New Pregnane Glycosides from Mandevilla dardanoi and Their Anti-Inflammatory Activity

Mandevilla Lindl. is an important genus of the Apocynaceae family, not only as ornamental plants but also for its medicinal uses. In Brazil, Mandevilla species are indicated to treat asthma and skin infections, their anti-inflammatory potential and wound healing properties are also reported in the literature. Concerning their chemical composition, this group of plants is a conspicuous producer of pregnane glycosides. Mandevilla dardanoi is an endemic species from the Brazilian semiarid region not studied by any phytochemical methods. In view of the medicinal potential of Mandevilla species, this study aimed to isolate new pregnane glycosides from M. dardanoi. To achieve this main goal, modern chromatography techniques were employed. Five new pregnane glycosides, dardanols A-E, were isolated from the roots of M. dardanoi by HPLC. Their structures were determined using extensive 1D and 2D-NMR and mass spectrometry (MSⁿ and HRESIMS) data. The cytotoxicity and the anti-inflammatory potential of these compounds were evaluated. The first was evaluated by measuring proinflammatory cytokines and nitric oxide production by stimulated macrophages. Dardanols were able to inhibit the production of nitric oxide and reduce IL-1β and TNF-α. The current work demonstrates the chemodiversity of Brazilian semiarid species and contributes to amplifying knowledge about the biological potential of the Mandevilla genus.     

Diels-Alder reactivity of 4-aryl-1-phthalimido-2-siloxy-1,3-butadienes

The reaction of (1Z,3E) and (1E,3E) 4-aryl-1-phthalimido-2-trialkylsiloxy-1,3-butadienes with maleimides and quinones has been studied. The observed exo-stereospecifity can be attributed to the simultaneous presence of the phthalimido and aryl groups, which produce strong hindrance during the endo approach.     

A fuzzy finite element procedure for the calculation of uncertain frequency response functions of damped structures: Part 2—Numerical case studies

This work introduces a numerical algorithm to calculate frequency response functions of damped finite element models with fuzzy uncertain parameters. Part 1 of this paper focusses on the numerical procedure for the solution of the underlying interval finite element problem, based on the undamped procedure and the principle of Rayleigh damping. Part 2 of this paper illustrates the applicability of the methodology through four case studies. The concepts of the interval and the fuzzy finite element frequency response function analysis are illustrated for different types of uncertainties. The obtained results are compared with the results of Monte Carlo simulations.     

Multiple Zeolite Structures from One Ionic Liquid Template

This study reports the use of 1‐butyl‐3‐methyl imidazolium methanesulfonate ionic liquid as a template in the synthesis of zeolites. It is found that the silicon source determines the formation of beta (BEA), mordenite framework inverted (MFI), or analcime (ANA) zeolites. Depending on this source, different preorganized complexes are obtained that drive the formation of the different zeolite structures. In the presence of ethanol, the ionic liquid form preorganized complexes that drive the formation of MFI. In its absence, BEA is obtained. Whereas, the large amount of sodium present when using sodium metasilicate leads to ANA formation. A molecular simulation study of the relative stability of the template‐framework system and location of the template provides further insight into the mechanism of synthesis.     

On the Parametric Decomposition Theorem in Multiobjective Optimization

An example is given to show the inadequacy of a well-known result, concerning the parametric decomposition theorem for multiobjective optimization problems. We also give an accurate decomposition theorem, which generalizes a corrected reformulation of this result.     

Linear polyurethanes derived from alditols and diisocyanates

A set of linear [m,n]‐type polyurethanes was synthesized by polycondensation in solution from hexamethylene diisocyanate and 4,4′‐methylene‐bis(phenyl isocyanate) with alditols. Threitol, arabinitol, and xylitol bearing the secondary hydroxy groups blocked as methyl ethers were used. Either regioregular or nonregioregular polymers (depending on the configuration of the alditol) were obtained in high yields and with number‐average molecular weights within the 20,000–30,000 range. All these polyurethanes were amorphous with T_g being highly dependent on the aliphatic or aromatic nature of the diisocyanate used, but scarcely depending on the chemical structure of the alditol moiety. They were found to be stable up to near 300 °C, decomposing at higher temperatures through a complex three‐stage mechanism. Polyurethanes obtained from threitol did not show significant enhancement of hydrolytic degradability as compared with polyurethanes obtained from 1,4‐butanediol. Conversely, polyurethane prepared from xylitol and hexamethylendiisocyanate was found to be almost fully hydrolyzed in 1 month when incubated in water either at 80 °C and pH 7.4 or at 37 °C and pH 10. It was concluded that the alditol size seems to be of prime importance in determining the hydrodegradability of these sugar containing polyurethanes. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4109–4117, 2007     

Prediction of the selectivity in the recovery of transesterification reaction products using supported liquid membranes based on ionic liquids

Previously, we reported the selective simultaneous separation of the substrates and products of a transesterification reaction (vinyl butyrate, 1-butanol, butyl butyrate and butyric acid) through supported liquid membranes (SLMs) based on ionic liquids (ILs) and concluded that transport of the compounds was mainly regulated by the affinity of the ionic liquid towards each solute.