Strategies for preparation

The strategy for preparing gold catalysts for liquid-phase oxidation is based on environment friendly and cheap methodologies with the aim to produce 3-5 nm particles, well dispersed on carbon supports, to be applied also to large-scale preparations. 

Diastereoselective intramolecular cycloaddition of nitrones is useful for constructing nitrogen- containing cyclic structures. The reaction serves as a key step in a number of natural product syntheses.63 Tufarriello and coworkers have used this strategy for preparing cocaine and other alkaloids.74 As a classical example, enantioselective total synthesis of (+)-luciduline is presented in Scheme 8.13, in which a useful feature of the 1,3-dipolar addition of nitrones is nicely illustrated.75... 

Two strategies for preparation of neutral and monocationic porphyrin models were used. The presence of a spacer arm directly attached to the meso phenyl position of the porphyrins gave access to a series of dimers with different substituents on the meso position and with different geometries. 

Generally, the above three methods are effective synthetic and modification strategies for preparing soluble Pcs and tuning their properties. In the actual process of synthesizing soluble Pcs, the most effective strategy is certainly the combination of all the three methods and many Pcs have actually been synthesized based on this consideration [73-77]. 

The number of publications concerning utilization of the EISA process for fabrication of different structured materials is counted in the hundreds, which is far beyond the possibilities of this chapter to review in depth. Rather, we intend to provide a brief introduction into EISA and its application to the fabrication of functional thin films for electronic applications (e.g., electro-chromic layers and solar cells), with a special focus on fabrication of crystalline mesoporous films of metal oxides. Attention will also be given to techniques used to evaluate the pore structure of the thin films. For the other aspects of the EISA process, for example its mechanism,4 strategies for preparation of crystalline porous metal oxides,5 mesoporous nanohybrid materials,6 periodic organic silica materials,7,8 or postgrafting functionalization of mesoporous framework,9 we kindly recommend the reader to refer to the referenced comprehensive reviews. 

Scheme 5.27 NPOE-based strategy for preparation of P-mannosides.

We have demonstrated an orthogonal protection/deprotection strategy for preparing a carbohydrate core that could be iteratively deprotected and glycosylated to form... 

The major synthetic strategies for preparing homopolyatomic cations of group 16 elements can be summarized as follows ... 

Tkac J, Ruzgas T (2006) Dispersion of single walled carbon nanotubes. Comparison of different dispersing strategies for preparation of modified electrodes toward hydrogen peroxide detection. Electrochemistry Communications 8 899-903. 

The use of appropriate reference materials should be a key feature of the quality assurance/quality control structure in any future ocean science project involving chemical measurement. Reference materials use should be explicitly addressed in the project planning stages, proposals, and publications. In the event that appropriate reference materials are not already available, the committee recommends that the proposed project develop a strategy for preparation to assure the ultimate value of measurements made as part of the research. 

The transformation from spheres to cyhnders is a peculiar example for the self-adjustment of the molecular conformation. The switching shape can be regarded as an example for the principle of quasi equivalency established by A. Klug for the self-assembly of biomolecules and viruses [145] for the sake of an improved intermolecular packing, the molecules adopt a conformation different from the minimum energy one. This also demonstrates that shape control does not mean a fully constrained structure. Similar to biomolecules, the combination of flexible macromolecules and self-assembly principles is a powerful strategy for preparation of molecules with well-defined but switchable shape [23]. 

Hirsch T, Kettenberger H, Wolfbeis OS, Mirsky VM. A simple strategy for preparation of sensor arrays molecularly structured monolayers as recognition elements. Chem Commun 2003 432-433. 

The usual strategies for preparing homogeneous samples of known stoichiometry when one or more constituent is volatile is to maximize the atomic scale mixing of constituents and minimize reaction times and temperatures. 

This section outlines useful strategies for preparing aldehydes and hy-droxamic acids that were developed on SynPhase crowns. 

Strategies for preparing mixed, acyclic acetals on insoluble supports include the oxidative haloalkoxylation of support-bound enol ethers (Entry 6, Table 6.1) and the acid-catalyzed reaction of alcohols with resin-bound enol ethers [627]. Alternatively, resin-bound a-chloro ethers can be converted to mixed acetals by reaction with alcohols or phenols in the presence of strong bases (KO/Bu, HOfBu, DMF, 5 h) [550,628]. Polystyrene-bound a-(phenylseleno)ethers react with aliphatic alcohols under slightly acidic conditions (NIS, TfOH, DCM/dioxane (1 1), 0°C to 20 °C, 1 h) to yield mixed, acyclic acetals [628],... 

The most commonly used strategies for preparing ureas on insoluble supports are outlined in Figure 14.2. The reaction conditions are similar to those used in solution as most of the reagents required are compatible with the widely used polymeric supports. 

Rice, K.G. (2000) Derivatization strategies for preparing N-glycan probes. Anal. Biochem., 283, 10-16. 

One of the most common strategies for preparation of carboxylic acid derivatives is the acylation of nucleophiles of general formula RXH (X = NR, O, S). If the right reaction conditions are chosen and if the product is stable these reactions usually proceed swiftly and in high yield. Some carboxylic acids and nucleophiles, however, do not react smoothly or lead to unexpected results. The following sections cover a selection of representative examples of problematic starting materials. 

An alternative strategy for preparation of monoacylated 1,2- and 1,3-diols is oxidative deavage of cyclic acetals prepared from a diol and an aliphatic or aromatic aldehyde (Scheme 10.7). For this purpose the required acetal does not need to be isolated, but can be generated in situ [25]. Acetals prepared from strongly electrophilic aldehydes, for example nitrobenzaldehydes, will, however, usually be difficult to oxidize (and to hydrolyze). 

New strategies for preparing either 1,2-cis- or 1,2-trans-glycosides stereoselectively have been reported.61 A chiral auxiliary containing a nucleophile is used to control the anomeric selectivity of the glycosylation. A sample reaction is shown in Scheme 8. 

Strategies for preparation of iminosugars from selectively activated aldonolactones... 

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