Specific reagents, reaction types

Reagents for detection of specific residues in peptides. Many reagents give specific color reactions with certain types of residues in peptides. Among the more useful of these are ... 

The second large reaction database is Chemical Abstracts from the American Chemical Society, accessed most often via the Scifinder interface. It basically suffers from the same limitations as mentioned above. The main advantage of Scifinder for combinatorial chemists is the ability to also search for keywords. Thus, a search for a specific reaction type combined with keywords such as solid phase or immobilized reagent often leads to useful literature citations. 

Among the large number of site-specific reagents described in the literature, there are characteristics that are particularly desirable. In addition to structural similarity to the substrate or regulatory compound and the potential to react with many types of amino acids, these characteristics include water solubility, ease of synthesis, acceptable stability in aqueous solution over a moderate pH range, and the ability to form a stoichiometric, stable, isolable, and readily identifiable product from the reaction with enzyme. In this chapter, several chemical classes of affinity labels are considered, their notable features are evaluated in terms of these criteria, and selected examples of their application are presented. 

The purpose of this appendix is to survey chiral auxiliaries, solvents, reagents, and catalysts which are often used in stereoselective bond-forming reactions, thus avoiding repetition of details on the synthesis of these compounds in the other sections of Houben-Weyl Volume E21 which discuss specific reaction types. It will not contain every chiral compound ever used in asymmetric synthesis, but will focus on compounds mentioned in this Houben-Weyl volume. Reagents used exclusively for the resolution of racemates are not included, as these are treated in more detail in Section A.2. Enzymes, which can also be considered as chiral catalysts, are also not discussed they are beyond the scope of this section, which concentrates on chemical techniques. 

Organic functionalities can also be inserted into aminochlorooligosilanes by salt elimination with lithium or Grignard reagents. This type of reaction yields various specifically organic-substituted aminosilanes which are able to react with HCI and to form the corresponding chlorosilanes (Scheme 4). Via this reaction type different olefinic functionalized disilanes were prepared [9],... 

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