Synthesis methodology

Functional polymers are conventionally produced by two alternative routes (Co)polymerization of specifically functionalized monomers (e.g. 1-5 in Fig. 1 [21]) with suitably chosen structural monomers, or functionalization [1, 7, 22] of preformed non-fimctional polymers. 

For most scientific studies, both of these two approaches are practicable, and the choice depends on experience and availability of starting materials. For the development of technologically viable functional polymers, however, an ideally 

Examples of bnctional monomers carrying specific functional groups (1-, or general purpose activating (OAr) groups (6-7) 

The methodology of active ester synthesis, as shown in Fig. 2, is generally applicable and covers a wide range of nucleophiles, including primary, secondary and aromatic amines, primary alcohols and phenols. Thus, chemical modification d polymeric active esters (i.e. active ester synthesis) provides a single-step route for the preparation of functional polymers in general. The syntl sis of various polymer types by the active ester method is advanced in Sects. 5-7. Here, an example of a relativdy simpk fiinctional group (OH) is discussed to illustrate the versatility of the active ester method, as compared with conventional methods of polymer functionalization. 

The hydroxy group (OH) is ubiquitous for the study and development of functional polymers. Typical examples of hydroxy-bearii polymers which can be produced in a single step by active ester syntl sis are shown in Fig. 3. TIk substitution reaction proceeds quantitatively on the polymer, and the resulting hydroxy-bearing polymers are characterized by well-defined macromotecular structures. In contrast, tl introduction of OH groups into, for examfde, polystyrene by functionalization requires a minimum of 2-4 steps for different derivatives [28-34]. 

Activated acrylates (6) are obtained readily by acylation of the corresponding phenols or iV-hydroxy compounds with acryloyl diloride, acrylic anhydride or acrylic acid [21]. In the latter instance, a carbodiimide or other condensing 

Preparation ct h lroxy-bearing polymers via active ester synthesis 

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This annual volume continues the recent style of Organic Sytthae with emphasis on modem synthesis methodology There are 28 checked procedures... 

By replacing insoluble cross-linked resins with soluble polymer supports, the well-estabhshed reaction conditions of classical organic chemistry can be more readily apphed, while still fadhtating product purification. However, soluble supports suffer from the hmitation of low loading capacity. The recently introduced fluorous synthesis methodology overcomes many of the drawbacks of both the insoluble beads and the soluble polymers, but the high cost of perfluoroalkane solvents, hmitation in solvent selection, and the need for specialized reagents may hmit its apphcations. 

The synthesis of carbon templated mesoporous tin MFI catalysts with different Si/Sn was carried out using microwave and in typical synthesis methodology TEOS, TPAOH, [Sn(C5H70)2]2]Cl2, ethanol and water were employed where the molar composition of the reaction mixture was 0.06 TPAOH 0.67 H20 0.028 TEOS 1.3 g EtOH X mg of tin precursor (X = 85, 63, 42, 21 mg). This synthesis mixture was stirred for 90 min at room temperature and then Black pearl 2000 carbon (10% wt. of TEOS) was added and again stirred for 4 h vigorously. The crystallization of C-meso-Sn-Silicalite was performed in a Teflon cup placed in a microwave oven (MARS-5, CEM, maximum power of 1200 W). 

This chapter presents some examples of the asymmetric synthesis of complicated natural products. These examples will demonstrate that building up these molecules is unlikely if we do not use the asymmetric synthesis methodology. Excellent accounts by Masamune et al.1 and Noyori2 give a clear picture of the strategies for stereochemical control in organic synthesis. 

The review of Notari (33) covers the synthesis methodologies of titanium silicate molecular sieves available up to 1996. The reviews of Corma (279) and subsequently of Biz and Occelli (280) describe the synthesis of mesoporous molecular sieves. An informative article on the preparation of TS-1 was reported recently by Perego et al. (68). In this section we list some of the recent developments in the synthesis of micro and mesoporous titanosilicate molecular sieves. 

Titanosilicate Synthesis methodology, composition and improvements Si/Ti Crystallite size (nm)/ morphology References... 

Compositions of the synthesis gel and other physical characteristics of titanium silicate materials obtained in various synthesis methodologies are listed in Table Cl. 

Fig. 13.17 Shift of synthesis methodology multi-bond manipulation by multi-catalytic transformations [4],...

Finally, the reproducibility of the nanocarbons and their hybrids is of paramount importance when implementing them into commercial devices. This will require the definition of key characteristics and the development of standard synthesis methodology that will also enable better comparison of results between research groups. 

The key effect of oxide supports on the catalytic activities of metal particles is exerted through the interface between oxides and metal particles. The key objective of this study is to develop synthesis methodologies for tailoring this interface. Here, an SSG approach was introduced to modify the surface of mesoporous silica materials with ultrathin films of titanium oxide so that the uniform deposition of gold precursors on ordered mesoporous silica materials by DP could be achieved without the constraint of the low lEP of silica. The surface sol-gel process was originally developed by Kunitake and coworkers.This novel technology enables molecular-scale control of film thickness over a large 2-D substrate area and can be viewed as a solution-based... 

While these steroids can be extracted directly from human tissue, in most instances they can also be synthesized chemically. Direct chemical synthesis methodology has also facilitated the development of synthetic steroid analogues. Many such analogues exhibit therapeutic advantages over the native hormone, e.g. they may be more potent, be absorbed intact from the digestive tract, or exhibit a longer duration of action in the body. The majority of sex steroid hormones now used clinically are chemically synthesized. 

Helix induction can be augmented by mimicking natural mechanisms using a variety of synthetic expedients. In general, these approaches seek to either stabilize or mimic helix nucleation sites or to naturally or artificially secure side-chain linkages. In most cases, these transformations make use of additional synthetic procedures beyond standard peptide synthesis methodologies to juxtapose amino acids or essential elements thereof in a manner that mimics a protein helix. 

A wide choice of peptide synthesizers is currently available, ranging from manual to fully automated. They are all based on solid-phase peptide synthesis methodologies in which either f-butoxy carbonyl (t-boc) (11), or 9-fluor-enylmethoxycarbonyl (Fmoc) (12) is the major protecting group during synthesis. A detailed description of peptide synthesis is clearly beyond the scope of this chapter, and further information on practical and theoretical approaches to this chemistry may be found elsewhere (13-15). However, a brief outline of solid-phase synthesis may prove useful. 

Peptides were prepared manually by stepwise solid-phase synthesis methodology using conventional N"-Boc chemistry. Briefly, copoly(styrene/l% DVB)-pMeBHA-HCl resin, [100-200 mesh (substitution... 

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