Study on the Quantitative Structure-toxicity Relationships for the Selected Esters by Using Molecular Electronegativity Interaction Vector (MEIV)

The molecular electronegativity interaction vector （MEIV） was used to describe the molecular structure of 30 selected esters. Two excellent QSTR models were built up by using multiple linear regression （MLR） and partial least-squares regression （PLS）. The correlation coefficients （R） of the two models were 0.945 and 0.941, respectively. The models were evaluated by performing the cross validation with the leave-one-out （LOO） procedure. The cross-verification correlation coefficients （RCV） of the two models were 0.921 and 0.919, respectively. The results showed that the models constructed in this work could provide estimation stability and favorable predictive ability.

Structural Characterization and Retention Time Simulation of Allergenic Fragrances

By classifying non-hydrogen atoms of organic compounds,parametric dyeing,and establishing the relationship between non-hydrogen atoms,new structure descriptors were obtained.The structures of 48 common allergenic fragrance organic compounds were parametrically characterized.The multiple linear regression(MLR)and partial least-squares regression(PLS)methods were used to build two models of relationship between the compound structure and chromatographic retention time.The stability of the models was evaluated by the"leave-one-out"cross test,and the predictive ability of the models was tested using an external sample set.The correlation coefficients(R2)of the two models are 0.9791 and 0.9744,those(R(CV)~2)of the cross test are 0.8542 and 0.7464,and those(R(test)~2)of the external prediction are 0.9802 and 0.9367,indicating that the models built have good fitting ability,stability and external forecasting capabilities.The structural factors affecting the chromatographic retention time of the compounds were analyzed.The results show that the compound with more secondary carbon atoms may have larger chromatographic retention time(tR)value.This paper has certain reference value for the study on the relationship between the structures and properties of allergenic fragrance organic compounds.

Structural Characterization and Aquatic Toxicity Prediction of Esters

Based on the three-dimensional structures of the compounds,the structures of 48 ester compounds were expressed parametrically.Through multiple linear regression and partial least-squares regression,the relationship models between ester compound structures and aquatic toxicity log(1/IGC50)were established.The correlation coefficients(R2)of the models were 0.9974 and 0.9940,and the standard deviations(SD)were 0.0469 and 0.0646,respectively.The stability of the models was evaluated by the leave-one-out internal cross-test.The correlation coefficients(RCV2)of the models of interactive tests were 0.9939 and 0.8952,and the standard deviation(SDCV)was 0.0715 and 0.0925,respectively.The external samples were used to test the predictive ability of the models,and the correlation coefficients(Rtest2)of the external predictions were 0.9955 and 0.9955,and the standard deviations(SDtest)were 0.0720 and 0.0716,respectively.The molecular structure descriptors could successfully represent the structural characteristics of the compounds,and the built models had good fitting effects,strong stability and high prediction accuracy.The present study has a good reference value for the study of the structure-toxicity relationship of toxic compounds in the environment.