Structure target

If both starting structure and target structure are known, the method of targeted molecular dynamics simulation can be used to enforce a conformational transition towards the given final structure during a given simulation time ([Schlitter et al. 1994]). 

Following the similar structure - similar property principle", high-ranked structures in a similarity search are likely to have similar physicochemical and biological properties to those of the target structure. Accordingly, similarity searches play a pivotal role in database searches related to drug design. Some frequently used distance and similarity measures are illustrated in Section 8.2.1. 

Current research in LHASA is focused on developing new methods assisting users in choosing the most appropriate strategy for their target structures. Furthermore, the development of criteria for the evaluation of synthesis routes and/or algorithms for selecting optimal synthesis routes within the tree are discussed [34]. 

The retrosynthetic analysis of a target compound is a systematic approach in developing a synthesis plan starting with the target structure and working backward to available starting materials. 

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... 

The antibiotic rifamycin provides an example of a different and more common situation in which a target structure which has no overall symmetry has imbedded within it a Ci-symmetrical or nearly symmetrical substructure that, in turn, can be converted retrosynthetically to either a C2-symmetrical precursor or a pair of precursors available from a common intermediate. 6... 

Algorithms for machine-generated syntheses by application of connective transforms to target structures containing appendages, medium-sized rings, etc. have been described. ... 

Retron. The minimal substructural element in a target structure which keys the direct application of a transform to generate a synthetic precursor. 

Tactical Combination of Transforms. A standard combination of two or more transforms which can be used together to provide overall simplification of a target structure. 

The organization of Part Two is according to structural type. The first section, Chapter Seven, is concerned with the synthesis of macrocyclic compounds. Syntheses of a number of heterocyclic target structures appear in Chapter Eight. Sesquiterpenoids and polycyclic higher isoprenoids are dealt with in Chapters Nine and Ten, respectively. The remainder of Part Two describes syntheses of prostanoids (Chapter Eleven) and biologically active acyclic polyenes including leukotrienes and other eicosanoids (Chapter Twelve). 

There are a large number of naturally occurring molecules which have not yet been obtained by chemical synthesis. A convenient source of information on such compounds is The Dictionary of Organic Compounds, Fifth Addition (1982) and Supplements 1-5, published as a multivolume series by Chapman and Hall, New York and London J. Buckingham, Executive Editor. This compendium contains references to syntheses which are not included in this collection, especially those involving simpler target structures. 

Each section has the following structure synthesis of target structures, properties including spectral properties (meaning anomalous or confirming structure), reactions on ring atoms, reactions on substituents, partially saturated heterocycles, applications, and biological properties. 

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