Superbase promoted synthesis of dienamides as useful intermediates for the synthesis of α-ketoamides, γ-lactams and cyclic imino ethers

Alkoxydienamides 2 have been synthesized exploiting the reactivity of α,β-unsaturated acetals 1 with isocyanates in the presence of Schlosser's superbase LIC-KOR. In a mild acidic medium, 2 can then be promptly converted both into α-ketoamides 3 and into substituted 2-pyrrolidinones 4 or imino ethers 5 by choosing the appropriate experimental conditions.     

Solid-phase synthesis of arginine-based double-tailed cationic lipopeptides: potent nucleic acid carriers

Herein we report a highly-efficient solid-phase strategy for the modular synthesis of 63 double-tailed lipid-peptide conjugates and their application in DNA delivery.     

Regioregular poly[3‐(4‐alkoxyphenyl)thiophene]s

An easy synthetic procedure for soluble poly[3‐(4‐alcoxyphenyl)thiophene]s is reported. The polymers present a high regioregularity degree as determined by both UV–vis spectra and ¹H and ¹³C NMR analysis. Furthermore, X‐ray powder diffraction analysis performed on films of the polymers suggests a π‐stacked packing structure of the macromolecules. Electrical characterization was performed on one of the synthesized polythiophenes on both undoped and doped (with FeCl₃ or iodine) films. The conductivity and charge‐carrier mobility were assessed by current–voltage and field effect measurements. Well‐structured polymer films were obtained simply via spin coating from chloroform solutions and without the need of further processing, unlike other regioregular polythiophenes reported in the literature. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1758–1770, 2007     

Thermal properties of poly(alkylene dicarboxylate)s derived from 1,12‐dodecanedioic acid and even aliphatic diols

A series of new aliphatic polyesters derived from 1,12‐dodecanedioic acid and different diols with an even number of methylene units have been studied to assess the effect of the chemical structure on the final thermal properties of the materials. The polyesters have high thermal stability and are fast crystallizing polymers, with crystallization rate similar to that of polyethylene (PE). This behavior is connected to the fact that long aliphatic chains assume conformational characteristics very similar to that of PE. However, the polyester prepared from ethanediol shows a peculiar behavior (for example, double melting peak, melting and crystallization temperatures, which do not fit the trend of those of the other samples and ringed spherulites) owing to a probable different conformation, deviating from the all‐trans planar typical of PE. In the isothermal crystallization studies, a bell‐shape trend has been found for the crystallization rate as a function of the number of ? (CH₂)? units in the diol. The high crystallization rate of the sample with long ? (CH₂)? sequences has been attributed to the high chain flexibility and, thus, high mobility in the molten state and ease of chain folding. By reducing the aliphatic sequence length, instead, implications of the structural characteristics of the samples are probably involved. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1053–1067, 2007     

Rapid microwave assisted esterification method for the analysis of poly-3-hydroxybutyrate in Alcaligenes latus by gas chromatography

In the present study, we used microwave energy instead of conventional heating to transform poly-3-hydroxybutyrate (PHB) into methyl 3-hydroxybutyrate (Me-3HB) in acidified methanol (H2SO4, 10%, v/v) mixture in less than 4 min at 10% microwave power. The microwave assisted method was then applied to analyze PHB produced by Alcaligenes latus. The PHB content in the biomass determined using microwave heating was comparable to the amount found by conventional heating. Moreover, the new esterification method was at least 50 times faster than the conventional method, affording a significant saving of time and energy.     

Variable annuities: A unifying valuation approach

Life annuities and pension products usually involve a number of guarantees, such as minimum accumulation rates, minimum annual payments or a minimum total payout. Packaging different types of guarantees is the feature of so-called variable annuities. Basically, these products are unit-linked investment policies providing a post-retirement income. The guarantees, commonly referred to as GMxBs (namely, Guaranteed Minimum Benefits of type ‘x’), include minimum benefits both in the case of death and survival. In this paper we propose a unifying framework for the valuation of variable annuities under quite general model assumptions. We compute and compare contract values and fair fee rates under ‘static’ and ‘mixed’ valuation approaches, via ordinary and least squares Monte Carlo methods, respectively.     

A comparison of numerical integration rules for the meshless local Petrov–Galerkin method

The meshless local Petrov–Galerkin (MLPG) method is a mesh-free procedure for solving partial differential equations. However, the benefit in avoiding the mesh construction and refinement is counterbalanced by the use of complicated non polynomial shape functions with subsequent difficulties, and a potentially large cost, when implementing numerical integration schemes. In this paper we describe and compare some numerical quadrature rules with the aim at preserving the MLPG solution accuracy and at the same time reducing its computational cost.     

Variational approach for a general financial equilibrium problem: The Deficit Formula,the Balance Law and the Liability Formula. A path to the economy recovery

Without using a technical language, but using the universal language of mathematics, we provide simple but significant laws, as Deficit Formula, Balance Law and Liability Formula, for the management of the world economy. Decisions, under these laws, for the recovery of the economy and for the good governance clearly appear. Further a simple but useful economical indicator E(t)$E(t)$ is provided and the results are illustrated with a significant example.     

Comparative analysis of different plant oils by high-performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry

This work focused on the way several electrolyte components could affect the electroosmotic flow and the capillary electrophoretic migration of aliphatic or aromatic (hydroxy)carboxylic acids. The effects exerted by the electroosmotic flow modifier, hexadecyltrimethylammonium bromide, the addition of metal salt to the electrolyte and the absorbance provider (chromophore) used for indirect detection were investigated. A retention of the organic acids was demonstrated. Its magnitude was shown to depend on the amount of cationic surfactant adsorbed onto the capillary walls. The addition of sodium nitrate led to a remobilization of all the acids except glycolic acid. Moreover, the presence of the chromophore was shown to influence mainly the migration of the glycolic acid.     

(Z)-1-Aryl-1-haloalkenes as intermediates in the Vilsmeier haloformylation of aryl ketones

[reaction: see text] Vilsmeier reagents give (Z)-1-aryl-1-haloalkenes from aryl ketones bearing an electron-donating substituent at the ortho- or para-position. These haloalkenes are intermediates in the Vilsmeier haloformylation of the aryl ketones. Another reaction mechanistic pathway is thus available in certain Vilsmeier haloformylations, in competition with the commonly accepted route by way of an enaminoketone.