Organic QSAR study

The increased interest in 3D aspects of organic chemistry and quantitative structure-activity relationship (QSAR) studies has caused an increasing need for a much broader access to 3D molecular structures from experiment or calculation. 

Lewis, D. F., Ioannides, C., and Parke, D. V. (2003) A quantitative structure-activity relationship (QSAR) study of mutagenicity in several series of organic... 

In this context, interesting exhaustive QSAR studies dealing with the assessment of phototoxic hazards of PAHs to aquatic organisms such as Daphnia were published some years ago [12-14]. Authors chose a descriptor based on the energy difference between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO). They proposed that aromatic chemicals with a HOMO-LUMO gap energy in a window of 7.2 eV 0.4 eV have a high phototoxic potential. 

Lipnick, R.L., Watson, K.R. and Strausz, A.K. (1987) A QSAR study of the acute toxicity of some industrial organic chemicals to goldfish. Narcosis, electrophile and proelectrophile mechanisms. Xenobiotica, 17,... 

Nendza (1998) has defined bioaccumulation as uptake by an organism of a chemical from the environment via any possible pathway, and this can be subdivided into biomagnification (uptake via the food chain) and bioconcentration (uptake from the surrounding milieu). As we shall see, it is the latter that has been the subject of by far the greater number of quantitative structure-activity relationship (QSAR) studies of bioaccumulation. The bioconcentration factor (BCF) is defined as ... 

Derived from physical organic chemistry and the - Hammett equation, this can be considered to be the first approach to modern QSAR studies. Proposed by Hansch and co-workers in the early 1960s [Hansch et al, 1962 Hansch et al, 1963 Hansch and Fujita, 1964 Hansch et al, 1965 Hansch and Anderson, 1967 Hansch, 1969 Hansch, 1971 Hansch, 1978], it is the investigation of the quantitative relationships between... 

Gramatica, P., Consonni, V. and Todeschini, R. (1999a). QSAR Study on the Tropospheric Degradation of Organic Compounds. Chemosphere, 38,1371-1378. 

Palyulin, V.A., Radchenko, E.V. and Zefirov, N.S. (2000). Molecular Field Topology Analysis Method in QSAR Studies of Organic Compounds. J.Chem.Inf.Comput.Sci., 40, 659-667. 

Several series of novel chirality descriptors of chemical organic molecules were introduced by Golbraikh et al. [5, 6]. These descriptors have been implemented in a QSAR study with a high content of chiral and enantiomeric compounds. It was shown fhat for all data sets 2D-QSAR models that use a combination of chirahty descriptors wifh conventional topological descriptors afford better or similar predictive abihty when compared to models generated wifh 3D-QSAR approaches. 2D-QSAR mefhods enhanced by chirahty descriptors present a powerful alternative to popular 3D-QSAR approaches. 

QSAR studies date back to the nineteenth century. In 1863, A. F. A. Cros at the University of Strasbourg observed that toxicity of alcohols to mammals increased as the water solubility of the alcohols decreased. In the 1890s, Hans Horst Meyer of the University of Marburg and Charles Ernest Overton of the University of Zurich, working independently, noted that the toxicity of organic compounds depended on their lipophilicity. 

Khadikar, P.V., Phadnis, A. and Shrivastava, A. (2002) QSAR study on toxicity to aqueous organisms using the PI index. Biootg. Med. Chem., 10, 1181—1188. 

Marrero-Ponce, Y, Castillo-Garit, J.A., Torrens, F., Zaldivar, V.R. and Castro, E.A. (2004b) Atom, atom-type, and total linear indices of the molecular pseudograph s atom adjacency matrix application to QSPR/QSAR studies of organic compounds. Molecules, 9, 1100-1123. 

Ohlenbusch, G. and Frimmel, F.H. (2001) Investigations on the sorption of phenols to dissolved organic matter by a QSAR study. Chemosphere, 45, 323-327. 

QSAR studies have become extremely useful towards understanding the toxic levels of bio-organisms. In this cmitext, various topological descriptors [158—160] are introduced to quantitatively correlate the hazardous effect of several chemical compounds on the ecosystem. The toxic effects of various compounds on fishes are reported in detail through fruitful SAR-based regression analyses [161—173]. 

Comparison of compounds from different classes reveals that they may act by the same mode in some organisms, but by dissimilar modes in others. Applying this rationale to QSAR studies implies that the occurrence of outliers cannot be uniform for all models, and that toxicity exceeding the... 

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