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A computer-assisted retention prediction system (RPS) of fifteen O-ethyl O-aryl N-isopropyl phosphoramidothioates (1) in reversed-phase HPLC was investigated. The system is based on the use of four physicochemical parameters (hydrophobicity II, electric effect σ, field effect F and steric effect Es) 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%.

A series of 2-cyano-3-methylthio-3-substituted methylaminoacrylates were synthesized as herbicidal inhibitors of photosystem II (PSII) electron transport, in order to estimate the effect of fluorine atom, pyridyl group, chirality and ester chain on activity. The important intermediate 2-fluoro-5-aminomethylpyridine was synthesized with high yield. The bioassay results showed that most of title compounds had high herbicidal activity in postemergence treatment. The introduction of an α-methyl into the 3-substituted methylamino could improve the activity notably. The replacement of hydrogen by chlorine or fluorine group and phenyl by pyridyl group showed different effects, and at the same time, the ester chain affected the activity too.

The title compound, C16H23N5O3S, ethyl 5-amino-l-(5′-methyl-l'-t-butyl-4′-pyrazolyl)carbonyl-3-methylthio 1H-pyrazole-4-carboxylate (5) has been synthesized by the treatment of ethyl 2-cyano-3,3-dimethylthioacrylate with 1 -t-butyl-5-methyl-4-hydrazinocarbonylpyrazole (4) in refluxed ethanol. The possible mechanism of the above reaction was also discussed. The results of biological test show that the title compound has fungicidal and plant growth regulation activities.