Families compounds

Markush structures rcprcHL-uts compound families - widespread in patents nianual in/ontput convertible into otlicr representations high number of compounds less compact code ambiguous difficult to extract individual compounds... 

Patent databases are therefore integrated databases because facts, text, tables, graphics, and structures are combined. In patents that include chemical aspects (mostly synthesis or processing), the chemical compounds are often represented by Markush structures (see Chapter 2, Section 2.7.1). These generic structures cover many compound families in a very compact maimer. A Markush structure has a core structure diagram with specific atoms and with variable parts (R-groups), which are defined in a text caption. The retrieval of chemical compounds from Markush structures is a complicated task that is not yet solved completely satisfactorily. 

Equation (2-2), another somewhat simpler method for estimating the critical temperature of pure hydrocarbons only, is the method of Nokay " and requires the normal boiling point, the relative density, and the compound family. 

Owing to the complexity and dynamic character of real environmental scenarios, it is not always possible to predict concentrations with desirable level of precision. Nevertheless, even though experimental measurements are not replaceable by PECs, this approach can still serve as a useful tool for supporting hazard assessment programs. Making predictions also can help identifying compounds or compounds families that should be monitored, as well as what the most exposed compartments... 

In this equation a c stands for the sensivity of the observed carbon atom within a given parent compound family, and T),. is a reference shift. The R values are obtained by DARC/PELCO topological analysis (416). 

In clinical chemistry, interpretation of the data can be quite simple or complex. In the case of MS/MS applications pertaining to a single analyte, all that is needed is the intensity value from the mass of a peak of interest and its internal standard. Viewing of a spectrum is not necessary. For profile methods such as full-scan acylcarni-tines, amino acids, or other compound families, the interpretation is more complex. With multiple related components, calculation of the concentration of many key metabolites is required. The system generally has multiple internal standards, external standards, or both. In addition to the concentration calculations, examination of a profile is often best achieved by viewing the spectra together with the quantitative information. 

It is instructive to look at the refractive indices for a variety of chemical structures (Table 3.1.) What one quickly sees is that polar compounds are not the same as polarizable compounds. Indeed, polarizability is more related to chemical structure features like overall size (higher homologs within a compound family have greater polarizabilities), and presence of conjugated electron systems (benzene is more polarizable than hexane polarizability increases in the order benzene < naphthalene < pyrene). Finally, molecules with large atoms containing nonbonded electrons far from the nucleus (e.g., bromine, iodine) are generally more polarizable. After this brief diversion, now we continue to use refractive indices to estimate polarizabilities. 

Table 16.5 Proportions of the different compound families in males and females of Smeringerus mesaensis.

Compound Family Species Molecular formula Reference(s)... 

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