Huazheng Yang

Enantioseparation of fourteen O-ethyl O-phenyl N-isopropyl phosphoroamidothioates by high-performance liquid chromatography on a chiral stationary phase

Abstract A series of fourteen O-ethyl O-phenyl N-isopropyl phosphoroamidothioate enantiomers containing a phosphorus atom as a chiral center have been separated by high-performance liquid chromatography on a Pirkle model chiral stationary phase. Chromatography data, the capacity factor (k′) and the separation factor (α) of all solutes are presented. The influence of chromatographic conditions was investigated. The probable mechanism for chiral recognition is proposed.

QSAR and 3D-QSAR analysis of structurally diverse ALS inhibitors: sulfonylureas and triazolopyrimidine-2-sulfonamides

For the purpose of better understanding the molecular mechanism of action of sulfonylurea and sulfonamide herbicides, the quantitative relationship between their structure and herbicidal activity against rape, Brassica campestris L, was analysed using physicochemical parameters and regression analysis and comparative molecular field analysis (CoMFA). The results showed that the structure–activity relationships of the two sets of compounds were identical, which suggested that the two different sets of compounds affect a common region of the receptor site. The CoMFA results were consistent with those derived from traditional QSAR analysis. Combining the traditional QSAR analysis with the CoMFA results, we can conclude that the variations in the herbicidal activity of the two sets of ALS inhibitors were governed dominantly by the three-dimensional steric and electrostatic field parameters of molecules participating in the interaction with the receptor site and there is apparently an optimum electronic property (Σσ or pKa) for the molecules to fit the receptor. © 1999 Society of Chemical Industry

Synthesis and insecticidal activities of novel pyrazole oxime ether derivatives with different substituted pyridyl rings

BACKGROUND Pyrazole oxime ether derivatives with different substituted pyridyl rings represent new types of compounds that possess good insecticidal and acarcidal activity against Aphis laburni Kaltenbach and Tetranychus cinnabarinus. RESULTS In total, 82 novel pyrazole oxime ether derivatives were synthesized and identified by (1) H NMR, elemental analysis or high-resolution mass spectrometry, and their insecticidal and acarcidal activities were tested against A. laburni Kaltenbach and T. cinnabarinus. Bioassays showed that at a 200 mg L(-1) dosage, one-third of the compounds displayed high insecticidal activity against A. laburni Kaltenbach (> 90%), whereas most of of the compound II series exhibited excellent acarcidal activity against T. cinnabarinus (> 92%). Most compound II series exhibited good activity in both insecticidal and acarcidal tests. In addition, at a low concentration of 10 mg L(-1) , the insecticidal activity of compounds IB9 and IE4 exceeded 90%, and the acarcidal activity of compounds IIB1 and IIB2 was ≥ 95%. CONCLUSION Structure-activity relationships were also examined. Results suggested that the tert-butoxycarbonyl group, as well as the position between tert-butoxycarbonyl and the atom N of the pyridyl ring, were essential to obtaining the acarcidal activity of the title compounds.

Efficient Construction of Pyrazolo[1,5-a]pyrimidine Scaffold and its Exploration as a New Heterocyclic Fluorescent Platform

An efficient, fast and facile pyrazolo[1,5-a]pyrimidine synthetic protocol has been established by the condensation of aminopyrazoles with 1,3-dicarbonyl components in AcOH/H2SO4 system. The pyrazolo[1,5-a]pyrimidine sulfides were selectively oxidized to the sulfones via a temperature-controlled stepwise oxidative fashion. The correlation between the substitution patterns of these pyrazolo[1,5-a]pyrimidines and their fluorescent spectroscopic properties were further examined, which provided the fundamentals for their potential applications in the development of new fluorescent probes. Red-shifts were easily achieved by the incorporation of unsaturated groups at the 5- and 7-positions, which suggested an approach for synthesizing long wavelength pyrazolo[1,5-a]pyrimidine dyes. The fluorescent spectroscopic properties were found to be sensitive to the hydroxy-containing and carbonyl-containing media such as alcohol and acetone, which helps to confirm the promising perspectives of further investigations in this area.

SYNTHESIS OF NOVEL DERIVATIVES OF 2-CYANO-3-METHYLTHIO-3'-BENZYLAMINO ACRYLATES(ACRYLAMIDES) AND THEIR BIOLOGICAL ACTIVITY

Abstract A series of new substituted derivatives of 2-cyano-3-methvlthio-3′-aminoacrylates(acrylamides) have been designed and synthesized. Their structures were confirmed by 1h NMR and elemental analysis. The bioassay test indicates that most of these new compounds show good Hill reaction inhibitory activity.

The Synthesis and Herbicidal Activity of 1-Alkyl-3-(α-hydroxysubstituted benzylidene)pyrrolidine-2,4-diones

In the search for better herbicides a series of 1-alkyl-3-(α-hydroxy-(un)substituted benzylidene)pyrrolidine-2,4-diones were prepared and their structure-activity relationships studied. All their structures have been confirmed by 1H-NMR and elemental analysis. The preliminary bioassay results indicated that some of them have high herbicidal activity against annual dicotyledonous and monocotyledonous plants.

Enantiomer separation and preparation of five organophosphorus compounds and their biological activities.

SummaryThe direct enantiomeric resolution of five O-aryl O-alkyl N-alkyl-phosphoramidothioates was carried out and their pure enantiomers were prepared on a commercially available Pirkle model chiral column (OA-4700). Absolute configurations of the enantiomers were determined by circular dichroism (CD) spectroscopy. S-enantiomers were the first compounds to elute chromatographically and the chromatographic elution order was in accordance with the results of computer simulating calculation. The biological activity test suggested that all the S-enantiomers were more active than R-enantiomers in killing barnyard grass.

Wang resin bound addition reactions under microwave irradiation

Abstract The addition reaction process of Wang resin bound amines with isocyanates was monitored directly using a FTIR method. It showed that the reaction process was greatly enhanced under microwave irradiation.

Design, synthesis and bioactivity of novel ALS inhibitors (V)

By means of the X-ray diffraction method, quantum pharmacology analysis and quantitative structure-activity relationships (QSAR) analysis, the structure-activity relationships of the herbicidal sulfonylureas and fused heterocyclic sulfonamides were systematically studied. The results showed that the structure-activity relationships of these two kinds of herbicides were identical and that the heterocyclic ring and sulfonyl moiety in the molecules were their pharmacophores which likely bind in the same receptor sites of acetolactate synthase (ALS). According to these results, the initial model of these two kinds of herbicides binding with the receptor was put forward.

Synthesis and herbicidal activities of novel 3-(substituted benzyloxy or phenoxy)-6-methyl-4-(3-trifluoromethylphenyl)pyridazine derivatives.

BACKGROUND 4-(3-Trifluoromethylphenyl)pyridazine represents a new series of compounds with bleaching and herbicidal activities. RESULTS A total of 43 novel 3-(substituted benzyloxy or phenoxy)-6-methyl-4-(3-trifluoromethylphenyl)pyridazine derivatives were synthesised, and their bleaching and herbicidal activities were evaluated through Spirodela polyrrhiza and greenhouse tests. Some compounds exhibited excellent herbicidal activities, even at a dose of 7.5 g ha(-1). CONCLUSION The results showed that a substituted phenoxy group at the 3-position of the pyridazine ring and the electron-withdrawing group at the para-position on the benzene ring were essential for high herbicidal activity.