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A few new α- and β- d -galactopyranoside-based chiral lariat ethers of monoaza-15-crown-5 type were synthesized. These macrocycles proved to be efficient catalysts in a few asymmetric reactions under mild phase transfer conditions. The catalytic effect of the lariat ethers with methoxy, ethoxy, isopropoxy and aryloxy substituents on the C-1 of the sugar unit in both α and β positions was compared. In the presence of β- d -galactopyranoside-based crown ethers, the asymmetric Darzens condensation of α-chloroacetophenone and benzaldehyde, the epoxidation of trans -chalcone, the cyclopropanation (MIRC reaction) of benzylidenemalononitrile and 2-benzylidene-1,3-indandione with diethyl bromomalonate were performed with enantioselectivities of 61%, 64%, 86% and 96%, respectively. In all reactions, the β-anomers were more efficient in terms of enantioselectivity than the α forms. Image 1 [ABSTRACT FROM AUTHOR]

Optically active cyclopropane derivatives were prepared by a novel, simple and green approach in high enantioselectivities using monosaccharide-based chiral crown ethers as phase transfer catalysts. The crown ethers having d -glucopyranoside, d -mannopyranoside and d -altropyranoside units proved to be efficient catalyst in a few asymmetric phase transfer cyclopropanation reactions. The Michael-initiated ring closure (MIRC) reactions of diethyl bromomalonate with chalcones took place with complete diastereoselectivity and up to 99% ee. Using benzylidenemalononitrile, 2-arylidenemalononitriles, 2-benzylidene-1,3-indandione, substituted 2-benzylidene-1,3-indandiones, 2-arylidene-1,3-indandiones and 2-benzylidene-1,3-diphenyl-1,3-propanediones enantioselectivities up to 92%, 99%, 54% 93%, 89% and 72%, respectively, were achieved, in the presence of chiral lariat ethers derived from different monosaccharides. The absolute configuration of a cyclopropane diester product was determined by a combined CD spectroscopic and theoretical study. [ABSTRACT FROM AUTHOR]

A monoaza-15-crown-5 lariat ether derived from d -glucose 1 has been applied as a chiral phase-transfer catalyst in the Michael addition of diethyl, dimethyl, diisopropyl and dibenzyl malonates to enones under mild conditions to afford the adducts with good to excellent enantioselectivities. In the reaction of diethyl malonate with substituted trans -chalcone, the adducts with in enantioselectivities up to 89% ee. Among the reactions of substituted diethyl malonates, those of diethyl acetoxymalonate gave the best results (96% ee). The effect of the substituents of the chalcone was also investigated in reactions with diethyl acetoxymalonate. Among the chalcones substituted on the β-aryl, the para -substituted compounds resulted in the highest enantioselectivities (88–97% ee). The substituents on the benzoyl aryl of chalcone caused a decrease in the enantioselectivity compared to the unsubstituted case. The adducts with furyl or thiophenyl substituents were formed with >99% ee. The glucose-based catalyst also proved to be effective in the cases of diisopropyl and dibenzyl acetoxymalonates (including ees up to 99% ee). The reactions of diethyl acetoxymalonate with cyclic enones gave the corresponding Michael adducts with enantioselectivities up to 83%. The absolute configuration of one of the new Michael adducts was determined by CD spectroscopy. [ABSTRACT FROM AUTHOR]

This paper reports the preparation of newly synthesized sugar-based epoxy monomers, suitable for replacing petrochemical-derived epoxy resins of high thermal stability. Several bi- tri- and tetrafunctional epoxy components were prepared from d -glucose, among them the glucopyranoside- and glucofuranoside-based trifunctional ones proved to be the most promising for high-tech applications. The applicability of the synthesized compounds as epoxy monomers was investigated by curing probes with a model aromatic amine-type hardener. The curing enthalpy of the bioepoxy resins were examined, and compared to theoretical values, as well as the glass transition temperature, which is a crucial parameter when determining the potential fields of application of the bioresins. T g values up to 175 °C were reached, while the thermal degradation of the cured resins start at around 300 °C. [ABSTRACT FROM AUTHOR]

Abstract: The asymmetric Michael addition of diethyl malonate and α-substituted diethyl malonates to aromatic nitroalkenes was carried out under mild reaction conditions in a solid–liquid phase transfer reaction in the presence of α-d-glucopyranoside- and α-d-mannopyranoside-based crown ethers as the catalysts. The use of d-glucose-based lariat ether 1 gave the best results. The substituents of the β-nitrostyrene and the diethyl malonate had a significant impact on the chemical yields and enantioselectivity. The addition of diethyl-2-acetamidomalonate to aromatic nitroalkenes afforded the corresponding Michael adducts in moderate to high enantiomeric excess (ee up to 99%). The reaction of diethyl-2-methylmalonate with 2-nitro-β-nitrostyrene gave the adduct with 93% enantiomeric excess in the presence of crown catalyst 1. [Copyright &y& Elsevier]

Abstract: The synthesis of four new ribo-hexopyranoside-based chiral lariat ethers of monoaza-15-crown-5 type and two altropyranoside-based crown ethers were elaborated. Our syntheses utilized the regioselective ring opening of the oxiran moiety of the 2,3-anhydro sugars by nucleophilic reagents to afford the key intermediates. The reaction of methyl-2,3-anhydro-4,6-O-benzylidene-α-d-mannopyranoside with ethanolamine is especially of interest to afford a 3-substituted altropyranoside. One of the ribo-hexopyranoside-based lariat ethers with a 4-methoxyphenyl substituent induced an enantioselectivity of 80% when used as catalyst in the Michael addition of diethyl acetamidomalonate to trans-β-nitrostyrene under phase transfer catalytic conditions. [Copyright &y& Elsevier]

Abstract: Liquid–liquid phase asymmetric Darzens condensations were carried out in the presence of d-glucose- and d-mannose-based crown ethers 1 and 2 as the catalyst. The use of d-glucose-based lariat ether 1 as the catalyst gave the best results. The reaction of 4-phenyl-α-chloroacetophenone, 2-chloro-1-tetralone, and 2-chloro-1-indanone with various aromatic aldehydes afforded the corresponding aromatic α,β-epoxyketones in moderate to high enantiomeric excess (ee up to 96%) under mild reaction conditions. The substituents of the benzaldehyde used as the reactants had a significant impact on the chemical yields and enantiomeric excess. The absolute configuration of some epoxyketone products was determined by single-crystal X-ray analysis. [Copyright &y& Elsevier]

Abstract: Heteroaromatic epoxyketones have been synthesized in an asymmetric Darzens condensation of 2-chloroacetylfuran or 2- and 3-chloroacetylthiophene with aromatic aldehydes and in the enantioselective epoxidation of α,β-enones with an N-methylpyrrole unit, in both cases in the presence of d-glucose- 1 or d-mannose-based 2 crown ethers as phase transfer catalysts. The use of d-glucose-based 1 lariat ether as the catalyst gave the best results. The α,β-epoxyketones with a furan or a thiophene moiety were obtained in good enantioselectivities (up to 86% ee) as well as excellent diastereoselectivities (up to 98:2), but the epoxyketones with a pyrrole-ring were formed in the Darzens condensation in low yields and enantioselectivities. The epoxyketones with an N-methylpyrrole moiety isolated from the epoxidation of the corresponding α,β-enones were obtained in significant enantioselectivities (in ee values up to 81%) in the presence of catalyst 1 under mild reaction conditions. [Copyright &y& Elsevier]

Abstract: Liquid–liquid phase asymmetric Darzens condensations were promoted by d-glucose- and d-mannose-based crown ethers. The corresponding aromatic and heteroaromatic α,β-epoxyketones were obtained with moderate to high enantioselectivities (up to 96%) as well as diastereoselectivities (up to 98:2) under mild reaction conditions. The absolute configurations of several of the epoxyketones were determined by single crystal X-ray analysis. The Michael additions of diethyl acetylaminomalonate to trans-β-nitroalkenes were carried out in a solid–liquid two-phase system in the presence of a d-glucose-based crown catalyst with up to 99% ee. [Copyright &y& Elsevier]

Abstract: The chiral monoaza-15-crown-5 lariat ethers annellated to methyl-4,6-O-benzylidene-α-d-glucopyranoside-1 or mannopyranoside 2 have been applied as phase-transfer catalysts in the epoxidation of substituted chalcones and chalcone analogues with tert-butylhydroperoxide resulting in significant asymmetric induction. It was found that the position of the substituents in the aromatic ring of the chalcone had an influence both on the chemical yields and enantiomeric excesses. The lowest enantioselectivities (62–83% ee) were found in the case of ortho-substituted model compounds. The highest ee values (ee of 83–97%) were obtained in the case of para-substituted models. From among the chalcone analogues, the maximum ee (90–92%) was detected for the model compound having α-tert-butyl- and β-aryl groups. Using glucose-based crown ether 1, formation of the (−)-enantiomer was preferred, while applying mannose-based 2 as the catalyst, the (+)-enantiomer was in excess. [Copyright &y& Elsevier]

A few new d -galactose- and d -glucose-based monoaza-15-crown-5 type lariat ethers have been synthesized. These macrocycles and their derivatives proved to be efficient catalysts in the cyclopropanation of (E)-3-phenyl-2-(phenylsulfonyl)acrylonitrile performed with diethyl bromomalonate under mild phase transfer conditions. Among the catalysts tested, the macrocycle having methyl α- d -galactopyranoside unit generated the highest asymmetric induction (80% ee). In the reactions of the aryl-substituted phenylsulfonyl-acrylonitrile derivatives, the cyclopropanation of the meta - and para- substituted starting materials took place with high ee values (75–84% ee). The cyclopropane derivatives synthesized from analogous α,β-unsaturated cyanosulfones containing naphthyl, pyridyl, furyl and thienyl groups were obtained with enantioselectivities up to 85%, and in excellent yields. Image 1 • New d -glucose- and d -galactose-based crown ethers have been synthesized. • A new catalyst induced enantioselectivity up to 85% in the MIRC reaction of α,β-unsaturated cyanosulfones. • The m - and p -substituted products were formed with 75–84% ee, while the o -substituted cyclopropanes with 0–12% ee. • The new chiral cyclopropanes may be important intermediates in asymmetric syntheses. [ABSTRACT FROM AUTHOR]

The objectives of this work were to develop meloxicam based amorphous solid dispersion through electrospinning technique and evaluate the effect of the polymeric matrix on the physicochemical properties of the fibers and the downstream processing ability to orodispersible dosage forms. Drug – polymer interactions formed between Eudragit E and meloxicam, confirmed through Raman and 1HNMR spectra, enabled the development of fibers from ethanol, thus allowing an increased production rate compared to PVPk30 where a DMF:THF solvent system was suitable. Microflux dissolution-permeation studies showed a significantly higher diffusion from amorphous solid dispersions compared to crystalline meloxicam. The flux through the membrane was influenced by the polymers only under basic conditions, where the precipitation of Eudragit E limited the complete resolubilization of the active ingredient. This phenomenon was not observed during large volume conventional dissolution testing. The effect of formulation on long term stability could not be highlighted as all products were stable up to 15 months, stored in closed holders at 25 °C ± 2 °C and 50%RH ± 10%. The increased surface area of fibers enabled tablet preparation with low pressures due to favorable bonding between particles during compression. PVPk30 formulation presented higher tabletability and compactability, as higher tensile strength compacts could be prepared. Eudragit E formulation had lower detachment and ejection stress, suggesting a lower sticking tendency during tableting. The presence of HPßCD in PVPk30 formulation offered improved morphological features of the fibers, however no significant effect was observed on dissolution, permeation or mechanical properties. Downstream processing was guided by polymer mechanical properties and solubility, thus PVPk30 fibers could be delivered in the form of orodispersible webs and conventional tablets, whereas Eudragit E fibers as orodispersible tablets. [ABSTRACT FROM AUTHOR]

The aim of this work was to develop a PAT platform consisting of four complementary instruments for the characterization of electrospun amorphous solid dispersions with meloxicam. The investigated methods, namely NIR spectroscopy, Raman spectroscopy, Colorimetry and Image analysis were tested and compared considering the ability to quantify the active pharmaceutical ingredient and to detect production errors reflected in inhomogeneous deposition of fibers. Based on individual performance the calculated RMSEP values ranged between 0.654% and 2.292%. Mid-level data fusion consisting of data compression through latent variables and application of ANN for regression purposes proved efficient, yielding an RMSEP value of 0.153%. Under these conditions the model could be validated accordingly on the full calibration range. The complementarity of the PAT tools, demonstrated from the perspective of captured variability and outlier detection ability, contributed to model performance enhancement through data fusion. To the best of the author's knowledge, this is the first application of data fusion in the field of PAT for efficient handling of big-analytical-data provided by high-throughput instruments. [ABSTRACT FROM AUTHOR]