N′-(4,5,6-三取代嘧啶-2-基)-2-噻吩磺酰脲的合成

前文曾报道了15种含4,6—二取代嘧啶环的噻吩磺酰脲类化合物的合成和除草活性测定。初步的结构与生物活性关系的研究表明,嘧啶环上取代基的种类,数目及位置对此类化合物的生物活性影响较大,含4,6—二甲基嘧啶环的噻吩磺酰脲具超高除草活性,含4—羟基—6—甲基嘧啶环或4—氯—6—甲基嘧啶环的噻吩磺酰脲能有效抑制植物根系的生长,而含取代氨基的噻吩磺酰脲的生物活性较差。为进一步研究不同取代基对此类化合物生物活性的影响,本文合成了13种     

苯环2-位不同酯基取代的磺酰脲类化合物的合成及其除草活性

以正在开发的磺酰脲类超高效除草剂NK94827[N'-(4'-甲基嘧啶-2'-基)-2-甲氧羰基苯磺酰脲]的基本结构为基础,设计合成了18个苯环2位不同酯基取代的的新型磺酰脲类化合物,产物结构均经¹HNMR及元素分析确证.经油菜平皿法和盆栽试验测试除草活性,所合成的部分磺酰脲化合物的除草活性高.     

N-(取代嘧啶-2''''-基)-2-三氟乙酰氨基苯磺酰脲的合成及除草活性

磺酰脲类除草剂是近 2 0年来开发出的超高效、广谱、低毒和高选择性除草剂 .在已研究的磺酰脲分子中 ,芳环的邻位取代基多为酯基、卤素、取代烷氧基、三氟甲基等 [1,2 ] ,而邻位取代基为酰胺基的甚少 .为寻找高活性的磺酰脲化合物 ,本文将活性基团三氟乙酰氨基引入磺酰脲分子中 ,合成了 1 0种 N - (取代嘧啶 - 2 -基 ) - 2 -三氟乙酰氨基苯磺酰脲 (其中 9种为新化合物 ,4b～ 4j) ,并改进了实验方法 ,使产率明显提高 .同时还测定了它们的除草活性 ,其中一些化合物具有良好的活性 .合成路线如下 :　　 X- 4数字显示显微熔点仪 ,温度计未校正…     

新(4′-三氟甲基嘧啶基)-2-苯磺酰脲衍生物的合成及生物活性

以单取代苯磺酰脲除草剂NK92825和NK94827为基础,将三氟甲基引入嘧啶环中,设计合成了17个新的4′-三氟甲基嘧啶苯磺酰脲化合物,产物结构均经1H NMR及元素分析确证.目标化合物经盆栽试验,结果表明,部分化合物有较好的除草活性.     

新三取代嘧啶苯磺酰脲衍生物的合成与生物活性

设计合成了22个具有4,5,6-三取代嘧啶磺酰脲衍生物, 其结构经1H NMR, MS和元素分析确证. 经盆栽试验测定了化合物的除草活性, 结果表明, 嘧啶环5位取代基的引入对分子除草活性有一定的影响.     

三氟甲基嘧啶磺酰脲的合成与除草活性

以三氟乙酰乙酸乙酯和盐酸胍为原料,经环合、氯化、甲氧基化、胺化反应合成了4种2-氨基-4-取代-6-三氟甲基嘧啶中间体(Ⅰa~Ⅰd),Ⅰ与邻甲氧羰基苯磺酰异氰酸酯亲核加成,合成了3种含不同取代嘧啶环的磺酰脲化合物(Ⅱb~Ⅱd)。其中2-氨基-4-二甲胺基-6-三氟甲基嘧啶(Ⅰd)和N[-2-(′4-二甲胺基-6-三氟甲基)嘧啶基]-2-甲氧羰基苯磺酰脲(Ⅱd)为新化合物,结构经1H NMR和MS表征。初步除草活性测定结果表明,N-[2-′(4-甲氧基-6-三氟甲基)嘧啶基]-2-甲氧羰基苯磺酰脲(Ⅱc)在浓度为200 ga.i./ha时对稗草和马唐的防效分别为70%和50%。     

新磺酰脲类化合物的合成及生物活性

以正在开发的新磷磺酰脲除草剂N-[2′-(4′-甲基)嘧啶基]-2-硝基苯磺酰脲的研究为基础,设计合成了19个脲桥经修饰的磺酰脲类化合物以及3个新型嘧啶中间体,产物结构经¹HNMR谱及元素分析确证.盆栽试验和离休ALS酶研究结果表明,所合成的化合物均表现出一定的除草活性,部分化合物的除草活性较好.     

含有单取代嘧啶的新型磺酰脲类化合物的设计、合成及除草活性

为了寻找高效的磺酰脲类除草剂, 以商品化磺酰脲类除草剂为基础, 将单取代嘧啶结构引入到分子中, 合成了一系列新型磺酰脲类化合物, 并通过¹H NMR和高分辨质谱确定了其结构. 采用盆栽法和平皿法测试了所有化合物的除草活性以及部分化合物对油菜的IC₅₀值. 结果表明, 一些化合物具有一定的除草活性, 其中化合物7b和7d对油菜和反枝苋具有较好的抑制活性.     

N-(4-取代嘧啶-2-基)苄基磺酰脲和苯氧基磺酰脲的3D-QSAR研究

采用比较分子力场分析(CoMFA)方法,对两类单取代嘧啶类似物、6个N-(4-取代嘧啶-2-基)-2-甲氧羰基苄基磺酰脲(1a～1f)和14个N-(4-取代嘧啶-2-基)-2-取代苯氧基磺酰脲(2a～2n)进行三维定量构效关系(3D-QSAR)研究.建立了一个较为可靠的预测模型.结果表明,分子中苯环邻位、嘧啶环形成氢键的N原子处以及嘧啶环4位和6位附近负电荷增加;苯环邻位乙氧基的CH₂CH₃附近选择带正电的原子;苯环邻位乙氧基附近空间体积增加,而嘧啶环4位甲氧基稍远处取代基的立体位阻不超过此位置,将有利于提高活性.最后解释了修饰磺酰脲的除草剂仍具有较高活性的原因.     

新型苯环5-(取代)苯甲酰胺基苯磺酰脲类化合物的比较定量构效关系研究

采用比较分子力场分析(CoMFA)方法, 对26个新型苯环5-(取代)苯甲酰胺基苯磺酰脲类化合物的除草活性进行了三维定量构效关系(3D-QSAR)研究, 建立了三维定量构效关系CoMFA模型(R²=0.948, F=91.364, SE=0.141). 结果表明, 此类磺酰脲类化合物的除草活性与苯环5位取代基的立体结构和电场性质密切相关. 根据CoMFA模型的立体场和静电场三维等值线图不仅直观地解释了结构与活性的关系, 而且为进一步设计高活性的目标化合物提供理论依据.     

新磺酰脲类化合物的合成及除草活性

新磺酰脲类化合物的合成及除草活性;嘧啶;合成;除草剂     

Novel synthesis approach and antiplatelet activity evaluation of 6-alkylamino-2,4-dialkyl(aryl)thiopyrimidines

A new and efficient procedure has been designed for the preparation of 6-alkylamino-2,4-dialkyl(aryl)thiopyrimidines. The first alkylthio group was introduced into the pyrimidine ring by S-alkylation. The introduction of the second one was successfully achieved using the diazotization-alkylthionation method to afford 2,4-dialkyl(aryl)thio-6-chloropyrimidines. Subsequent nucleophilic displacement by the corresponding amines conveniently gave a series of the target compounds. Thus, the two same or different alkylthio groups were easily introduced into the pyrimidine ring through the two different approaches. The human anti-platelet aggregation activity of the newly synthesized compounds is also described.     

N-(4'-取代嘧啶-2'-基)-2-甲氧羰基-5-(取代)苯甲酰胺基苯磺酰脲化合物的合成及除草活性研究

为进一步寻找高效、安全和对环境更加友好的除草剂, 以商品化除草剂单嘧磺酯为研究基础, 对其结构中的苯环5-位取代基作了结构修饰, 合成了26个未见文献报道的新型N-(4'-取代嘧啶-2'-基)-2-甲氧羰基-5-苯甲酰胺基苯磺酰脲化合物, 通过¹H NMR、质谱及元素分析确定了化合物的结构. 经油菜平皿法及盆栽法测试了所有化合物的除草活性, 结果表明, 当苯环5-位取代基为苯甲酰胺时, 活性较好, 其对双子叶植物的除草活性与商品化的甲嘧磺隆相当.     

取代嘧啶化合物的合成和生物活性研究

合成了14个新型取代嘧啶类化合物,结构经质谱、红外光谱、氢核磁共振光谱和元素分析确证.杀虫、杀菌和除草活性测定结果表明,部分化合物具有良好的杀菌活性.在嘧啶环的2-位上导入二甲氨基时表现出杀菌活性,但在嘧啶环的5-位上有甲基取代基时,杀菌活性下降.在嘧啶的4-位导入苯氧基时,显示出良好的杀菌活性,如化合物3b,3c和3e,苯环上的最优取代基是2-硝基-4-三氟甲基.     

Core-tetrasubstituted naphthalene diimides: synthesis, optical properties, and redox characteristics

2,3,6,7-tetrabromonaphthalene dianhydride has been synthesized by the bromination of naphthalene dianhydride with dibromoisocyanuric acid in excellent yield. The condensation of this dianhydride with 2,6-diisopropylaniline yielded the corresponding tetrabromo-substituted naphthalene diimide (NDI), which is a versatile precursor for the synthesis of core-tetrafunctionalized NDIs. Nucleophilic substitution of tetrabromo NDI with alkoxy, alkylthio, and alkylamino nucleophiles afforded a series of core-tetrasubstituted NDI chromophores that complete the series of previously reported di- and trifunctionalized NDI derivatives. The effects of electronic nature and number of core substituents on the optical and electrochemical properties of NDIs have been investigated by UV-vis and fluorescence spectroscopy and cyclic voltammetry. The absorption maxima (629-642 nm) of tetraamino NDIs are strongly bathochromically shifted compared to those of other core-functionalized NDIs.     

Electron-donating or -withdrawing nature of substituents revealed by the electrochemistry of metal-free phthalocyanines

The effect of substituents on the electrochemistry of metal-free phthalocyanines was examined for 17 phthalocyanine compounds. This work also provides new information about the electron-donating or -withdrawing nature of various substituents, namely, alkoxy, alkylthio, alkyl, alkynyl, phenyloxy, and phenylthio groups attached to the phthalocyanine system, from the viewpoint of electrochemistry. Most of the effects of peripheral and nonperipheral substitution and changes in the ring (pi-conjugated system) size on the electrochemistry of metal-free phthalocyanines can be reasonably explained by considering the energy levels of frontier molecular orbitals of the corresponding compounds, which were obtained by calculations using the semiempirical PM3 method.     

HETEROCYCLIC SULFUR COMPOUNDS LXXXIV: 3-Alkoxy-1,2-dithio-isocoumarins and 3-Alkylthio-1,2-dithio-isocoumarins

Abstract

Reaction of phosphorus pentasulfide with alkyl hydrogen homophthalates or dialkyl homophthalates gives a mixture of 3-alkoxy-1,2-dithio-isocoumarins and of 3-alkylthio-1,2-dithio-isocoumarins; some of these compounds resulting from a migration of an alkoxy or of an alkylthio group.

Oxidation of these dithio-isocoumarins into 2-thio-isocoumarins has been performed either by potassium permanganate or by benzonitrile N-oxide.     

Highly conjugated 4-ring nematic liquid crystals with a lateral alkoxy branch

Three types of liquid crystalline compound containing a 4-ring mesogenic core with a lateral alkoxy chain on one of the inner rings were synthesized, and their mesogenic properties studied. The 4-ring core of these compounds bears an electron-accepting nitro group at one end and an electron-donating alkylamino moiety at or near the other end. Therefore, they are highly coloured and have lambda max 473 nm. One of these three types of compound has a wide enantiotropic nematic range. Twelve homologous analogues in this series with different lengths for the terminal alkyl chain and the lateral alkoxy chain were synthesized and compared.     

Formation of hexagonal columnar phases by heterocyclic pyrimidine derivatives

The synthesis, characterization, and mesomorphic properties of a new type of heteronuclear compounds derived from pyrimidine as core group are reported. These compounds were prepared by condensation reactions of appropriate acetophenones and benzonitriles in the presence of trifluoromethanesulphonic anhydride. They were characterized by 1 H and 13 C NMR spectroscopy and elemental analysis, and their phase transitions characterized and studied by thermal analysis and polarizating microscopy. These compounds exhibit hexagonal columnar (Col h ) phases, as expected for disk-like molecules; the formation of columnar phases was found to be dependent on the numbers of alkoxy side chains attached. For those compounds having the same numbers of flexible side chains attached, the one with a preferred unsymmetric structure exhibited better mesomorphic properties. The observed improved mesomorphic behaviour of these compounds over other similar all-carbon heterocyclic compounds is attributed to the greater polarization of nitrogen atoms in the core ring.