Computer search

The construction of loops relevant to this system was described in Section IVD. In this section, the computational search for the conical intersection using the... 

Pranata J and W L Jorgensen 1991. Computational Studies on FK506 Computational Search and Molecular Dynamics Simulations in Water. Journal of the American Chemical Society 113 9483-9493. 

Documentation abstracts, useful as they are, may also prove inadequate for final decisions, which would make it necessary for the searcher to obtain and examine copies of full patent specifications. Although the increasing availabihty of sets of full specifications on CD-ROM at modest cost is making it easier for searchers to have in their collections copies of those specifications they might need to consult, the necessity to go beyond computer output, whether to abstracts or full specifications, is stiU one of the bottlenecks of computer searching, and therefore an area in which significant new developments are hoped for. 

Traditional paging through patent office gazettes and printed abstract bulletins stiU serves a usefiil purpose in patent alerting. It can be difficult to frame a query for a computer search on all the subject matter that might be of interest to an organization. The human mind can spot unanticipated material and relate it to interests, something presendy beyond the power of the computer. 

Sea.rch-Ma.tch. The computer identifies which crystalline phases (components) match the unknown pattern by using a file of known powder patterns maintained by the International Center for Diffraction Data (ICDD). The Powder Diffraction File contains interplanar t5 -spacings d = A/(2sin0)] and intensities of the diffraction maxima for each crystalline powder pattern submitted to the ICDD. Currendy there are about 65,000 patterns in the file. Current search—match programs can successfully identify up to seven components in an unknown pattern. A typical diffraction pattern of an unknown sample and the components identified by the computer search-match program is shown in Figure 15. 

A computer search of volumes 70-95 of Chemical Abstracts using the keyword Pyrazine resulted in more than 2600 references, and, after removal of fused pyrazine systems and cross-referencing the remaining references, this number increased to approximately 7000 in total. When the benzopyrazines quinoxaline and phenazine were added the number of references was in excess of 10 000, all of which might be considered to be relevant to a chapter devoted to pyrazines and their benzo analogues. 

Both common and systematic names of compounds are used throughout this volume, depending on which the Editor-in-Chief felt was more appropriate The Chemical Abstracts indexing name for each title compound, if it differs from the title name, is given as a subtitle Systematic Chemical Abstracts nomenclature, used in both the 9th and 10th Collective Indexes for the title compound and a selection of other compounds mentioned in the procedure, is provided in an appendix at the end of each preparation. Registry numbers, which are useful in computer searching and identification, are also provided in these appendixes. Whenever two names are concurrently in use and one name is the correct Chemical Abstracts name, that name is adopted. For example, both diethyl ether and ethyl ether are normally used. Since ethyl ether is the established Chemical Abstracts name for the 8lh Collective Index, it has been used in this volume The 9th Collective Index name is 1,1 -oxybisethane, which the Editors consider too cumbersome. 

Dayhoff MO. Computer search for active-site configurations. J Am Chem Soc 1964 86 2295-7. 

One early step in the workflow of the medicinal chemist is to computationally search for similar compounds to known actives that are either available in internal inventory or commercially available somewhere in the world, that is, to perform similarity and substructure searches on the worldwide databases of available compounds. It is in the interest of all drug discovery programs to develop a formal process to search for such compounds and place them into the bioassays for both lead generation and analog-based lead optimization. To this end, various similarity search algorithms (both 2D and 3D) should be implemented and delivered directly to the medicinal chemist. These algorithms often prove complementary to each other in terms of the chemical diversity of the resulted compounds [8]. 

Unfortunately, the number of systems in which it can be established whether Keller s model is realistic for a particular case is severely limited since the original polymer is usually not soluble in the same medium as the ultimate reaction product. In cases where the entire course of the reaction can be followed, as in the basic hydrolysis of polyacrylamide, investigators have analyzed their results by a computer search for the k, k, k values which fit best their kinetic data (9). This, or course, does not answer the question whether the model using these three rate constants provides a full description of a particular case. 

Sulfone-based y-secretase inhibitors including cyclohexane 45 (Ap IC50 = 3nM) have been reported [105]. Variations on this series include 3- and 4-substituted analogs such as 46 and 30, and highly potent bicyclic systems such as 47 (Ap IC50 = 0.06 nM), which was found to lower brain Ap in mice with an ED50 of 3.9mg/kg [106-108]. Piperidine sulfone 48 resulted from modification of hits from a pharmacophore-based computational search [109]. 

The best-known and the most commonly used hyphenated method is GC-MS more specifically, and most commonly, capillary column GC combined with quadrupole MS. This type of instrumentation is controlled by computer and data collected and analyzed by dedicated computer programs. The mass spectra produced by the analytes can be compared to those in a library of mass spectra of known compounds using a computer search algorithm. The computer program finds known compounds that best match the spectra of the analytes of interest. 

The literature has been covered as far as it was available to the author until the fall of 1983. In the course of the literature search certain difficulties had to be overcome. Many publications contain valuable 13C NMR information without mentioning so explicitly in the title or abstract thus, the information cannot easily be retrieved, even through Chemical Abstracts. Various reviews as well as computer search systems have been utilized as sources. Moreover, due to the enormous wealth of I3C NMR spectral data that has appeared in the last decade it is impossible to include all information available. Omission of certain papers, however, does not at all imply judgment as to their scientific value. In the beginning of this chapter (Sect. II) a brief account is presented of the basic... 

Theoretical calculations can also provide physicochemical data, which can be used as an input for 3D-QSAR correlation studies [134,141]. There is a current trend in the area of lead-finding in the pharmaceutical industry to use calculations to set up computer search profiles to be used in the screening of large structural databases, such as the chemical suppliers databases and the internal company databases. 

Gund, P., Wipke, W.T., Iangridge, R. Computer searching of a molecular structure file for pharmacophoric patterns. Comput. Chem. Res. Educ. Technol. 1974, 3, 5-21. 

Bnilding on the fonndation of these stndies, Haddad et al. used rings I and II of paromomycin (called paromomine) as the minimum structural motif in a computational search of over 273,000 componnds that might bind an A-site template. Results of this search were then narrowed based on steric and energetic demands. Several componnds were snbseqnently synthesized and shown to bind to an RNA model of the A-site, with some of the compounds (e.g., 2) exhibiting broad-spectrum activity in bacteria. X-ray strnctnres with the RNA models and with the 30S ribosome vindicated the design principles. The compounds do bind to the A-site and they do flip the two bases mentioned previously to the extrahelical position, as do other antibiotics of this class. 

Keywords The repetition of key terms and concepts in the abstract and title is commonplace. Because both the title and abstract are often used for computer searches, it is important that key terms be included... 

Relationship between a title, an abstract, and a computer search... 

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