Hydrolysis of new phthalimide-derived esters catalyzed by immobilized lipase

The last step of the production of four phthalimide-derived acids, designed to act as antiasthma drugs, was performed by enzymatic hydrolysis of the respective methyl or ethyl esters. The esters 4-ethyl-[2-(1,3-dioxo-1,3-dihydro-2-isoindoylyl)]-phenoxyacetic methyl ester (PHT-MET), 4-ethyl-[2-(1,3-dioxo-1,3-dihydro-2-isoindoylyl)]-phenoxyacetic ethyl ester, 4-(1,3-dioxo-1,3-dihydro-2-isoindoylyl)-phenoxyacetic ethyl ester, and 2-(1,3-dioxo-1, 3-dihydro-2-isoindoylyl)-phenoxyacetic ethyl ester were hydrolyzed by immobilized lipase. The enzymatic reaction could be used only to produce the desired 4-substituted compounds. The best result that was found to hydrolysis of PHT-MET, and, therefore, that ester was selected for optimization experiments in a three-phase system. Reactions were performed with solid biocatalyst (Lipozyme® RM IM), organic solvent phase (ethyl acetate), and aqueous phase (saturated Na₂CO₃ solution). To optimize the reaction conditions, an experimental design optimization procedure was used. The variables studied were the amount of enzyme, the temperature, and the volume of the aqueous solution. Time course experiments were then performed for different initial enzyme concentrations (0.5, 0.9, and 1.4 U_H/mL of solvent). The optimized reaction conditions found were 20 mg of Lipozyme (0.9 U_H/mL_solvent) and 5.0 mL of Na₂CO_3(sat) at 40°C for 6 h.     

NMR Conformational Analysis and Theoretical Calculations for 2‐Aryl‐ 1,3‐dihydroxy‐4,4,5,5‐tetramethylimidazolidines

Conformational studies of 1,3‐dihydroxy‐4,4,5,5‐tetramethyl‐2‐(pyridin‐1‐yl)imidazolidine ( 1a ) and 1,3‐dihydroxy‐4,4,5,5‐tetramethyl‐2‐(pyridin‐3‐yl)imidazolidine ( 1b ), carried out by using 1D ¹H‐ and ¹³C‐NMR and 2D HMQC, HMBC, and NOESY experiments and with the aid of theoretical calculations, indicate that the OH groups are trans to the pyridinyl substituent. Because the two ¹H‐NMR signals of the Me groups are distinguishable and do not change between 290 and 380 K, it is proposed that 1a and 1b have each only one conformation in this temperature range. This behavior was not found with 1,3‐dihydroxy‐4,4,5,5‐tetramethyl‐2‐(pyridin‐2‐yl)imidazolidine ( 1c ) because its Me ¹H‐NMR signals cross over at 300 K. Hence, more than one conformation must be present, beyond those produced by simple inversions. Theoretical calculations including temperature and solvent effects were performed to provide further information on the conformational analysis and to help to assign the NMR data. The combination of NMR measurements and quantum‐chemical calculations is shown to be a very promising strategy for conformational analysis studies in solution.     

Ruthenium(III)- and osmium(VIII)-catalyzed oxidation of 2-thiouracil by bromamine-B in acid and alkaline media: a kinetic and mechanistic study

The kinetics of oxidation of 2-thiouracil (TU) by sodium N-bromobenzenesulphonamide or bromamine-B (BAB) have been studied in an HCl medium, catalyzed by RuCl₃, and in a NaOH media with OsO₄ as catalyst, at 313 K. The stoichiometry and oxidation products are the same in both cases, but their kinetic patterns were found to be different. In acid medium the rate shows a first order dependence in each of [BAB] and [TU], and is dependent on [Ru^III]. The reaction rate is inversely dependent on [H⁺]. In alkaline medium, the rate is first order in [BAB] and in [Os^VIII] and zero order in [TU]. The reaction rate is dependent on [NaOH]. Activation parameters have been evaluated, solvent isotope effects have been studied in D₂O medium, and equilibrium constants were calculated. The activation parameters and rate constants indicate that the catalytic efficiency is: Os^VIII > Ru^III. The proposed mechanisms and the derived rate laws are consistent with the observed kinetics.     

Crystal and molecular structure and magnetic exchange properties of bis(di-micro-ethoxo-bis(3,5-di-tert-butylsemiquinonato)dicopper(II)) complex. A synergy between DFT and experimental magnetochemistry

The compound bis(di-micro-ethoxo-bis(3,5-di-tert-butylsemiquinonato)dicopper(II)) has been synthesized and its structure was determined by single-crystal X-ray diffraction. The compound crystallizes in the monoclinic system, space group C2/c, with a = 37.736(8) A, b = 9.173(2) A, c = 23.270(5) A, beta = 122.24(3) degrees. The structure can be described as a Lewis adduct between two dinuclear [Cu(DBSQ)(C(2)H(5)O)](2) units (DBSQ = 3,5-di-tert-butyl-semiquinonato). The temperature dependence of the magnetic susceptibility was efficiently analyzed by a combined DFT/experimental approach, showing that a rather strong ferromagnetic interaction exists between the DBSQ(-) and the copper(II) ions modulated by an antiferromagnetic interaction between the two copper(II) ions of the dinuclear units. Weak antiferromagnetism between the two units in the unit cell was measured.     

A polypyrrole/polymethylene pattern on gold using a micro-contact printing technique

A micro-contact printing technique was used to fabricate a polypyrrole/polymethylene pattern on a gold surface. ω-(N-Pyrroyl)undecanethiol (PyC₁₁SH) acts as ink for the generation of a pyrrole-terminal monolayer patterned on gold. This monolayer-patterned surface functions as a resist for the selective growth of polymethylene by catalytic decomposition of diazomethane on the gold surface. It also functions as a monomer for the electrochemical polymerization of pyrrole on the PyC₁₁SH monolayer-patterned surface. The polypyrrole/polymethylene pattern was fabricated by an electrochemical polymerization method. The polypyrrole was grown on the pyrrole-patterned surface by potential scanning between 0.0 and 1.2 V vs. Ag wire. The thickness of the polypyrrole growth increases with the increasing number of cycles. The structural features of the patterned surface can be determined by scanning electron microscopy and atomic force microscopy. Electronic Publication     

Biosynthesis and antioxidant activity of 4NRC β-glycoside

This Letter describes glycosylation of 4-Nerolidylcatechol (4-NRC) the major secondary metabolite from Pothomorphe peltata and Pothomorphe umbellata showing remarkable antioxidant, antimalarial, anti-inflammatory, and anti-HIV activities. One step biosynthesis was catalyzed by Cunninghamella echinulata ATCC 9245 and the reaction was undertaken in PDSM medium at 27 °C, 200 rpm for 96 h. After purification by silica gel flash column chromatography the 4-NRC β-glycoside was identified by ultrahigh resolution mass spectrometry and ¹H NMR. The antioxidant activity was evaluated by differential pulse voltammetry.     

Design,synthesis, characterization,and biological evaluation of pyrido[1,2-a]pyrimidinone coumarins as promising anti-inflammatory agents

Pursuing our recent interest regarding antimicrobial and anti-inflammatory activities of coumarin derivatives, we have synthesized a series of coumarin-linked pyridopyrimidinones by using Baylis Hillman adduct in aqueous condition with high purity. Pyrido[1,2-a]pyrimidin-2-ones are important class of heterocyclic compounds because of their use in medicinal and agro chemistry as active agents. All these newly synthesized compounds were evaluated for their antimicrobial and anti-inflammatory activity. Coumarin pyridopyrimidinones showed excellent anti-inflammatory activity against both MMP-2 and MMP-9 gelatinase zymography, whereas considerable good activity against Gram-positive and Gram-negative bacterial strains; however, antifungal activity observed in these series is more or less inactive. The active compounds of these series would be promising structural templates for the development of novel and more efficient anti-inflammatory agent.     

Performance comparison of retailing stores using a Malmquist-type index

This study develops a framework that combines different management science methods to provide insights concerning the performance of retailing stores. First, the framework enables to specify appropriate targets for stores of a retail network using data envelopment analysis. This involves comparing stores within homogenous groups, that is, supermarkets and hypermarkets. Second, the framework compares the overall performance of these two groups. This requires the combined use of a Malmquist-type index and statistical tests. This index is decomposed into sub-indices for comparing the differences between groups in terms of the efficiency spread in each group of stores and the productivity differences between the best-practice frontiers spanned by the benchmark stores from each group. The hypothesis tests are used to verify if the differences between groups captured by the sub-indices are statistically significant.     

A green-emitting α-substituted β-diketonate Tb3+ phosphor for ultraviolet LED-based solid-state lighting

The α-substituted β-diketonate [Ln(3Cl-acac)₃(H₂O)₂] [Ln = Tb, Gd] complexes (with 3Cl-acac^– being 3-chloro-2,4-pentanedionate) were characterized by elemental analysis, infrared, ultraviolet (UV)-visible and photoluminescence spectroscopies. For comparison purposes regarding photoluminescence, the well-known [Tb(acac)₃(H₂O)₂] complex was also synthesized. By considering the phosphorescence spectra of [Gd(3Cl-acac)₃(H₂O)₂], the effect of chloride replacement of hydrogen on the triplet state energy of the 3Cl-acac ligand was revealed. To support the interpretation and rationalization of the experimental results, Time-dependent DFT calculations were performed on Tb(3Cl-acac)₃(H₂O)₂. Additionally, the possibility of Tb(3Cl-acac)₃(H₂O)₂ to be used as potential green-emitting phosphor material for solid-sate light emitting diodes was evaluated. A prototype was successfully fabricated coating a near-UV LED (370 nm) with the Tb(3Cl-acac)₃(H₂O)₂ complex.     

Sweet Cherries as Anti-Cancer Agents: From Bioactive Compounds to Function

Sweet cherries (Prunus avium L.) are among the most appreciated fruits worldwide because of their organoleptic properties and nutritional value. The accurate phytochemical composition and nutritional value of sweet cherries depends on the climatic region, cultivar, and bioaccessibility and bioavailability of specific compounds. Nevertheless, sweet cherry extracts are highly enriched in several phenolic compounds with relevant bioactivity. Over the years, technological advances in chemical analysis and fields as varied as proteomics, genomics and bioinformatics, have allowed the detailed characterization of the sweet cherry bioactive phytonutrients and their biological function. In this context, the effect of sweet cherries on suppressing important events in the carcinogenic process, such as oxidative stress and inflammation, was widely documented. Interestingly, results from our research group and others have widened the action of sweet cherries to many hallmarks of cancer, namely metabolic reprogramming. The present review discusses the anticarcinogenic potential of sweet cherries by addressing their phytochemical composition, the bioaccessibility and bioavailability of specific bioactive compounds, and the existing knowledge concerning the effects against oxidative stress, chronic inflammation, deregulated cell proliferation and apoptosis, invasion and metastization, and metabolic alterations. Globally, this review highlights the prospective use of sweet cherries as a dietary supplement or in cancer treatment.