Functional group targets groups

Mixed-mode sorbents contain both nonpolar and strong ion (cation and/or anion) exchange functional groups, targeted for the extraction of basic drugs. 

The basic chemical information used for functional groups, protective groups, sensitivities and reaction conditions is represented by binary sets, and manipulated with logical set operations, AND, OR, XOR, and SUBSET. A binary set containing the current functional groups is established during perception of the target ... 

Due to the large number of amphiphilic copolymers claimed for potential applications as drug release micelles, we shall consider at first the A-B and A-B-A structures, where some of them are specifically functionalized with targeting groups, followed by the more recently developed copolymer structures, for example star, graft A-B-C and polymer complexes. 

Recently, organic moiety-functionalized mesoporous materials could be introduced onto the internal pore surfaces through the direct design of organic functional groups targeted for a variety of applications such as catalysis, sensing, and separation. 

Descriptors have to be found representing the structural features which are related to the target property. This is the most important step in QSPR, and the development of powerful descriptors is of central interest in this field. Descriptors can range from simple atom- or functional group counts to quantum chemical descriptors. They can be derived on the basis of the connectivity (topological or... 

Tran orm-based or long-range strategies The retrosynthetic analysis is directed toward the application of powerful synthesis transforms. Functional groups are introduced into the target compound in order to establish the retion of a certain goal transform (e.g., the transform for the Diels-Alder reaction, Robinson annulation, Birch reduction, halolactonization, etc.). 

Analysis The one functional group is something of a red herring since we shall put in the acetyl side chain by a Friedel-Crafts reaction on the real target molecule, 399A ... 

If the target molecule is polyfunctional the synthons must contain more than one functional group. 

In later sections of this chapter we shall concentrate on the stereochemistry of target molecules, although the functional group chemistry will, of course, remain the basis of all synthetic operations. In this section we shall analyze synthetic functional group chemistry in two ways ... 

The systematic application of both antithetic steps will now be exemplified with the admittedly trivial synthesis of 3-methylbutanal (isovaleraldehyde). Functional group operations would yield the following alternative target molecules ... 

Since (A) does not contain any other functional group in addition to the formyl group, one may predict that suitable reaction conditions could be found for all conversions into (A). Many other alternative target molecules can, of course, be formulated. The reduction of (H), for example, may require introduction of a protecting group, e.g. acetal formation. The industrial synthesis of (A) is based upon the oxidation of (E) since 3-methylbutanol (isoamyl alcohol) is a cheap distillation product from alcoholic fermentation ( fusel oils ). The second step of our simple antithetic analysis — systematic disconnection — will now be exemplified with all target molecules of the scheme above. For the sake of brevity we shall omit the syn-thons and indicate only the reagents and reaction conditions. 

Affinity Labels. Active site-directed, irreversible inhibitors or affinity labels are usually substrate analogues that contain a reactive electrophilic functional group. In the first step, they bind to the active site of the target enzyme in a reversible fashion. Subsequentiy, an active site nucleophile in close proximity reacts with the electrophilic group on the substrate to form a covalent bond between the enzyme and the inhibitor, typically via S 2 alkylation or acylation. Affinity labels do not require activation by the catalysis of the enzyme, as in the case of a mechanism-based inhibitor. 

Additional keying information can come from certain other structural features which are present in a retron- or partial-retron-containing substructure. These ancillary keying elements can consist of functional groups, stereocenters, rings or appendages. Consider target structure 5... 

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