 6-311G(3df, 3pd) basis sets. A different functional, B3PW91, was also used with the 6-31G* basis set. The predicted spectra are compared to the experimental spectra. The comparison indicates that (-)-tert-butylphenylphosphinothioic acid is of the (S)-configuration and exists in only one tautomeric structure and one conformation in CCl(4) solution.

High grade single crystals of (GaxIn1−x)2Se3 showing giant optical activity for visible and infrared light have been successfully grown with an iodine transport technique. Two kinds of single crystals with reverse rotatory directions to each other have been obtained; one is the dextrorotatory with space group P61 and another is the levorotatory with P65. The composition x is controlled from 0.03 to 0.70. The morphology is hexagonal plate and the size is up to 3 mm in diameter and hundreds of microns in thickness. The crystals for different compositions x possess different fundamental optical absorption edges from 610 to 720 nm. The crystal habit facets are the (001) and {110} planes. These crystals have a polarity and their growth direction is limited to the [00-1] direction. The lattice defects such as antiphase domain boundary, stacking fault, inversion twin, and reversion screw almost have not been observed. It is found that these growth characteristics are strongly related to the crystal structure in which the structural vacancies are ordered in screw form along the c axis.

In a rebreathing anesthesia circuit, the inhaled anesthetic sevoflurane degrades into at least two products, termed "compound A" and "compound B." The enantiomer separation of the chiral compound B (1,1,1,3,3-pentafluoro-2-(fluoromethoxy)-3-methoxypropane ) by capillary gas chromatography (cGC) using heptakis (2,3-di-O-acetyl-6-O-tert-butyldimethylsilyl)-beta-cyclodextrin as chiral selector was studied. With this cyclodextrin derivative diluted in the polysiloxane PS 86, an unprecedented high separation factor alpha of 4.1 (at 30 degrees C) was found. Consequently, the enantiomers of compound B were isolated by preparative GC and their specific rotations were measured. In addition, their absolute configurations were determined by X-ray crystallography. To collect the X-ray data, single crystals of both enantiomers were grown in situ on the diffractometer. The levorotatory enantiomer B(-) has the R-configuration while the dextrorotatory enantiomer B(+) has the S-configuration. The elution order of the compound B enantiomers on heptakis (2,3-di-O-acetyl-6-O-tert-butyldimethylsilyl)-beta-cyclodextrin is R before S.

A stereoselective total synthesis of natural levorotatory polycavernoside A (1) has been achieved. Initial investigations produced the properly activated disaccharide unit 18b via the conjoining of building blocks originating from l-fucose and d-xylose. This objective was followed by preparation of the phenylsulfonyl-substituted tetrahydropyran 23 and aldehyde 30. After proper linking of these key compounds, important information had to be garnered on the sequence of steps that would ultimately result in successful access to 1. Although oxidation to generate α-diketone 35 and unmasking of the C-13 hydroxyl did give rise efficiently to lactol 36, this functionality did not pave the way for ensuring macrolactonization. When this sequence of steps was reversed, it was indeed possible to arrive at the heavily functionalized precursor 44. However, numerous experiments failed to result in the requisite activation of C-16 for attachment of the trienyl side chain. However, if the E-vinyl iodide was elaborated in ...

Resolution of insect pheromonal cis-epoxydiene racemates derived from (Z,Z,Z)-3,6,9-trienes was examined with a reversed-phase chiral HPLC column. The results showed that a Chiralcel OJ-R column was suitable for separating the enantiomers having a C17–C23 unsaturated straight chain except for 9,10-epoxydienes with a C21–C23 chain. To determine the absolute configuration of the separated enantiomers, each of the optically active epoxydienes was hydrogenated over Pd-BaSO4 and its behavior was examined on this chiral column by cochromatography with the corresponding chiral epoxy compound having a saturated chain, which was prepared via a Sharpless epoxidation reaction. This analysis showed that the dextrorotatory C17–C23 3,4- and 6,7-epoxydienes and C17–C20 9,10-epoxydienes with shorter Rts possess (3S,4R)-, (6S,7R)-, and (9R,10S) configurations, respectively, and the levorotatory enantiomers with longer Rts possess the opposite configuration. An abdominal tip extract of the mulberry looper, Hemerophila artilineata Butler (Lepidoptera: Geometridae: Ennominae), included (9S,10R)-(Z,Z)-cis-9,10-epoxy-3,6-octadecadiene as a main sex pheromone component. The synthetic (9S,10R)-9,10-epoxydiene, rather than its antipode, elicited strong antennal and behavioral responses from the male moths in electrophysiological and field tests.

The levorotatory enantiomer of t-butylsulfinylacetic acid 3 was obtained in the reaction of the α-carbanion of (+)-t-butyl methyl sulfoxide 1 with carbon dioxide. The same enantiopure form of the acid 3 was isolated from its diastereomerically pure levorotatory salt 5 with (−)-(1R,2S)-ephedrine. The structure of this salt was determined by X-ray analysis and the absolute configuration (S) at sulfur was ascribed to the t-butylsulfinylacetate anion. Consequently, the absolute configuration (S) was assigned to the acid (−)-3 and its precursor (+)-t-butyl methyl sulfoxide 1.

A total synthesis of natural levorotatory spinosyn A (1) has been achieved. The first objective, to confirm the absolute configurational assignment of tricyclic ketone 2 prepared earlier, was accomplished by oxidative degradation of the macrocyclic lactone ring in 1. The route began with the implementation of a four-step one-pot process that resulted in the efficient conversion of 6 into 18. A combination of periodate cleavage and peracid oxidation events then led to 2. In the reconstruction phase, a Pd-catalyzed coupling of a vinylstannane with an acid chloride reestablished the great majority of the structure in an enantiocontrolled manner. Once macrolactonization had been effected, the 2,3,4-tri-O-methylrhamnose unit was introduced first with exceptionally good stereocontrol. The final glycosidation, which involved a 2-mercaptopyrimidine derivative of d-forosamine, was met with an expectedly diminished percentage of the desired β-anomer.

Novel optically active aromatic isocyanates, 3-((S)-(α-methylbenzyl)carbamoyl)phenyl isocyanate ((S)-3MBCPI) ([α]36525 +63°) and 4-((S)-(α-methylbenzyl)carbamoyl)phenyl isocyanate ((S)-4MBCPI) ([α]36525 +181°), were synthesized and homopolymerized or copolymerized with m-methoxyphenyl isocyanate (mMeOPI) with an anionic initiator in THF at −98 °C. Poly((S)-3MBCPI) showed a very large levorotatory specific rotation ([α]36525 −1969°) and an intense CD absorption due to a predominantly one-handed helical conformation of the polymer main chain. Copolymers of (S)-3MBCPI with mMeOPI showed much larger specific rotation than that expected from the (S)-3MBCPI content. The intensity of the specific rotation of the copolymer of [mMeOPI]/[(S)-3MBCPI] = 91/9 greatly increased with a decrease in temperature, but that of poly((S)-3MBCPI) showed almost no change, suggesting that poly((S)-3MBCPI) may take a perfectly single-handed helical conformation in solution even at room temperature. Poly((S)-4MBCPI) showed a large ...

(−)-(R)-4,4,4,4′,4′,4′-Hexafluorovaline hydrochloride ((R)-5) of 98% ee is prepared from β,β-bis(trifluoromethyl)acrylic acid (= benzyl 4,4,4-trifluoro-3-(trifluoromethyl)but-2-enoate; 1) in 4 steps with an overall yield of 9.6%. Key step is the separation of the TsOH salts of the diastereoisomers obtained by anti-Michael addition of (+)-(R)-1-phenylethylamine (2) to 1 ( (R,R)-3). In contrast to the published (S)-chirality, the X-ray structure analysis of (R,S)-6 reveals, that (R)-chirality has to be assigned to the levorotatory (−)-4,4,4,4′,4′,4′-hexafluorovaline hydrochloride.