Octanol/water partition coefficient log

Two approaches to quantify/fQ, i.e., to establish a quantitative relationship between the structural features of a compoimd and its properties, are described in this section quantitative structure-property relationships (QSPR) and linear free energy relationships (LFER) cf. Section 3.4.2.2). The LFER approach is important for historical reasons because it contributed the first attempt to predict the property of a compound from an analysis of its structure. LFERs can be established only for congeneric series of compounds, i.e., sets of compounds that share the same skeleton and only have variations in the substituents attached to this skeleton. As examples of a QSPR approach, currently available methods for the prediction of the octanol/water partition coefficient, log P, and of aqueous solubility, log S, of organic compoimds are described in Section 10.1.4 and Section 10.15, respectively. 

Almost all widely used, reliable prediction models for logarithmic partition coefficients, and especially for the octanol-water partition coefficient log P w, are linear regression models with respect to fragment counts, atom types, bond types or... 

Breindl, A., Beck, B., Qark, T., Glen, R. C. Prediction of the n-octanol/water partition coefficient, log P, using a combination of semiempirical MO-calculations and a neural network. J. Mol. Model. 1997, 3, 142-155. 

Water 70pgL acetone 560gL ethanollSgL toluene400g L n-hexane 14g L n-octanol6.8g Yellow to orange odorless crystalline solid density 1.54gem at 20°C octanol/water partition coefficient (log P)5.45 at 25 °C... 

Readily soluble in organic solvents ethanol 51, acetone 77,toluene 63, n-octanol 13, n-hexane 0.53 g per 100 mL Colorless to white solidified melt, no dissociation constant in an accessible pH range, octanol/water partition coefficient (log /Cow) 4.07 at 25 °C. 

The log octanol-water partition coefficient (log Pq/w) probably is the most frequently used physicochemical parameter in medicinal chemistry [101 104]. Octanol, with a polar head and a flexible, nonpolar tail, has hydrogen-bonding capabilities and amphilicity similar to... 

The procedure takes as input parameters the measured (or calculated) pKa and the measured (or calculated) octanol-water partition coefficient, log P. The latter parameter is used to estimate the intrinsic solubility So, using the Hansch-type expression [38], log So = 1.17 — 1.38 log P, or an improved version for ionizable molecules of moderate lipophilicity (Fig. 6.6) ... 

Poole, S. K., Durham, D., Kibbey, C., Rapid method for estimating the octanol-water partition coefficient (log P-ow) by microemulsion electrokinetic chromatography,... 

The relationship between the herbicidal activity of 1,2,5-oxadiazole iV-oxides and some physicochemical properties potentially related to this bioactivity, such as polarity, molecular volume, proton acceptor ability, lipophilicity, and reduction potential, were studied. The semi-empirical MO method AMI was used to calculate theoretical descriptors such as dipolar moment, molecular volume, Mulliken s charge, and the octanol/water partition coefficients (log Po/w) <2005MOL1197>. 

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