摘要:

AbstractThe method of comparative molecular field analysis (CoMFA) has been applied to a series of 6 reactions involving a transition‐metal center and a series of substituted phosphine ligands. A CoMFA analysis of parameters used in classical QSAR including the Tolman cone angle and Brown's steric parameter ERhas also been performed. Provided that the dataset of compounds is carefully chosen and is sufficiently large, CoMFA can be used in place of traditional QSAR methods which have employed Tolman cone angles and carbon‐13 chemical shifts as parameters. The CoMFA results show that steric and electronic factors have comparable weight in determining chemical reactivity in the types of reactions conside

ISSN:0931-8771    

DOI:10.1002/qsar.19960150102

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractSome simple molecular structural considerations relating to atom type were used as the independent variable inputs to an artificial neural network with the dependent variables consisting of the physicochemical parameters molecular refractivity and hydrophobicity. The low root mean squared error in each case was sufficiently low for the further mapping of biological activity to be attempted. A set of 236 dihydrofolate reductase inhibitors, for which the biological activity was known, was fitted in a similar manner and again producing a low root mean squared error. It is concluded that neural networks can be used to predict biological activity, within a series of closely related molecules, from molecular structural considerations alone so saving much effort in synthesis andin vivotesting with new candidate molecules.

ISSN:0931-8771    

DOI:10.1002/qsar.19960150103

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractQuantitative structure ‐ activity relationship (QSAR) studies have been performed on some non‐benzodiazepine series of benzodiazepine receptor (BZR) ligands, namely a series of thienylpyrazologuinolines and a series of imidazoquinoxalines. Studies reveal the merits and demerits of the substituents and their physicochemical properties in each case, in addition to the essential requirements for the binding for each type of lig

ISSN:0931-8771    

DOI:10.1002/qsar.19960150104

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractBy means of clustering according to structure similarity one can manage easily large databases containing several tens of thousands of chemicals. A new methodology in which statistical criteria are used to decide the optimal threshold in the clustering process is proposed. Clustering defined the several chemical classes that were present in our training set. All the clusters except one showed a correlation of logWS with logKowand melting point. The latter covers all chemicals with melting points below room temperature, resulting in a logWS‐logKowrelationship. This cluster showed also a weak correlation, probably due to the insufficient number of available screens. Such a limited number of screens permits that rather different chemicals share the same cluster. Using statistical criteria, our approach resulted in 3 QSARs with reasonably good predictive capabilities. The models resulting from the smaller clusters are characterised by high correlation coefficients, describing the cluster itself very well. Due to our stringent bootstrap criterion, they perform close to random models as indicated by the statistical characteristics. Some clusters showed rather low correlations. The well behaved models proved their usefulness through external validation. The logWS‐values calculated using our QSARs agreed within 1 log‐unit with these reported in the liter

ISSN:0931-8771    

DOI:10.1002/qsar.19960150105

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

ISSN:0931-8771    

DOI:10.1002/qsar.19960150106

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

ISSN:0931-8771    

DOI:10.1002/qsar.19960150107

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

ISSN:0931-8771    

DOI:10.1002/qsar.19960150108

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

ISSN:0931-8771    

DOI:10.1002/qsar.19960150101

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY