Structures Systems Generic

ROSDAL is used in the Beilstein-DIALOG system [17] as a data exchange format. The code can represent not only full structures and substructures but also some generic structures. 

In the previous chapter we have defined the generic rank as a property of structural matrices. Let us now introduce some new concepts in connection with structural systems and their associated graphs. 

Fig. 8 Generic structure of the frzs(imino)pyridyl iron(II) catalyst system studied in [41, 42]...

Another searching capability is required by the need to find a partial structure or substructure in a database that includes generic structures. The ability to do a substructure search is standard in modem chemical structure information systems. The problem is more complicated when generic structures must be searched, yet even more necessary since the generic might represent millions of specific structures. The query in Fig. 8 is compared with the generic structure to find the set of specific structures. 

Were this not the case, either a phytotoxic effect would result (as for 2,4-D) or an ineffective fungicide would result. Exactly these effects are achieved when through synthesis the solubility of the sulfenimides is increased. This author has, alas, quite frequently converted good fungicides into mediocre herbicides by such synthetic effort on the solubility modifications of the sulfenimide generic structure. A systemic must then be preferably a chemically relatively stable substance and not a highly reactive nucleophile or electrophile. 

Figure 5.2 Structural framework of the generic development system...

Interpretation of generic, or Markush, structures is a very useful but nontrivial task, and from the published work, it appears that so far, CLiDE is the only system among the various structure recognition systems introduced in Projects, above, that addresses the problem of generic structure interpretation. 

The first examples of urea-containing dimeric capsules were discovered independently by Rebek and Bohmer [165,166]. These are based on calix[4]arene ethers, in which the lower rim ether units help to fix the calixarenes in a cone conformation via intramolecular interactions. Figure 60 shows the generic structure of such systems. Synthetically, the urea calixarenes are readily prepared. The calixarenes are first nitrated, followed by a reduction of these groups into amines. The urea derivatives are fixed to the upper rim by reaction of the p-amino calixarenes with isocyanates. Many systems were studied using differently substituted ureas which contain either short alkyl chains or simple phenyl derivatives. Studies also involved the changing of the lower rim ether substituents. 

This is definitely an incomplete list of potentially interesting search queries but shows that even a generic documentation system like an ELN requires at least interfacing capabilities to provide this search functionality to a scientist. Any of these searches may be combined with either chemical or nonchemical searches. Spectra, chromatograms, structures, and reactions appear in the hit list for a combined search, the result shown in the hit list might be a combination of text with one of these data types. 

Not all the members of this group are, technically, quinolones, because naphthyridine, pyridopyrimidine, and cinnoline derivatives (Fig. 7-1), which each contain additional nitrogen atoms in one or the other of the two fused rings, are also represented. It may be useful to consider them all quinoline-type compounds. Thus one may view naphthyridine drugs as 8-aza-4-quinolones, the pyridopyrimidine ring compounds as 6,8-diaza-4-quinolones and the cinnoline system as a 2-aza-4-quinolone. The following compromise generic structure may depict the common denominator to all the active compounds. 

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