High versatility

The highly regio- and diastereoselective addition of an alkyl and an arylthio group to an olefinic double bond ( carbosulfenylation ) is achieved with arenesulfenyl chlorides and alkyl-chloro-titanium(IV) species (Reetz reagent, from R2Zn/TiCU 5 1 M. T. Reetz, 1987, 1989), Use of the more bulky 2,4,6-triisopropylbenzenesulfenyl chloride improves the yield of the highly versatile alkyl aryl sulfide products. 

Eluidized-bed reactors are highly versatile and can accommodate many types of polymerization catalysts. Most of the catalysts used for LLDPE production are heterogeneous Ziegler catalysts, in both supported and unsupported forms. The gas-phase process can also accommodate supported metallocene catalysts that produce compositionaHy uniform LLDPE resins (49—51). 

Alkylphenol ethoxylates are chemically stable and highly versatile surfactants that find appHcation in a large variety of industrial products including acid and alkaline metal cleaning formulations, hospital cleaners, herbicides (qv) and insecticides, oil-weU drilling fluids, synthetic latices, and many others (see Disinfectants AND antiseptics Elastop rs, synthetic Insect control technology Metal surface treati nts Pesticides Petroleum, drilling fluids). 

The kieis aie of varying sizes and production units can handle from 225—1400 kg, adjusting proportionally the pump size and speed. Most machines are highly versatile so as to accommodate the kind of textile being dyed they are able to control rate of temperature rise, volume ofHquor flow, and time of dye apphcation. 

The loss of one or two (or sometimes more) ring members from heterocyclics, concerted with or followed by formation of a new ring, is a highly versatile method for heterocyclic synthesis. Loss of N2, CO, CO2, S, SO, SO2, H2C=CH2, etc. is common. Diradical or dipolar intermediates are often encountered, and valence isomerization before the actual fragmentation is characteristic for some systems. 

Acrylic and methacrylic acids and their esters are highly versatile materials in that the acid and ester side groups can partake in a variety of reactions to produce a very large number of polymerisable monomers. One particularly interesting approach is that in which two methacrylic groupings are linked together so that there are two, somewhat distant, double bonds in the molecule. In these cases it is possible to polymerise through each of these double bonds separately and this will lead eventually to a cross-linked network structure. 

Most of the reactions applied to amines can also be transferred to alcohols (Eig. 7-5). One large group of chiral alcohols are the (i-adrenoreceptor blockers, for which a variety of derivatization agents was developed. One highly versatile reagent for the separation of (i-blockers is A-[(2-isothiocyanato)cyclohexyl]3,5-dinitrobenzoyl-amide (DDITC) [11]. Alternatively, unichiral drugs such as (3-blockers or (S)-naproxen [12] may be used in a reciprocal approach to derivatize racemic amine compounds. 

There is a wide variation in properties among the over 35,0000 commercially available materials classified as plastics. They now represent an important, highly versatile group of commodity and engineering plastics. Like steel, wood, and other materials, specific groups of plastics can be characterized as having certain properties. As with other materi-... 

Burkhard P, Stetefeld J, Strelkov SV Coiled coils A highly versatile protein folding motif. Trends Cell Biol 2001 11 82. Collinge J Prion diseases of humans and animals Their causes and molecular basis. Annu RevNeurosci 2001 24 519. 

Protein phosphorylation-dephosphorylation is a highly versatile and selective process. Not all proteins are subject to phosphorylation, and of the many hydroxyl groups on a protein s surface, only one or a small subset are targeted. While the most common enzyme function affected is the protein s catalytic efficiency, phosphorylation can also alter the affinity for substrates, location within the cell, or responsiveness to regulation by allosteric ligands. Phosphorylation can increase an enzyme s catalytic efficiency, converting it to its active form in one protein, while phosphorylation of another converts it into an intrinsically inefficient, or inactive, form (Table 9—1). 

The second NIST human DNA SRM is a PCR-based DNA Profiling Standard. The PCR was first described by Saiki et al. (1985,1989). Since then it has developed into a highly versatile and widely used detection, identification, manipulation and analysis tool in molecular biology, including DNA profiling. In brief, two short synthetic oligonucleotides, or primers, are used to define an intervening DNA sequence... 

The nitroaldol reaction or Henry reaction is a powerful and highly versatile carbon-carbon bond-forming reaction, allowing a plethora of key molecular frameworks, such as p-hydroxynitroalkanes, 1,2-amino alcohols or a-hydroxy carboxylic acids to be synthesised in a straightforward manner. Therefore, the development of practical catalytic asymmetric versions of this reaction is still largely desirable. The first catalytic asymmetric nitroaldol reaction was reported in 1992, " but despite its long history, relatively few chiral ligands have... 

Even though we take a specific perspective on the topics addressed in this section, we will make an effort not to obscure two important points. First, the methods described here are highly versatile and can be used for many different problems. Second, there are deep conceptual connections between the material covered in this section and the methods described in the remainder of this chapter and in many other chapters. 

A highly versatile method for the synthesis of alkanes and other hydrocarbons from organic halides has been developed by E. J. Corey (Harvard University, Nobel Prize for Chemistry in 1990), G. H. Posner (The Johns Hopkins University), and by G. M. Whitesides (Harvard University) and H. O. House (Georgia Institute of Technology). 

A major advantage of the sequence presented here is that the aldehyde group is protected at the siloxycyclopropane stage, which allows convenient storage of this stable intermediate. Of equal importance is the valuable carbanion chemistry that can be carried out a to the ester function. Efficient substitution can be achieved by deprotonation with LDA and subsequent reaction with electrophiles.12-13-6 This process makes several a-substituted [1-formyl esters available. Other ring opening variants of siloxycyclopropanes - mostly as one-pot-procedures - are contained in Scheme I. They underscore the high versatility of these intermediates for the synthesis of valuable compounds.6 Chiral formyl esters (see Table, entries 2-5) are of special... 

Because of their high reactivity and their low steric demand, alkynes are highly versatile partners. The resulting vinylmetal species are also important reactive entities. Accordingly, the intermolecular carbopalladation of alkynes has attracted the interest of organic chemists for years.42-45... 

Nitroolefins are good Michael acceptors and their reactivity toward diethylzinc is different depending on the presence or absence of Lewis acids. Since the nitro group can be further transformed to a variety of useful containing functionalities,76,7641 the asymmetric 1,4-additions of nitroolefins may provide an easily accessible pathway to highly versatile optically active synthons. 

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