The Use of Copper(I) Halides as a Preparative Tool

Mannich-type reactions are powerful methods for the efficient synthesis of beta-amino carbonyl compounds that are valuable intermediates for the construction of natural products, beta-peptides, and peptidomimetics. For the efficient steric steering of Mannich reactions a method was developed that consists in the treatment of imines with N-protected amino acid chlorides to give N-acyliminiumion intermediates that are subsequently attacked with silylketene acetals. The reactions are run best at room temperature and in the absence of any Lewis acid. The highest stereoselectivity is observed if N,N-phthaloyl tert-leucine is employed as chiral auxiliary and if N-aryl,C-aryl Schiffs bases are used that carry two ortho-substituents in either aromatic ring. Under these conditions the Mannich adducts are formed in preparatively useful yields and with excellent stereoselectivity (diastereomer ratio in general > 99:1). The chiral auxiliary group is readily removed by 1) cleavage of the phthaloyl imide via reduction with NaBH4 and acid hydrolysis followed by 2) Edman degradation

Microporous poly-N,N-dimethylacrylamide-p-styrylsulfonate-methylenebis(acrylamide): a promising support for metal catalysis

The synthesis of poly-N,N-dimethylacrylamide-p-styrylsulfonate (DMAA-SS) with 4 mol% of methylene bis(acrylamide) mol% of methylene bis(acrylamide) (MBAA) as crosslinker is described. Bulk polymerization of water solution of monomers (DMAA, SS sodium salt, MBAA) was carried out under gamma irradiation. Swellability in water and various organic solvents showed mainly hydrophilic character of the resin. The ion-exchange experiments with 1 M hydrochloric acid and with [Pd(NH3)4]2+ showed very good accessibility of the inner space of the material. Polymer supported [Pd(NH34]2+ was reduced by hydrogen in methanol, sodium borohydride in water and sodium borohydride in ethanol. Under these last conditions uniform distribution of Pd throughout the resin particles was observed. The activated material turned out to be a good catalyst for the hydrogenation of p-nitrotoluene to p-toluidine in methanol under ambient conditions

MICROPOROUS POLY-(N,N-DIMETHYL-ACRYLAMIDE)-(1-METHACRYLOYL-ETHYLENE-2-SULFONATE)-(N, N'-METHYLENE-BIS-ACRYLAMIDE) RESINS AS HYDROPHILIC SUPPORTS FOR METAL-CATALYSTS

The synthesis of poly-(N,N-dimethyl-acrylamide)-(1-methacryloyl-ethylene-2-sulphonate) (M4K) with 4 mol. % of N,N'-methylene-bis-acrylamide (MBAA) as crosslinker, and of poly-(N,N-dimethyl-acrylamide)-(1-methacryloyl-ethylene-2-sulphonic acid) (M4A) with 4 mol. % MBAA is described. Polymerization was performed under gamma rays irradiation of a water solution of monomers (M4K), or of the monomer mixture (M4A), at room temperature. High affinity to protonic solvents was observed for both materials. Palladium catalysts were prepared from M4K through ion-exchange with [Pd(NH3)4]2+ and from M4A through ion-exchange with palladium acetate; the subsequent Pd(II) reduction with sodium borohydride in ethanol yielded the final catalysts with a uniform distribution of metal throughout the resin particles. The average size of metal crystallites obtained by X-ray diffraction was about 4 nm and did not show any dependence on metal content in the polymer in the range from 0.5 to 8.8 w/w % of metal. The rate of hydrogenation of p-nitrotoluene and cyclohexene in catalytic tests with 1 and 0.5 w/w % Pd catalysts was proportional to the metal content in catalysts, which confirmed a very good accessibility of these supports. Catalysts with low metal content also exhibit a significant deactivation in the course of the hydrogenation of p-nitrotoluene to p-toluidine in methanol under ambient conditions

Um método quantitativo para avaliação da satisfação dos clientes

Há premência em se sistematizar esquemas para extrair informações dos novos indicadores que estão sendo empregados nos modernos métodos de avaliação do desempenho operacional das empresas. Na ampla maioria destes, a perspectiva do cliente é sempre levada em consideração. Entretanto, as pesquisas junto a eles sempre fornecem informações qualitativas, embora constituam uma das áreas mais atuantes das empresas de pesquisa de mercado. Enfrentando o desafio de generalizar um modelo contábil para incorporação da avaliação quantitativa de ativos intangíveis de empresas que seja útil para a moderna caracterização dos seus desempenhos operacionais, propõe-se neste trabalho um esquema inovador para avaliar a satisfação dos clientes capaz de fornecer resultados quantitativos inequívocos. Os indicadores que o método proposto utiliza provêm de enquêtes bem definidas, realizadas junto aos clientes, e possibilitam o advento de índices que caracterizarão ativos e passivos das empresas relativos à satisfação dos clientes.<br>It is a matter of certain urgency to formalize rules with a view to extracting information from the new indicators that are used in modern enterprise evaluation methods. In most situations, the client's point of view is always taken into consideration. However, in spite of being one of the most active areas for market research companies, client inquiries always provide qualitative information. Facing the challenge of generalizing an accounting model that incorporates the quantitative evaluation of companies' intangible assets so as to be useful for improving their performance, this paper proposes an innovative method for evaluating client satisfaction. The elements used in this new method come from inquiries that are regularly held among clients. The obtained results provide the calculation of indices that characterize companies' assets and liabilities and are related to client satisfaction

Performance management in construction : a conceptual framework.

This paper presents a review of the literature on performance management and measurement in various industries with the aim of transferring best practice into construction. A framework is presented which ensures that effective strategies are deployed to form the performance management system that construction organizations can adopt. The performance measurement process (conceptual) framework (PMPF) adopts the balanced scorecard (BSC) with the addition of a number of elements and perspectives. It rationalizes the relationships between performance measures and goals derived from strategy, so the impact of those measures on an organization's performance can be examined and analysed to indicate potential areas for improvemen