Synthesis of polyacetylenic acids isolated from Heisteria acuminata

Four linear polyacetylenic compounds were synthesized. Pentadeca-6,8,10-triynoic acid 1 and octadeca-8,10,12-triynoic acid 2 were synthesized by using acetylene coupling reactions. The syntheses of (Z)-hexadec-11-en-7,9-diynoic acid 3 and (Z)-octadec-12-en-7,9-diynoic acid 4 by using vinylic telluride coupling reactions were accomplished.     

The region of attainability of nonlinear systems with unbounded controls

In this work, we give a characterization of the topological boundary and the interior of the reachable set for a family of vector fields of the formX ⁰+aX ⁱ , wherea andi belongs to an arbitrary set of indices. The methods considered in this article are applied to various problems in control theory.The authors wish to express their gratitude to Professor Felix Albrecht for his precious comments on the first version of this work.     

Synthesis of dihydrofuran rings using α‐substituted β‐ketoamides

In this paper is described an unreported method employing α‐alkenyl β‐ketoamides as starting material to give 2,3‐dihydrofurans, precursors of substituted furans.     

Synthesis and functionalization of N-sulfinyl imines: Sonogashira reaction and copper-catalyzed azide-alkyne cycloaddition

A small library of novel molecules was generated using a rapid and efficient methodology for the synthesis of N-sulfinyl imine triazole compounds. The process involves a coupling step from the Sonogashira cross-coupling reaction and then, in a one-step reaction, deprotection of the trimethylsilyl group and triazole heterocyclic ring formation using a microwave reactor.     

One-pot three-component synthesis of indole-3-glyoxyl derivatives and indole-3-glyoxyl triazoles

A general and efficient reaction of indole with oxalyl chloride and nucleophiles providing indole-3-glyoxyl derivatives has been developed in mild conditions. In the same fashion, the other reaction involved the addition of organic azides leading to the synthesis of indole-3-glyoxyl-1,2,3-triazoles, which proceeds smoothly generating the products in moderate to high yields.     

Non-isothermal crystallization of MaterBi-Z/clay nanocomposites

Non-isothermal crystallization of MaterBi-Z (starch-polycaprolactone blend) and its nanocomposites with different clay contents (0, 2.5 and 5 mass%) was studied. The experimental data show that clay can be act both as nucleating or retarding agent depend on the clay content. Kinetic parameters obtained by using a non-linear regression method, i.e., Kamal’s model and Dietz’s modification, were able to describe the non-isothermal crystallization behavior of the studied materials. A full model that takes into account the induction and growth of the crystal during cooling under non-isothermal conditions was used to obtain a continuous cooling transformation diagrams.     

Seleno and Telluro Cyclofunctionalization of α,γ-Diallyl-β-ketoesters: Polysubstituted Furan Derivatives

Seleno- and telurocyclofunctionalized furan derivatives were prepared by reaction of phenylselenenyl bromide and p-methoxyphenyl tellurium trichloride with α,γ-diallyl-β-ketoesters in good yield.     

Chemical and physical analysis for the improvement of the dry mounting method for fragile documents

Paper lamination is a widely used method to consolidate fragile documents. Previous studies have presented a new method of lamination that allows the consolidation of documents before undertaking aqueous treatments. In this method a thin Japanese paper coated with an acrylic resin is applied on the fragile document by means of a heated press. In this work we optimised the preparation of the lamination sheets as well as the working procedures, and we were able to establish that our laboratory-made specimens are chemically stable, easily reversible and permeable to aqueous solutions. The latest property is of particular importance, since it allows a subsequent aqueous deacidification even for fragile documents. The laminated paper documents were further analysed by means of colorimetry and FTIR spectroscopy before and after accelerated ageing as well as by determination of the alkali reserve left on the coated paper, in order to compare our lamination method with other commercially available lamination sheets.     

Minicomputer-based instrumentation for electroanalytical techniques

The system comprises a PDP 11/23 PLUS (16-bit) computer and a home-made electrochemical interface which includes digital/analog and analog/digital conversion circuits, a potentiostat, and programmable timers allowing fast data transfer. The software developed includes operating system routines and user-level programs for cyclic voltammetry and chronoamperometry. The whole system provides the user with a computer-aided execution of experiments, including potential waveform synthesis and collection and evaluation of responses.