O-ethyl-O-aryl-N-isopropyl-phosphoramidothioates have relatively high herbicidal ac-tivity. The exact and comprehensive QSAN study is the key to finding new compoundswith high activity. Artificial neural networks (ANN...O-ethyl-O-aryl-N-isopropyl-phosphoramidothioates have relatively high herbicidal ac-tivity. The exact and comprehensive QSAN study is the key to finding new compoundswith high activity. Artificial neural networks (ANNs) are a newly emerging field ofinformation processing technology. As ANNs can be taught complex nonlinearinput-output transformations and have the ability of adaptive learning, resistance tonoise and fault tolerance, they can solve the pattern recognition and funtionalmapping problems.展开更多
O-Aryl O-ethyl N-isopropyl phosphoramidothioates (Ⅰ) have herbicidal activity. In order to study the relationship between structures and activities of these compounds, more than thirty compounds (Ⅰ) have been prepar...O-Aryl O-ethyl N-isopropyl phosphoramidothioates (Ⅰ) have herbicidal activity. In order to study the relationship between structures and activities of these compounds, more than thirty compounds (Ⅰ) have been prepared by the reaction of O-aryl O-ethyl phosphorochloridothioates with isopropylamine in the presence of 40% NaOH at 0℃. The intermediates, phosphorochloridothioates, were prepared separately from a large excess of O-ethyl Phosphorodichloridothioate and various substituted phenols in the presence of 40% NaOH and a catalyrical amount of Et_3N at 0—5℃. As a result, higher purity and good yields were obtained.It was found that the activity of these compounds was highly dependent upon the substituents attached to the benzene ring with respect to the characteristic parameters π, E_s, σ and F by using Hansch's equation.It was indicated that hydrophobic (π), steric (E_s), and electronic (σ and F) effects of the substituents on the ring in those molecules seem to be of considerable importance in determining their biological activity.By replacing π with △R_m and a and F with △δ_p, respectively, in regression analysis a better correlation was obtained. Both △R_m and △δ_p were experimental data. The former was calculated from R_f measured with reversed-phase thin-layer chromatography and the latter was obtained from the difference between the chemical shifts of the ^(31)P NMR of compounds(Ⅰ) and that of the parent compound.展开更多
A computer-assisted retention prediction system (RPS) of fifteen O-ethyl O-aryl N-iso- propyl phosphoramidothioates (1) in reversed-phase HPLC was investigated. The system is based on the use of four physicochemical p...A computer-assisted retention prediction system (RPS) of fifteen O-ethyl O-aryl N-iso- propyl phosphoramidothioates (1) in reversed-phase HPLC was investigated. The system is based on the use of four physicochemical parameters (hydrophobicity , electric effect σ, field effect F and steric effect ) which is closely related to the retention mechanism in reversed-phase HPLC. The system was evaluated by comparing the measured retention data with the predicted ones. The predicted values were consistent with the measured values within a relative error of 11.5%.展开更多
文摘O-ethyl-O-aryl-N-isopropyl-phosphoramidothioates have relatively high herbicidal ac-tivity. The exact and comprehensive QSAN study is the key to finding new compoundswith high activity. Artificial neural networks (ANNs) are a newly emerging field ofinformation processing technology. As ANNs can be taught complex nonlinearinput-output transformations and have the ability of adaptive learning, resistance tonoise and fault tolerance, they can solve the pattern recognition and funtionalmapping problems.
文摘O-Aryl O-ethyl N-isopropyl phosphoramidothioates (Ⅰ) have herbicidal activity. In order to study the relationship between structures and activities of these compounds, more than thirty compounds (Ⅰ) have been prepared by the reaction of O-aryl O-ethyl phosphorochloridothioates with isopropylamine in the presence of 40% NaOH at 0℃. The intermediates, phosphorochloridothioates, were prepared separately from a large excess of O-ethyl Phosphorodichloridothioate and various substituted phenols in the presence of 40% NaOH and a catalyrical amount of Et_3N at 0—5℃. As a result, higher purity and good yields were obtained.It was found that the activity of these compounds was highly dependent upon the substituents attached to the benzene ring with respect to the characteristic parameters π, E_s, σ and F by using Hansch's equation.It was indicated that hydrophobic (π), steric (E_s), and electronic (σ and F) effects of the substituents on the ring in those molecules seem to be of considerable importance in determining their biological activity.By replacing π with △R_m and a and F with △δ_p, respectively, in regression analysis a better correlation was obtained. Both △R_m and △δ_p were experimental data. The former was calculated from R_f measured with reversed-phase thin-layer chromatography and the latter was obtained from the difference between the chemical shifts of the ^(31)P NMR of compounds(Ⅰ) and that of the parent compound.
文摘A computer-assisted retention prediction system (RPS) of fifteen O-ethyl O-aryl N-iso- propyl phosphoramidothioates (1) in reversed-phase HPLC was investigated. The system is based on the use of four physicochemical parameters (hydrophobicity , electric effect σ, field effect F and steric effect ) which is closely related to the retention mechanism in reversed-phase HPLC. The system was evaluated by comparing the measured retention data with the predicted ones. The predicted values were consistent with the measured values within a relative error of 11.5%.
