Chain and functionalization

Bacterial siderophores are typically small peptidic molecules, which contain side chains and functional groups that can provide high-affinity ligands for coordination of ferric ions. The structures of some siderophores are shown in Drechsel and Jung [142]. Siderophore synthesis occurs via enzymatic assembly by nonribosomal peptide synthetases [144], In bacteria, siderophore synthesis is... 

Telechelic polymers rank among the oldest designed precursors. The position of reactive groups at the ends of a sequence of repeating units makes it possible to incorporate various chemical structures into the network (polyether, polyester, polyamide, aliphatic, cycloaliphatic or aromatic hydrocarbon, etc.). The cross-linking density can be controlled by the length of precursor chain and functionality of the crosslinker, by molar ratio of functional groups, or by addition of a monofunctional component. Formation of elastically inactive loops is usually weak. Typical polyurethane systems composed of a macromolecular triol and a diisocyanate are statistically simple and when different theories listed above are... 

C. PREPARATION OF THE KEY INTERMEDIATE ELABORATION OF THE HYDROXYLETHYLIDENE SIDE CHAIN AND FUNCTIONALIZATION OF THE E-RING... 

Here, again, we start from compressible SCFT formalism described in Section 2.2 and consider a model system in which bulk polymer consists of "free" matrix chains (Ny= 300) and "active" one-sticker chains (Na= 100). Flory-Huggins interaction parameters between various species are summarized in Table 1. This corresponds to the scenario in which surfactants, matrix chains, and functionalized chains are all hydrocarbon molecules (e.g., surfactant is a C12 linear chain, matrix is a 100,000 Da molecular weight polyethylene, and functionalized chain is a shorter polyethylene molecule with one grafted maleic group). The nonzero interaction parameter between voids and hydrocarbon monomers reflects the nonzero surface tension of polyethylene. The interaction parameter between the clay surface and the hydrocarbon monomers, Xac= 10 (a = G, F, A), reflects a very strong incompatibility between the nonpolar polymers and... 

Primary antioxidants terminate free radical chains and function as electron donors. They include the phenolic antioxidants, butylated hydroxyanisole (BHA), butylated hydroxy-toluene (BHT), tertiary butyl hydroquinone (TBHQ), alkylgalates, usually propylgallate (PG), and natural and synthetic tocopherols and tocotrienols. 

Model compounds nthesized from Ohamino acids contain asymmetric carbcm atcrnis in the main chain and functional groups in the substituent. This situaticm resembles that encountered in enzymes. 

As implied by the above description, cytochrome oxidase is the terminal member of the so-called respiratory chain and functionally located at the confluence of the electron current... 

Explain why carbon s atomic properties lead to formation of four strong bonds, multiple bonds, chains, and functional groups ( 15.1) (EPs 15.1-15.4)... 

Another relevant library-building concept that also emerged from the diversity of natural products assumes that such molecular scaffolds primarily hold the biological activity, and the side chains and functional groups only modify or fine-tune the interaction. Therefore, a new term was introduced by the Schreiber group, skeletal diversity (Kwon, Park, and Schreiber, 2002). Instead of increasing the overall structural diversity or dissimilarity, skeletal diversity is required in libraries involved in chemical genetics which can only be achieved by diversity-oriented synthesis (DOS) (Arya et al., 2005 Tan, 2005). 

Molecular orientation of the hydrocarbon chain and functional groups in a LB film can be investigated by compari-... 

Each classification of amino acids is somewhat imprecise and conforms to certain purposes. The most common way of sorting the proteinogenic amino acids in food chemistry is classification according to the structure of their side chain and functional groups present therein. This wiU distinguish the following groups of amino acids ... 

Time plays an important role in the drag discoveiy process. Different synthetic strategies have to be used to obtain a diverse set of molecules. This is needed to explore the property space and to obtain appropriate answers (properties) during the optimisation cycle. This desire often leads to the concept of introducing important side chains and functionalities in the last... 

Most of the foregoing deals with chemical substances composed of ordinary atoms arranged into rings, chains, and functional groups in two dimensions. There are several other variations in chemical substances that are reflected in nomenclature and that can either help or hinder searching. These are stereochemical descriptions and isotopic substitutions. 

In spite of the diverse classes of steroid compounds, at the present time they are all connected with one another by partial syntheses which enable us to pass from one class to another by complicating or simplifying the structure through the introduction, elimination, or transformation of side chains and functional substituents. The establishment of synthetic links between all the classes of steroids enables us to classify as total synthesis, properly so-called, only the construction of the cyclopentano-... 

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