摘要:

AbstractCorrelation of molar refraction with the first order molecular connectivity index was found to be excellent for alkylgermanes of molecular formula GeCnH2n+4. The correlation was further improved by the use of either of two empirically‐modified first order molecular connectivity indices, which reflect either the larger covalent radius of germanium compared to carbon or the longer germanium‐carbon bond length compared to the carbon‐carbon bond length. Use of the empirically‐modified indices improves the prediction of molar refraction for a mixed set of alkanes and alkylgermanes and for a mixed set of alkanes, alkylsilanes, and alkylg

ISSN:0931-8771    

DOI:10.1002/qsar.19880070202

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractThe MNDO semiempirical SCF‐MO method has been used to calculate charge distributions of a series of histamine H2‐receptor antagonists. The investigated compounds concern mifentidine (N‐isopropyl‐N′‐(4‐1H‐imidazol‐4‐yl‐phenyl)formamidine) analogues, in which the imidazole moiety has been substituted or replaced by various aromatic heterocyclic groups. A correlation has been found between H2‐antagonistic activity as determined by inhibition of specific [3H]‐tiotidine binding to the H2receptors of a guinea pig cortex preparation, and the net atomic charges of two of the atoms (X‐H bond in which X is a nitrogen or carbon atom) in the heterocycle. The binding capacity of the ligand molecule to the receptor is enhanced when the electronic population of atom X and the positive charge on the proton are higher. Assuming that the difference between both charges might effectively serve as a valuable substitute for the hydrogen bond forming capacity of the X‐H group, the conclusion can be drawn that this property of the heterocycle plays an important role in the interaction process of the ligand with its H2‐receptor. The obtained regression equation(s) suggest that the monocation (formamidine moiety protonated) is the species rela

ISSN:0931-8771    

DOI:10.1002/qsar.19880070203

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractNarcotic effects of organic nonelectrolytes to the tadpole (logC), minimum blocking concentrations for stoppage of electrical activity in the muscle of the frog, Rana pipiens (logMBC), and binding of nonelectrolytes to bovine serum albumin (log1/C) are well correlated by the following equations,where VIis the intrinsic (van der Waals) molar volume, and π*, βmand αmare the solvatochromic parameters that scale solute dipolarity/polarizability, hydrogen bond acceptor basicity, and hydrogen bond donor acidity.That increasing solute π*leads to lesser partition into the biosystem compared with its aqueous environment, but also leads to greater toxicity or anesthetic effect is suggested to implicate in the mechanism of toxicity or narcosis a specific association effect between the more dipolar solutes (toxicants) and a molecule involved in the transmission of nervous impul

ISSN:0931-8771    

DOI:10.1002/qsar.19880070204

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractA series of twenty‐six insecticidal pyrethroid ethers were subjected to multiple regression QSAR analysis. The results indicated that candidate insecticides should have a lipophilicity, as expressed in the log of the calculated octanol/water partition coefficient, of approximately 5.5. There was a general, negative correlation of activity with molar refractivity, suggesting that molecular size, or volume, and polarizability should not be too large for optimum insecticidal activity.The substituents on the aromatic ring adjacent to the cyclopropyl moiety appear to exert their primary influenceviaelectronic effects. For optimum activity strongly electron donatingparasubstituents are required. Electron‐withdrawing or donating effects, size and lipophilicity of the substituents on the cyclopropyl ring appear to influence the insecticidal activity. Substituents which are small, not very polarizable, not very lipid soluble and which have a positive polar electronic substituent constant are likely to be the most effective. This is consistent with the hypothesis of the pyrethroids and other toxins acting at specific receptors adjacent to ion channels embedded in nerve membranes, causing partial blockade of these sodium, or other ion, channels.There were very few changes made to the substituents on the other aromatic ring. The results indicated that electron withdrawing groups were favoured as substituents on that r

ISSN:0931-8771    

DOI:10.1002/qsar.19880070205

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractA QSAR model has been developed for the quantitative prediction of mutagenic activity in a class of unsaturated dialdehydes. The conformers of each dialdehyde were obtained from molecular mechanics (MM) calculations. The MM results were used to extract descriptors to represent the three‐dimensional structure of each compound. Thirty‐one theoretical descriptors (e.g.from MM and CNDO calculations) were correlated with the mutagenic activities of six unsaturated dialdehydes in three strains in the Ames Salmonella assay. The method of partial least squares in latent variables, PLS, was chosen for the multivariate statistical analysis. The activity of a seventh dialdehyde was predicted from this model, in encouragingly good agreement with experiment. The set of compounds is admittedly a small one, but as an initial investigation the results show the potential of this approach to QSAR model

ISSN:0931-8771    

DOI:10.1002/qsar.19880070206

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

ISSN:0931-8771    

DOI:10.1002/qsar.19880070207

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

ISSN:0931-8771    

DOI:10.1002/qsar.19880070208

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

ISSN:0931-8771    

DOI:10.1002/qsar.19880070201

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY