Phase target molecule synthesis

T distortions, external fields 489 Tait equation, phase transitions 370 target molecules, synthesis 91 target structures, building blocks 98 TBBA, difiusion 590 TBDA, volume/density changes 336 temperature control, X ray experiments 633 temperature dependence... 

Phase-Tranter Catalysis in Target Molecule Synthesis 1371... 

Amines are both valuable synthetic intermediates and interesting target molecules. A number of solid-phase syntheses have been developed, most of which are also suitable for the automated, parallel synthesis of this class of compound. 

Compounds containing phosphorus can be both valuable synthetic intermediates and target compounds of solid-phase synthesis. Important synthetic intermediates include phosphonium salts and phosphorus ylides, which are key intermediates in carbonyl olefinations. Their preparation is discussed in Section 5.2.2.1. The preparation of oligonucleotides, these being the most important phosphorus-containing target molecules in solid-phase synthesis, is considered in Section 16.2. In this chapter, the preparation of phosphines, phosphonic acid derivatives, and phosphinic acid derivatives is discussed. 

To enable a covalent labeling of target molecules, the dyes are functionalized with reactive groups. These are either phosphoramidites for the labeling of synthetic oligonucleotides (solid-phase synthesis), or uridine-5 -triphosphates for enzymatic coupling in PCR (random primed labeling... 

The solid-phase synthesis of organic compounds requires a linkage element which acts as a tether to the polymeric support. In a multi-step synthesis the linker must be stable towards all reaction conditions used, but should easily and quantitatively be cleaved to release the target molecule without any degradation of the latter. 

This mode of separation, as the name suggests, uses stationary phases with a special affinity for a specific analyte. The affinity ligand immobilized on the stationary phase varies dramatically from peptide, to protein, to oligonucleotide, to monoclonal antibody. In some cases the target molecule is labelled with an affinity tag to simplify the separation. This approach is common in the synthesis of recombinant proteins where the system can be engineered so that the target biomolecule expresses a tag such as polyhistidine. A stationary phase functionalized with aminodiacetic acid and nickel chelate is then used to fish out the required molecule by chelating with the polyhistidine tag. 

Avoid using solvents, separation agents, or other auxiliary chemicals. If these chemicals are necessary, then use innocuous chemicals. In the manufacture, processing, and use of chemicals, auxiliary substances are utilized at every step. An auxiliary substance aids in the manipulation of a chemical or chemicals, but it is not an integral part of the target molecule itself. This is the case of solvents and separation agents. Solvents play many crucial roles in the synthesis of chemical products. Those most evident are as reaction media and as factors in product separation and purification (i.e., solvents for recrystallization, mobile and stationary phases for chromatographic separations, and the like). 

The tedious purification of intermediates in classical solution synthesis produces pure compounds, which are then carried forward to the subsequent steps of the synthetic scheme. When a side product of the SP reaction remains attached to the resin, it becomes impossible to separate it from the desired intermediate/target molecule, thus irreversibly affecting the quality of the synthesis and the purity of the final product. This and other factors, which will be discussed in the following chapters, are considered during the so-called chemistry assessment phase of the synthesis in which the... 

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