Starting compounds, catalog

Starting materials catalog 6000 compounds Figure 10. Examples of Operator Selection Choices... 

SUCCEEDED, whether by its RNODE or the SNODE tasks or even by its designating a molecule which is available in the Catalog of Starting Compounds. 

To seat ch for available starting materials, similarity searches, substructure searches, and some classical retrieval methods such as full structure searches, name searches, empirical formula searches, etc., have been integrated into the system. All searches can be applied to a number of catalogs of available fine chemicals (c.g, Fluka 154]. In addition, compound libraries such as in-housc catalogs can easily be integrated. 

Figure 10.3-16. The principle of similarity searches. The query (target, precursor) as well as the catalog compound are transformed by the criterion maximum oxidation state". Since the transformation for both compounds results in the samie transformed structure, the catalog compound is presented to the user as a suitable starting material. The comparison of the structure is performed by a hashcode algorithm.

Numerous ethical drug companies also had saw palmetto-based formulas for similar problems. The Tilden Company, which had started producing herbal medicines in New Lebanon, New York, in 1824, listed three saw palmetto formulas in its 1937 catalog, including a saw palmetto compound that contained Serenoa, sandalwood, kola nut, and celery seed. 

The active development, support, and distribution of WODCA was stopped in 2005. The distributor. Molecular Networks — a spin-off of Gasteiger s research team — is currently developing a Web-based expert system called Retrosynthesis Browser (RSB) for retrosynthetic analysis of a given target compound. RSB scans reaction databases to suggest new synthetic routes and simultaneously searches in catalogs of available starting materials for the proposed precursors. 

Then nucleophilic half-reactions for each side are paired only with electrophilic ones on the other to define full isohypsic constructions and the substrates for these (as zp-lists). These substrate zp-lists now become the products for repeating the operation with the next bond defined in the bondset order. When all the bondset bonds have been sequentially treated in this way, there will result the zp-lists of the four generated starting materials and these can now be looked up in the catalog. If all four are found to be available compounds a successful synthetic sequence has been found and is recorded. 

The output from SYNGEN may be examined graphically in a number of ways which also allow for deletion by the user of unwanted reactions, intermediates, starting materials, or even overall bondsets. Also, a matrix of the number of routes by cost and number of steps may be accessed to focus examination on only a subset of them. Whole routes are presented, each complete on a whole screen with a description of the reaction types, the catalog starting materials, and the overall cost and steps. These may be examined one at a time in an order of preference based on cost or other criteria. When any whole route is displayed, unwanted compounds or reactions in it may be deleted directly on screen, so that they will not appear again in any routes displayed later. 

When transformations can be coded and applied stereo-specifically, catalog lookups for starting materials must also distinguish between stereoisomers. Sometimes this condition is relaxed, because it may be argued that if one stereoisomer is available then a different one should be obtainable by a slight modification of the synthesis of the catalog compound. 

---