Simple and effective preparation of amino sulfonylureas from amino acids: application to the synthesis of amino sulfonylurea-containing peptidomimetics

Several amino sulfonylureas have been synthesized, starting from amino acids. The synthetic procedure is simple affording high yields of products under mild conditions. Furthermore, it is shown that these compounds can be incorporated into a peptide sequence.     

Synthesis and Crystal Structure of Sodium Monosulfuron (N-(4-Methylpyrimidin-2-yl)-N'-2-(nitrophenylsulfonyl) Urea Sodium)

Monosulfuron is a novel sulfonylurea herbicide with ultra-low dosage invented and patented by Nankai University.Herein its sodium salt was firstly synthesized and crystal structure was determined by X-ray diffraction method.The title compound belongs to the triclinic system, space group P1- with a = 7.306(6), b = 9.446(8), c = 11.872(10)(A), α= 76.578(14), β= 78.049(13), γ= 77.620(14)°, V = 767.7(11)(A)3, Mr = 377.32, Z = 2, Dc = 1.632 g/cm3,μ= 0.283 mm-1, F(000) = 388, R = 0.0444 and wR = 0.1186.In the title compound, Na(1) coordinates with O(4) and O(5) from one monosulfuron molecule, N(4A) and O(5A) from the other monosulfuron molecule and the oxygen atom from H2O to give five coordination bonds.The title complex is further linked into a three-dimensional structure through π…π interactions and intermolecular hydrogen bonds between the oxygen and nitrogen atoms.     

Preparation of iron‐based MIL‐101 functionalized polydopamine@Fe3O4 magnetic composites for extracting sulfonylurea herbicides from environmental water and vegetable samples

Here, we describe a simple one‐pot solvothermal method for synthesizing MIL‐101(Fe)@polydopamine@Fe₃O₄ composites from polydopamine‐modified Fe₃O₄ particles. The composite was used as a magnetic adsorbent to rapidly extract sulfonylurea herbicides. The herbicides were then analyzed by high‐performance liquid chromatography. The best possible extraction efficiencies were achieved by optimizing the most important extraction parameters, including desorption conditions, extraction time, adsorbent dose, salt concentration, and the pH of the solution. Good linearity was found (correlation coefficients >0.9991) over the herbicide concentration range 1–150 μg/L using the optimal conditions. The limits of detection (the concentrations giving signal/noise ratios of 3) were low, at 0.12–0.34 μg/L, and repeatability was good (the relative standard deviations were <4.8%, n = 6). The method was used successfully to determine four sulfonylurea herbicides in environmental water and vegetable samples, giving satisfactory recoveries of 87.1–108.9%. The extraction efficiency achieved using MIL‐101(Fe)@polydopamine@Fe₃O₄ was compared with the extraction efficiencies achieved using other magnetic composites (polydopamine@Fe₃O₄, Hong Kong University of Science and Technology (HKUST)‐1@polydopamine@Fe₃O₄, and MIL‐100(Fe)@polydopamine@Fe₃O₄). The results showed that the magnetic MIL‐101(Fe)@polydopamine@Fe₃O₄ composites have great potential for the extraction of trace sulfonylurea herbicides from various sample types.     

Imidazolinone and triazine herbicides in soils in relation to the complexes formed with Cu(II) ions

Imidazolinone and triazine herbicides are used in many countries and may have a great impact on metal biocycles in soil. This article deals with the dynamics of imidazolinone and triazine herbicides in soils related to the formation of complexes with Cu(II) ions, which can be very stable. The stability constants of the complexes formed by five imidazolinone herbicides and ten triazine herbicides with Cu(II) ions are determined by means of fast, easy, and inexpensive measurements performed by ultraviolet–visible spectroscopy, for imidazolinones, and voltammetry (cyclic and differential pulse), for triazines. Because of the occurrence of dissociation reactions, the determinations were performed at three pH values for imidazolinones and at one pH value for triazines. In aqueous solutions of 5 < pH < 10 (corresponding to the majority of soils of agricultural use), the herbicides form very stable complexes with the Cu(II) ions, the complexes being integrated by two ligands (herbicides) and one copper ion. In conclusion, crops treated with such herbicides in conjunction with Cu(II) salts experience a decrease in its persistence and effectiveness. In addition, the herbicides and the copper ions may pass to the phreatic layer of the soil, increasing the chance of pollution.     

Determination of herbicides in environmental water samples by simultaneous in‐syringe magnetic stirring‐assisted dispersive liquid–liquid microextraction and silylation followed by GC–MS

An on‐line, fast, simple, selective, and sensitive method has been developed for the determination of three herbicides belonging to the following families: triazines (atrazine), chloroacetamide (alachlor), and phenoxy (2,4‐dichlorophenoxyacetic acid) in water samples. The method involves an in‐syringe magnetic stirring‐assisted dispersive liquid–liquid microextraction along with simultaneous silylation prior to their determination by gas chromatography with mass spectrometry. Extraction, derivatization, and preconcentration have been simultaneously performed using acetone as dispersive solvent, N‐methyl‐N‐tert‐butyldimethylsilyltrifluoroacetamide as derivatization agent and trichloroethylene as extraction solvent. After stirring for 180 s, the sedimented phase was transferred to a rotary micro‐volume injection valve (3 μL) and introduced by an air stream into gas chromatograph with mass spectrometry detector. Recovery and enrichment factors were 87.2–111.2% and 7.4–10.4, respectively. Relative standard deviations were in the ranges of 6.6–7.4 for intraday and 9.2–9.6 for interday precision. The detection limits were in the range of 0.045–0.03 μg/L, and good linearity was observed up to 200 μg/L, with R² ranging between 0.9905 and 0.9964. The developed method was satisfactorily applied to assess the occurrence of the studied herbicides in groundwater samples. The recovery test was also performed with values between 77 and 117%.     

Research on controllable alkaline soil degradation of 5-substituted chlorsulfuron

Structural modification on the 5^th position of the benzene ring in chlorsulfuron was proved to be an efficient practice to accelerate its degradation in alkaline soil which can resolve the disadvantages of traditional sulfonylurea herbicides. Meanwhile, it could retain high biological activity.     

Development of a rapid, specific fluorescence polarization immunoassay for the herbicide chlorsulfuron

A strategy for design of a derivative of chlorsulfuron, which mimics half of the herbicide molecule, was proposed. The 1-[(2-chloro)phenylsulfonyl]monoamidosuccinic acid was synthesized as a derivative of chlorsulfuron for conjugation to carrier proteins. Rabbits were immunized and the resulting polyclonal antibodies were assessed by the fluorescence polarization technique. The antibodies were highly specific to chlorsulfuron. Cross-reactivity to the structurally similar sulfonylurea and urea herbicides chlorbromuron, amidosulfuron, chlortoluron, isoproturon, diuron and linuron was less than 0.1%. A rapid fluorescence polarization immunoassay (FPIA) for chlorsulfuron detection in water samples was developed and optimized. The detection limit of chlorsulfuron in 50 μl of sample was 10 ng ml⁻¹. Total time for the measurement of 10 samples is 7 min. The proposed FPIA is suitable for rapid testing for pesticide contamination where the highest sensitivity is not critical or in combination with pre-concentration techniques.     

快速基质分散净化-超快速液相色谱-串联质谱法同时测定玉米中22种三嗪类除草剂残留

建立了玉米中扑灭津、莠去津、敌草净、特丁通等22种三嗪类除草剂多残留的分析方法。样品以乙腈为提取剂,经高速匀浆方法提取并浓缩后,以增强型脂质去除净化剂(EMR-Lipid)净化,除去了样品中的脂质,有效地降低了样品中的复杂基质所带来的背景干扰,净化液再经增强型脂质去除萃取剂(EMR-Polish)盐析萃取,以 Kinetex XB-C18柱为分离柱,用乙腈和0.1%甲酸溶液进行梯度洗脱,电喷雾正离子(ESI+)多反应模式监测,超快度液相色谱-串联质谱(UFLC-MS/ MS)测定,基质匹配标准曲线法定量。加标水平为5,10和20μg/ kg 时,22种农药的回收率为72%~105%,相对标准偏差小于15%。22种农药的检出限为0.16~1.8μg/ kg,在1.0~50μg/ L 范围内线性关系良好(r>0.993)。本方法具有快速、准确、灵敏度高等优点,能够准确测定玉米中22种三嗪类除草剂的残留量。     

Controllable Effect of Structural Modification of Sulfonylurea Herbicides on Soil Degradation

The study of soil degradation behaviors of sulfonylurea herbicides in relation to their different structural attributes is utmost important for us to comprehend the development of new eco‐friendly herbicides. It is postulated that the structural modification of the chemical structures could influence their degradation rates in soil. Nine devised structures were synthesized to study their herbicidal activity as well as their soil degradation behaviors respectively. The novel compounds I‐3 – I‐7 were characterized by UV, ¹H NMR and ¹³C NMR, MS and EA. Bioassays indicated that most of target compounds displayed superior herbicidal activities in comparison with Chlorsulfuron. Soil degradation results further confirmed our previous assumption that the introduction of electron‐donating substituents at 5^th position of the benzene ring distinctly increased their degradation rates, among which dimethylamino and diethylamino groups can adjust the degradation rate to a more favorable status.     

Cyclodextrin inclusion of four phenylurea herbicides: determination of complex stoichiometries and stability constants using solution 1H NMR spectroscopy

An inclusion complex formation between α- and β-cyclodextrin and four phenylurea analogues, namely metobromuron, monolinuron, monuron and fenuron, is reported. Complex formation was established using solution ¹H NMR spectroscopy. Complex stoichiometries were determined by the method of continuous variation using the chemically induced shifts of both the host and guest protons. An analysis of the spectroscopic data revealed the stoichiometry as 1:1 in all cases while a further analysis of the same data yielded values for the association constant K ranging from 208 to 2749 M^? 1. From the observed chemical shifts it was deduced that in all cases, only the guest aromatic ring enters the host cavities, the substituted urea moiety protruding from the secondary rim in the case of α-cyclodextrin, but from the primary rim in the case of β-cyclodextrin.