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The objective of this study was to develop a new drywall wood-based particleboard as an alternative to gypsum board. Various development iterations have led to the use of wood particles, steatite powder and Portland cement. The resulting outcome shows that screw withdrawal resistance was improved by 37% and bending properties by 69% compared to gypsum board of a similar density (0.68&ndash, 0.70). The raw surface of the boards is of good quality and comparable to the paper-faced surface of gypsum board. Furthermore, the reaction to fire was evaluated through bench-scale test with a cone calorimeter. The investigated particleboard did not reveal visual signs of combustion after 20 min when exposed to a radiant heat of 50 kW/m2, while burning of the overlay paper of gypsum board occurred at about 57 s, suggesting that wood-cement-steatite powder particleboard could be classified as a quasi non-combustible material.

The aim of this study was to consider the use of biomass wood ash as a partial replacement for cement material in wood-cement particleboards. Wood-cement-ash particleboards (WCAP) were made with 10%, 20%, 30%, 40%, and 50% of wood ash as a partial replacement for cement with wood particles and tested for bending strength, stiffness, water absorption, and thermal properties. Test results indicate that water demand increases as the ash content increases, and the mechanical properties decrease slightly with an increase of the ash content until 30% of replacement. On the other hand, the heat capacity increases with the wood ash content. The WCAP can contribute to reducing the heat loss rate of building walls given their relatively low thermal conductivity compared to gypsum boards. The replacement of cement to the extent of approximately 30% by weight was found to give the optimum results.

Legal documents play an important role in the legal systems of every nation. In order to process information automatically and make use of knowledge from legal documents, we need an appropriate knowledge representation for them. In this research, we investigate properties of the Vietnamese legal document system and propose a representation for the documents and their interrelationships. The main challenges for this task are their unstability, limited validity period and complicated interrelationships. Properties and relationships which we design to represent in our knowlege base are selective in order to make use of information within legal documents. In order to represent our knowlege base, we compare three methods: Semantic Network, Production Rules, Frame Language and make use of their advantages in our representation. Moreover, we implement a service-oriented system providing knowledge querying service for other application systems based on our research result.

Chelation provides a powerful means of stereocontrol in alkylations of metalated nitriles. Doubly deprotonating a series of cyclic beta-hydroxynitriles triggers cyclizations that implicate metalated nitrile intermediates having configurations imposed by chelation with an adjacent, chiral lithium alkoxide. Identifying chelation as a general stereocontrol element explains several previously anomalous alkylations of metalated nitriles and provides a potential solution to the long-standing difficulty of synthesizing trans-hydrindanes. Employing chelation to control the metalated nitrile geometry permits selective cyclizations to cis and trans hydrindanes and decalins and provides key insight into the geometrical requirements of these demanding cyclizations.

Magnesiumverbindungen spielen eine zentrale Rolle in der praparativen organischen und metallorganischen Chemie. Seit kurzem ermoglicht der Halogen-Magnesium-Austausch den Zugang zu einer Reihe funktionalisierter Grignard-Reagentien. Ester-, Nitril-, Iod- und Iminfunktionen und sogar Nitrogruppen konnen in einer breiten Reihe aromatischer und heterocyclischer Organomagnesiumverbindungen vorhanden sein. Auch hoch funktionalisierte Alkenylmagnesiumspezies konnen auf diese Weise generiert werden. Diese neuen Entwicklungen sowie die Anwendung von Organomagnesiumreagentien in Kreuzkupplungen und Aminierungsreaktionen werden in diesem Aufsatz eingehend beschrieben.

Organomagnesium reagents occupy a central position in synthetic organic and organometallic chemistry. Recently, the halogen-magnesium exchange has considerably extended the range of functionalized Grignard reagents available for synthetic purposes. Functional groups such as esters, nitriles, iodides, imines, or even nitro groups can be present in a wide range of aromatic and heterocyclic organomagnesium reagents. Also various highly functionalized alkenyl magnesium species can be prepared. These recent developments as well as new applications of organomagnesium reagents in cross-coupling reactions and amination reactions will be covered in this Review.

The reaction of β,β-dibromo or diiodo unsaturated esters with i-PrMgCl (1 equivalent) in diethyl ether allows the generation of functionalized alkenylmagnesium carbenoids which react with retention of configuration with various electrophiles providing polyfunctionalized unsaturated esters and lactones. By using two equivalents of i-PrMgCl, a 1,2-migration with retention of configuration occurs in diethyl ether allowing a new synthesis of tetrasubstituted esters and lactones.

A general preparation of alkenylmagnesium derivatives bearing an electron-withdrawing function in the α-position (Y=CN, CO2R, CONR2, SO2Ph) has been made possible by using a low temperature (−40 to −30°C) bromine–magnesium exchange with i-PrMgBr in THF. This reaction has also been used to prepare 5-magnesiated-1,3-dioxin-4-one derivatives bearing an alkoxy substituent in β-position to the carbon–magnesium bond.

Functionalized magnesium reagents have been prepared via an iodine-magnesium exchange. These reagents can be either trapped directly with aldehydes or transmetallated to copper or zinc to participate in cross-coupling reactions. The iodine-magnesium exchange, represent a unique method for the preparation of aryl and heteroaryl magnesium reagents.

5-Magnesiated-1,3-dioxin-4-ones have been prepared by performing a low temperature iodine–magnesium exchange reaction. These alkenylmagnesium reagents bearing an alkoxy function in the β-position react directly with aldehydes or with other electrophiles such as acid chlorides, allylic bromides, aryl and alkenyl iodides in the presence of a copper or palladium transition metal catalyst.

Sequential addition of i-PrMgCl and BuLi to sp3 hybridized iodoalcohols triggers a facile iodine-metal exchange. Intercepting the resulting cyclic Grignard reagents with a slight excess of an electrophile leads to a diverse range of substituted alcohols. The iodine-magnesium exchange strategy is effective with 3-carbon iodoalcohols bearing alkyl substitutents on the carbinol or adjacent carbons and with the chain-extended homolog 4-iodobutan-1-ol.

5-Magnesiated-1,3-dioxin-4-ones have been prepared by performing a low temperature iodine–magnesium exchange reaction. These alkenylmagnesium reagents bearing an alkoxy function in the β-position react directly with aldehydes or with other electrophiles such as acid chlorides, allylic bromides, aryl and alkenyl iodides in the presence of a copper or palladium transition metal catalyst.

A dry two-necked flask equipped with a magnetic stirring bar and a septum was charged with the cis-2-iodo-cyclopropanecarboxylic acid ethyl ester 1 (1 mmol) in dry THF (4 mL) under argon. The reaction mixture was cooled to —40 C and a solution of iPrMgCl (0.67 mL, 1.62 M in THF, 1.1 mmol) was slowly added. After 15 min of stirring, the exchange was complete (checked by GC analysis). Electrophile (1.5 mmol) was added and the reaction mixture was allowed to warm up to rt. After 2 h, the reaction mixture was quenched with sat. NH4Cl-solution (10 mL) and extract with ether. The organic layer was washed with brine, dried over MgSO4 and concentrated under vacuum. The crude residue was purified by flash chromatography using the specified solvent system.

Functionalized alkylmagnesium reagents bearing an acetal, a ketal, an ester, or a pyridine ring were prepared by an I/Mg-exchange using iPr2Mg·LiCl or ClMg(CH2)5MgCl·2LiCl starting from functionalized primary alkyl iodides.

Sequential addition of i-PrMgCl and BuLi to sp3 hybridized iodoalcohols triggers a facile iodine−metal exchange. Intercepting the resulting cyclic Grignard reagents with a slight excess of an electrophile leads to a diverse range of substituted alcohols. The iodine−magnesium exchange strategy is effective with 3-carbon iodoalcohols bearing alkyl substitutents on the carbinol or adjacent carbons and with the chain-extended homolog 4-iodobutan-1-ol.

Functionalized alkylmagnesium reagents bearing an acetal, a ketal, an ester, or a pyridine ring were prepared by an I/Mg-exchange using iPr2Mg·LiCl or ClMg(CH2)5MgCl·2LiCl starting from functionalized primary alkyl iodides.

Highly functionalized Grignard-reagents can be easily obtained by an iodine­magnesim exchange reaction and further reacted with various electrophiles. Via a B­Zn exchange reaction, a formal Michael addition with umpolung of the reactivity can be achieved. Chiral phosphine ligands can be easily synthesized by a 2.3 sigmatropic rearrangement and used successfully in asymmetric synthesis.