J.L. Molina

Isothiocyanato derivatives of sugars in the stereoselective synthesis of spironucleosides and spiro-C-glycosides

Abstract A stereocontrolled synthesis of pyranoid and furanoid spironucleosides and spiro- C -glycosides ( d - ribo and d - arabino configurations) of oxazolidines, oxazolines and perhydrooxazines via isothiocyanato sugar derivatives is reported. The intermediate isothiocyanates are prepared from sugar spiroketals by stereoselective opening of the acetal ring with trimethylsilyl N - and C -nucleophiles, and later formation of the isothiocyanato group.

Reactions of per-O-acetylglucosyl isothiocyanate with carbon bases. A new method for the stereocontrolled syntheses of nucleosides and glucosylaminothiophenes

Abstract Reaction of 2,3,4,6-tetra- O -acetyl-β- d -glucopyranosyl isothiocyanate 5 with diethyl malonate in a basic medium gave the corresponding glucopyranosyl thioamide without significant deacetylation. This thioamide in solution presents Z-anti as the sole configuration. Reactions of 5 with carbanions which have an ethoxycarbonyl group are a way to prepare anomerically pure N -nucleoside derivatives of pyrrole and tetrahydropyridine. Reactions of 5 with carbanions stabilized by one cyano group are used to prepare glucosylamino thiophenes with only the β-configuration. Some other stereochemical aspects of the prepared compounds are discussed.

Chiral thioxohydroimidazoles with two sugar moieties. N-, C-, and spiro-nucleosides

Abstract 2-Amino (alkyl and arylamino)-2-deoxy- d -fructose and different sugar isothiocyanates are used in the diastereoselective synthesis of chiral imidazolidine-2-thione N -nucleosides 12 – 23 . Water β-elimination of these compounds produces imidazoline-2-thione N -nucleosides 27 – 31 , whereas cyclodehydration of the same products gives, with high stereoselectivity, chiral spironucleosides with an N -glycosyl radical 34 – 37 . Conformational aspects of some of the prepared compounds are discussed.

Climatic applicability of downdraught cooling in Europe

This study describes the work on the development of climatic applicability maps of downdraught cooling in Europe; this work is presented as an extension of the work developed in the PHDC project, 2008–2010. The approach is based on a set of maps, which are based on two related climatic characteristics: dry bulb temperature–wet bulb temperature (DBT−WBT) and 25°C−WBT, and in the cooling requirements for each location. The meaning of the climatic characteristics will be explained in the text; as the first climatic characteristic represents the potential of using the evaporative systems to cool the air, and the second one shows the potential of cooling the building with a system that theoretically could supply the air in wet bulb conditions. The potential opportunity of using different types of downdraught cooling solutions, such as passive downdraught evaporative cooling and hybrid downdraught cooling, as an alternative to conventional air conditioning was assessed for different climate regions. A detailed version of a part of the Europe map will be done in order to take into account the particularities of a country like Spain. This set of maps will show the same parameters but with more resolution. Finally, six cities representing major climatic regions were selected for climatic analysis. This resulted in the identification of three climate zones for downdraught cooling application in Europe, and the suggestion of appropriate design strategies for each one of them.

Reactions of Per-O-Acetylglucosyl Isothiocyanate with Enamines. A Route for the Synthesis of Pyrimidine Nucleosides

Abstract The reaction of 2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl isothiocyanate with enamines in basic medium to form the glucosylthioamides 9-16, the glucosylthiourea 17, and the nucleoside analogue 18 is reported. The N-halogenophenyl-(1-3, 5-7) and the N-(3,4-dimethoxybenzyl)-(4,8) enaminoesters or enaminones were prepared as precursors for 9-18. The treatment of several of the prepared glucosylthioamides with thiophosgene yields dithioxopyrimidine nucleosides (19-22) with the sugar ring on position 3 of the heterocycle. Glucosylamides are isolated as byproducts. The enamino moieties of the prepared glucosylthioamides and glycosylamides have the EEE configuration and the thioamide or amide bond the Z, anti geometry.

Gestión y rehabilitación energética de edificios existentes: procedimiento experimental de diagnosis y caracterización energética

Resumen Uno de los factores esenciales para la gestion y rehabilitacion energetica de edificios existentes es establecer un procedimiento practico y eficiente, a partir del control distribuido y de la monitorizacion inteligente, tratando de automatizar los procesos de funcionamiento, conocer el estado de las instalaciones, monitorizar las variables criticas y recibir informacion on-line y off-line del rendimiento de las mismas con el fin de asegurar las condiciones de confort en un contexto de consumo de energia racional. Todo ello se concretiza en el desarrollo de un nuevo modelo para la prediccion del consumo energetico de edificios. Esta prediccion se realiza en dos niveles: horario, con un modelo derivado de las funciones de transferencia aplicadas a la edificacion, y diario, con un modelo simplificado a partir del anterior. El objetivo es conseguir un consumo inteligente de energia, y sobre todo eficiente a traves de la implementacion progresiva de medidas de ahorro de energia

Ventilación natural: estudio aerodinámico mediante CFD de extractores pasivos y captadores de viento

La ventilacion natural se ha ganado protagonismo en los ultimos tiempos como una medida de ahorro de energia para edificios. Los dos principios fundamentales de ventilacion natural son el tiro natural por diferencia de temperatura, y la fuerza del viento. El articulo pretende analizar la aerodinamica de los captadores y extractores de viento mediante fluido-mecanica computacional, optimizando las geometrias de estos elementos, y dando como producto del trabajo un modelo simplificado para poder tenerlos en cuenta el calculo aeraulico de las instalaciones de ventilacion y climatizacion de los edificios. Concretamente, se caracteriza una base de geometrias de captacion de viento, y se elabora una guia para el diseno de geometrias de extraccion ofreciendo varias de ellas como producto del trabajo realizado.In recent years, natural ventilation has won popularity as an energy saving measure for buildings. There are two fundamental principles of natural ventilation: natural draft by temperature differences, and wind force. The purpose of the article is to analyze the aerodynamics of windcatchers and wind-extractors by means of computational fluid mechanics, optimizing the geometries of these elements, and giving a simplified model as a result of the work, so as to include it in the aeraulic calculation of the buildings’ air conditioning systems. Therefore, a base for wind catching geometries has been characterized, and a guide for the design of extraction geometries has been developed; several of them are offered as a result of the work undertaken.

Natural ventilation: CFD aerodynamic study about passive extractor and windcatcher

La ventilacion natural se ha ganado protagonismo en los ultimos tiempos como una medida de ahorro de energia para edificios. Los dos principios fundamentales de ventilacion natural son el tiro natural por diferencia de temperatura, y la fuerza del viento. El articulo pretende analizar la aerodinamica de los captadores y extractores de viento mediante fluido-mecanica computacional, optimizando las geometrias de estos elementos, y dando como producto del trabajo un modelo simplificado para poder tenerlos en cuenta el calculo aeraulico de las instalaciones de ventilacion y climatizacion de los edificios. Concretamente, se caracteriza una base de geometrias de captacion de viento, y se elabora una guia para el diseno de geometrias de extraccion ofreciendo varias de ellas como producto del trabajo realizado.In recent years, natural ventilation has won popularity as an energy saving measure for buildings. There are two fundamental principles of natural ventilation: natural draft by temperature differences, and wind force. The purpose of the article is to analyze the aerodynamics of windcatchers and wind-extractors by means of computational fluid mechanics, optimizing the geometries of these elements, and giving a simplified model as a result of the work, so as to include it in the aeraulic calculation of the buildings’ air conditioning systems. Therefore, a base for wind catching geometries has been characterized, and a guide for the design of extraction geometries has been developed; several of them are offered as a result of the work undertaken.

Synthesis and Mass Spectra of Sugar Thioimidazole Derivatives

ABSTRACT The reaction of 1-halogenophenylglucofuranoimidazolidine-2-thiones (1, 2) with benzyl chloride gives bicyclic S-benzylthioimidazolines (3,4) or tetrahydroxybutyl S-benzylthioimidazoles (7, 8) depending on the presence or absence of sodium hydrogencarbonate. In the latter case a partial desulphuration takes place. The electron impact mass spectra of compounds 1-4,7,8, and of the acetyl derivatives 5,6,9, and 10 are examined. The primary fragmentations and two fragmentation pathways were observed, the importance of which depends on the cyclic character of the molecule and of the nature of the substituent (OH or OAc). Present address: Instituto de Ciencias de Materiales, Universidad de Sevilla-CSIC, and Dpto de Quimica Inorgdnica, Facultad de Quimica, Universidad de Sevilla E-41012 Seville, Spain.