Selective modification

Introduction and general overview of cyclodextrin chemistry 98CRV1743. Methods for selective modifications of cydodextrins 98CRV1977. 

Improving FCC unit profitability requires operating the unit against as many constraints as possible. Additionally, selective modifications of the unit s components will increase reliability, flexibility, and product selectivity, and reduce emissions. 

It was found that both the catalytic rates and the selectivity to the various products can be altered significantly (rate changes up to 250% were observed) and reversibly under NEMCA conditions. Depending on the product, electrophobic or electrophilic behaviour is observed as shown in Fig. 8.57. In addition to the selectivity modification due to the different effect on the rate of formation of each product, acetaldehyde, which is not produced under open circuit conditions is formed at negative overpotentials (Fig. 8.58). Enhancement factor A values up to 10 were observed in this complex system.59... 

Methane oxidation and partial oxidation, electrochemical promotion of, 308 dimerization, 470 reforming, 410 Methanol dehydrogenation electrochemical promotion of, 403 selectivity modification, 404 Methanol oxidation electrochemical promotion of 398 selectivity modification, 400 Microscopy... 

Site-Selective Modification of the Nanoscale Surface Morphologf 211... 

Site-Selective Modification of the Nanoscale Surface Morphology of Dye-Doped Copolymer Films Using Dopant-Induced Laser Ablation... 

Wang, Z., Masuo, S., Machida, S. and Itaya, A. (2005) Application of dopant-induced laser ablation to site-selective modification of sea-island structures of polystyrene-fclock-poly(4-vinylpyridine) films. Jpn. J. Appl. Phys., 44, L402-L404. 

Define the analytical approach, such as the material and the analytes to be looked for so as to (possibly) answer the questions asked and to solve the problems. Select an appropriate analytical method, with definition of its purpose and utility. If none of the available methods fits the analytical purpose, try to deduce method approach(es) from existing methods for structurally related compounds or materials by introducing carefully selected modifications and adaptations. 

Moreover, the stability of the QM pincer complexes allows selective modifications of both the metal center and the carbonyl part of the quinone methide moiety, still with... 

The starting point for much of the work described in this article is the idea that quinone methides (QMs) are the electrophilic species that are generated from ortho-hydro-xybenzyl halides during the relatively selective modification of tryptophan residues in proteins. Therefore, a series of suicide substrates (a subtype of mechanism-based inhibitors) that produce quinone or quinonimine methides (QIMs) have been designed to inhibit enzymes. The concept of mechanism-based inhibitors was very appealing and has been widely applied. The present review will be focused on the inhibition of mammalian serine proteases and bacterial serine (3-lactamases by suicide inhibitors. These very different classes of enzymes have however an analogous step in their catalytic mechanism, the formation of an acyl-enzyme intermediate. Several studies have examined the possible use of quinone or quinonimine methides as the latent... 

The successful selective modification of the cycloamyloses must overcome rather severe synthetic difficulties derived primarily from the multiplicity of potentially reactive cycloamylose hydroxyl groups. Utilizing techniques developed for the modification of acyclic carbohydrates, the cycloamyloses... 

Yamada, H., Imoto, T., Fujita, K., Okazaki, K., and Motomura, M. (1981) Selective modification of aspartic acid-101 in lysozyme by carbodiimide reaction. Biochemistry 20, 4836M842. 

Another convenient entry to fused cyclobutene-1,2-diesters was via site selective modification of the norbomene rt-bond in Smith s fe-alkene 49, e.g. treatment with 3,6-di(2 -pyridyl)-s-tetrazine 51 followed by DDQ oxidation afforded the cyclobutene-derivative 53 <97AA119>, while direct coupling with 3,5-f> (trifluoromethyl)-l,3,4-oxadiazo]e 54 furnished the tas(cyclobutene-l,2-diester) 55 (Scheme 6) <97SL196>. 

The selective modification of reactive side chains within proteins with compounds containing NMR-sensitive isotopes offers an alternative route to the labeling of proteins. The chemical modification of side chains with reagents labeled with NMR-sensitive isotopes may permit detailed structural and dynamic questions to be addressed, although perturbations of the system caused by the labeling may be of concern in cases where the chemical identity... 

Ferrero, M. and Gotor, V., Biocatal3ttic selective modifications of conventional nucleosides, carbocyclic nucleosides, and C-nucleosides. Chem. Rev., 2000,100, 43194-347 and references cited therein. 

Grob, C. and Wortberg, J., Optimizing Purging Time at Product Change in Blown Film Extrusion by Selective Modification of Process Parameters, SPE ANTEC Tech. Papers, 50, 261 (2004)... 

By selective modification of the serine 221 at the active site of the protease sub-tilisin Carlsberg to its seleno derivative, peroxidase activity was achieved and utilized for the enantioselective reduction of hydroperoxides (Table 6). In con-... 

Selective modification of polyols such as ethylene glycol, 1,3-propylene glycol, or glycerol with butadiene (1) has been studied [7-10]. The monosubstituted compounds are preferred due to their potential applications as surfactants, PVC plasticizers, or even in cosmetics. The telomerization of 1 with ethylene glycol yields a complex mixture including linear and branched mono- and ditelomers, as well as 1,3,7-octatriene and vinyl cyclohexene (Fig. 2) [11]. 

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