Synthesis and Herbicidal Activities of N''-(substituted pyrimidin-2-yl)-N-Substituted Phenoxyacetyl Thiourea Derivatives

Acylthiourea derivatives are well known for a wide range of biological activities likebactericidal, fungicidal, herbicidal, insecticidal action and regulating activity for plantgroWth"'. In recent years, substituted phenoxyacetic acid derivatives have beenreported as highly efficient herbicides4. In this paper. a series of substitutedphenoxyacetyl thiourea containing substituted pyrimidine ring sa~so were synthesizedand tested for their biological activities. All of them are new compounds and…     

Efficient synthesis of optically active α-substituted glutamate analogs possessing α-hydroxymethyl and α-alkoxymethyl groups

Highly enantioselective synthesis of (2R)-α-(hydroxymethyl)glutamate (1), a selective agonist of mGluR2 and 3, was achieved in short steps using an asymmetric version of the Strecker synthesis. This was converted into its α-methoxymethyl- and α-benzyloxymethyl derivatives 2 and 3, possible ligands as tools to investigate glutamate receptors, via protection of the sterically hindered amino group by means of phase transfer catalyst.     

ENDOR spectroscopic and molecular orbital study of the dynamical properties of the side chain in radical anions of ubiquinones Q-1, Q-2, Q-6, and Q-10

The dynamics of the side chain of the radical anions of ubiquinones Q-1 (2,3-dimethoxy-5-methyl-6-[3-methyl-2-butenyl]-1,4-benzoquinone), Q-2, Q-6, and Q-10 have been investigated using electron nuclear double-resonance (ENDOR) spectroscopy. When radicals are produced in the liquid phase, secondary radicals are also formed. The EPR spectra of these additional radicals overlap with the radical of interest. ENDOR spectroscopy was found to be capable for studying the dynamical properties of such conditions. The temperature dependence of the isotropic hyperfine coupling constants of the beta- and gamma-protons of the side chain was measured. The activation energy of the rotation and other dynamical properties of the side chain were calculated assuming that rotation can be modeled by the classical two-jump model. The rotation energy barrier for Q-1 was also determined by the hybrid Hartree-Fock/density functional method UB3LYP with the 6-31G(d) basis set. Calculated results were in good agreement with the experimental results. Despite the numerous parameters affecting the ENDOR linewidth ENDOR spectroscopy was shown to be a potential method for studying the dynamical properties of the mixtures of the radicals. Prominent forbidden transitions appear in the ENDOR spectra when alkali ions are present in the sample. From these transitions measured ENDOR-induced EPR spectra showed an additional doublet and phase transition in electron Zeeman frequency.     

2-苄硫基-5,7-二甲氧基-1,2,4-三唑并[1,5-a]嘧啶的合成研究

2-苄硫基-5，7-二甲氧基-1，2，4-三唑并[1，5-a]嘧啶（Ⅲ）是磺草唑胺（metosulam）及1，2，4-三唑[1，5-a]嘧啶醚类超高效除草剂的重要中间体．由5-氨基-3-苄硫基-1，2，4-三唑（Ⅰ）为起始原料，经环合、氯代一步反应制得2-苄硫基-5，7-二氯-1，2，4-三唑并[1，5-a]嘧啶（Ⅱ）．优化试验发现90℃、丙二酸与（Ⅰ）摩尔比为1．1：1、反应20h时收率达85％以上．（Ⅱ）与甲醇钠进行置换反应制得（Ⅲ），对反应温度和物料配比进行了优化试验，发现25℃、甲醇钠与（Ⅱ）的摩尔比为5：1时收率达到90％以上．中间体（Ⅱ）、（Ⅲ）的结构经^1H-NMR、MS、IR确证．该方法原料易得、操作简便，总收率较高．     

噻唑并[3,2-a]嘧啶衍生物的合成及其在水介质中识别Fe3 的性能

噻唑[3,2-a]并嘧啶衍生物具有多种生物活性,但其较差的溶解性限制了其应用。本文在7-(3-氨基苯并呋喃-2-基)-噻唑并[3,2-a]嘧啶-5-酮的芳香环上引入三乙二醇单甲醚,成功合成了化合物L,并利用核磁、质谱对其结构进行了表征。在pH 3.4~6.4范围内,化合物L可在HEPES水溶液中荧光"开-关"识别Fe~(3+),其他金属离子对识别作用没有干扰,该荧光探针具有较高的选择性和较低的检测限。     

Synthesis of N1-Substituted 1,2,3,6-Tetrahydropyrimidin-2-ones via an Unexpected Reaction of Thiazolo[3,2-a]-pyrimidine Derivatives and Nitrile Oxide

A new class of N1‐substituted 1,2,3,6‐tetrahydropyrimidin‐2‐ones was prepared in moderate yields by the reaction of nitrile oxide with thiazolo[3,2‐a]pyrimidine derivatives via a domino 1,3‐dipolar cycloaddition/ring‐opening/ substitution process. The structures of the products were characterized thoroughly by IR, elemental analysis, MS, NMR together with X‐ray crystallographic analysis.     

Sinularia属珊瑚中嘧啶类化合物的分离与鉴定

分离和鉴定了采自中国南海硇州岛软珊瑚Sinularia Bassica样本中新的嘧啶类化合物。样本用工业酒精提取,提取物溶液经乙酸乙酯萃取后,萃取物经硅胶柱层析,以极性不断增大的溶剂体系(石油醚-乙酸乙酯、氯仿-甲醇)梯度洗脱,再经过HPLC分离,得到2,4(1H,3H)-嘧啶二酮、5-甲基-2,4(1H,3H)-嘧啶二酮、1,3-二甲基-2,4(1H,3H)-嘧啶二酮和5-甲氧基-1,3-二甲基-2,4(1H,3H)-嘧啶二酮4种新的嘧啶类化合物,其结构通过红外光谱、1HNMR和13C NMR等光谱数据分析确定。     

Very Low Energy Electrons Transform the Cyclobutane‐Pyrimidine Dimer into a Highly Reactive Intermediate

Electrons with virtually no kinetic energy (close to 0 eV) trigger the decomposition of cytotoxic cyclobutane‐pyrimidine dimer (CPD) into a surprisingly large variety of fragment ions plus their neutral counterparts. The response of CPD to low energy electrons is thus comparable to that of explosives like trinitrotoluene (TNT). The dominant unimolecular reaction is the splitting into two thymine like units, which can be considered as the essential molecular step in the photolyase of CPD. We find that CPD is significantly more sensitive towards low energy electrons than its thymine building blocks. It is proposed that electron attachment at very low energy proceeds via dipole bound states, supported by the large dipole moment of the molecule (6.2 D). These states act as effective doorways to dissociative electron attachment (DEA).