微波辐射下2-对二甲氨基苯基苯并咪唑的合成及表征

由于具有良好的生物活性,苯并咪唑衍生物或其配合物广泛用于广谱杀菌剂、抗寄生虫药、质子泵抑制剂等药物行业,此外苯并咪唑衍生物还可用作铜铝等金属防腐剂、金属缓蚀剂、光敏剂、无银照相、表面活性剂、催化剂、荧光增白剂及光敏染料等[1～3].     

1-酰基苯并咪唑及3-酰基-2-硫代噻唑烷酮衍生物的合成

苯并咪唑类化合物在杀菌剂研究中已取得可喜的结果,如苯菌灵、多菌灵,具有生物活性的酰基苯并咪唑类化合物已见报道,Richmond等研究发现保护性杀菌剂克菌丹在植物体内被代谢成具有内吸活性的含酰基硫代噻唑烷酮的氨基酸,杀菌和杀线虫剂N-244的结     

有抗病毒活性的苯并咪唑苯氧乙酸乳糖酯的催化合成

苯并咪唑及其衍生物在应用上有许多报道,是广泛使用的驱虫剂、杀真菌剂、植物病毒抑制剂、农用杀菌剂（如多菌灵）,作为医药也有许多报道。芳氧羧酸类化合物是医药、农药、染料的中间体,其中一些还具有杀虫、杀菌、除草和植物激素等多方面的生物活性。     

N-取代苯基-N’-（2-苯并咪唑甲酰基）脲的合成及抑菌活性

许多芳酰基脲类化合物具有良好的杀虫活性,有些还具有一定的杀菌、除草、植物生长调节等生物活性,已成为农药研究和开发的热点。迄今为止,已研制出除虫脲、氟铃脲、灭幼脲、伏虫隆、苏脲1号等20多种商品化的苯甲酰脲类杀虫剂。另一方面,苯并咪唑类化合物,如多菌灵、氰菌灵、麦穗宁等是一类活性很强的内吸性杀菌剂;但是,随着使用时间的延长,病害菌的抗性也越来越强,导致该类杀菌剂活性降低,甚至在一些地区丧失了杀菌能力。因此,研究新型苯并咪唑类杀菌剂具有很大的应用价值。为了寻找具有高效杀菌活性的新型苯并咪唑类化合物,本文利用活性结构拼接原理,将2-苯并咪唑基引入芳酰基脲类化合物的分子中,     

微波辐射快速合成2-(2＇-羟苯基)-5(6)取代苯并咪唑衍生物

苯并咪唑衍生物具有一定的抗病毒能力[1],一些苯并咪唑衍生物已用作农用抗植物病毒剂[2].一锅煮合成反应时间较长,产率中等[3,4].本文用取代邻苯二胺和水杨酸为原料,吡啶为溶剂,POCl3为催化剂,微波辐射法合成了标题化合物.     

相转移催化合成双(2-苯并咪唑)二硫醚化合物

苯并咪唑是一类存在于多种药物中的重要结构单元,许多苯并咪唑类化合物在生物体中,参与了重要的生物化学反应,对生命活动起着重要的作用.有的对植物的生长有一定的作用,有抗病毒作用;有的作为杀菌剂;有的作为螯合剂广泛使用.许多烷基苯并咪唑具有抗维生素B12的活性,其中一些具有抗病毒的性质[1].此外,由于其具有良好的荧光物性,还可作为分子探针[2].苯并咪唑环与镧系元素的配合物有光致发光性能[3].因此,合成具有苯并咪唑结构的化合物对研究开发荧光分子探针、高选择性的催化剂和生物活性化合物有着十分重要的意义.     

微波诱导下2-芳氧甲基苯并咪唑-1-水杨醛乙酰腙衍生物合成及生物活性研究

在微波辐射条件下, 通过2-芳氧甲基苯并咪唑-1-乙酰肼衍生物与水杨醛进行缩合反应, 合成了10种未见文献报道的2-芳氧甲基苯并咪唑-1-水杨醛乙酰腙衍生物. 它们的结构经元素分析, IR, ¹H NMR和¹³C NMR确证. 初步生物活性试验结果表明该系列化合物对小麦幼苗的生长具有明显的调节作用.     

（±）—1—[（2—羟基基—5—甲基苯基）（苯基）甲基]—2—吡啶苯并咪唑的合成及晶体结

自 Hobrecker通过还原 2 -硝基 -4 -甲基乙酰苯胺得到 2 ,5 -二甲基苯并咪唑后 ,苯并咪唑化合物一直NNNCH3HOScheme 1　 Structure of compound 1被人们关注[1] .近年来 ,此类杂环化合物的合成及其生物活性的研究日益成为杂环化学研究的热门课题 [2～ 4 ] .文献 [5～ 9]报道 ,苯并咪唑具有广谱的生物活性及其它用途 .因此 ,对这类化合物的合成及其性质的研究具有广阔的开发前景 .本文通过不对称双Schiff碱中氢原子的重排与成环 ,合成了一种新的外消旋苯并咪唑衍生物 (1 ,结构见 Scheme1 ) ,并报道其晶体结构 .1　实验部分1 .1　仪器与…     

四溴化碳促进下2-(1H-苯并[d]咪唑)-3-芳基丙烯腈的高效合成

2-苯并咪唑-3-芳基丙烯腈衍生物具有广谱的生物活性,同时还是一类重要的合成中间体,在有机合成领域具有广泛的应用.以芳醛和2-氰甲基苯并咪唑为原料,乙醇为溶剂,在四溴化碳促进下,高效合成了2-(1H-苯并[d]咪唑)-3-芳基丙烯腈.反应在回流条件下搅拌5～10 min即可完成,以74%～96%的产率得到目标产物.该方法为2-苯并咪唑-3-芳基丙烯腈衍生物的制备提供了反应条件温和、后处理方便和底物适用范围广的合成策略.     

酰氨基硫脲及其相关杂环衍生物的研究(ⅩⅧ)——5-[5-(3-吡啶)-四唑-2-亚甲基]-2-芳氨基-1,3,4-噻二唑的合成及其抗菌活性

四唑和噻二唑类衍生物具有广泛的生物活性,如抗真菌、抗霉菌、抗肿瘤、抗结核菌,以及促进植物生长等活性,1,4-二取代酰氨基硫脲是合成此类物质的重要原料,为了深入研究同一分子中聚结各种杂环化合物的合成及生物活性。     

铝原子团簇Al5、Al5-和Al5+稳定结构的密度泛函理论研究

采用密度泛函理论的四种方法:杂化密度泛函B3LYP与B3PW91、Perdew-Wang91交换与相关泛函WP91PW91、局域自旋密度近似SVWN,研究了A15、Al5-和Al5+团簇的多种可能结构,找到了它们稳定的结构与自旋态,与已有的理论结果作了比较,并计算了Al5-的绝热与垂直电子离解能、Al5的绝热与垂直电离势,同有关的实验数据比较,符合较好.同时对四种密度泛函方法的计算结果作了一些比较与讨论.     

Theoretical study on infrared vibrational spectra of boric-acid in gas-phase using density functional methods

Density functional theory (DFT) methods with various exchange-correlation functionals such as SVWN, BVWN, BVWN5, BLYP, B1LYP, B3LYP, B3PW91, and BH and H are employed in a theoretical study of molecular boric-acid in gas-phase. In the calculations, the split valence 6-311++G** and 6-31G* basis sets were used. The geometry, zero-point vibrational energies (ZPVEs), and harmonic infrared vibrational (IR) frequencies are predicted. The calculated C_3h-symmetry geometrical parameters are compared with Hartree–Fock (HF) calculation results and experimental data. IR frequencies predicted by the BLYP, B3LYP, and B3PW91 calculations are in good agreement with experimental data. The frequency calculations presented here also suggest that the C_3h-symmetrical structure corresponds to a minimum in the potential energy surface, but neither is D_3h- or C₃-symmetrical structure.     

Experimental and calculated H, C and P NMR spectra of pyridine-2-phosphono-4-carboxylic acid

Pyridine-2-phosphono-4-carboxylic acid (MC1) is a compound that possesses potential neuroactivity. In this work the ¹H, ¹³C and ³¹P NMR spectra of MC1 dissolved in D₂O in solution, in the 1.5-9.0 pD range, are presented. Theoretical calculations of the NMR spectra, as well as structural parameters of expected compounds, were performed at the B3PW91/6-311G** and B3PW91/6-31G** level, respectively, for all five possible forms of MC1 (cation, zwitteranion and three anions). Consecutive deprotonation of MC1 and its influence on the structure of the ligand are discussed in detail.     

DFT Calculations and NBO Analysis of 2-Chloroethylethyldichlorosilane Unimolecular Elimination Kinetics in the Gas Phase

Ab initio molecular orbital calculations have been used to investigate the thermal decomposition kinetics of 2-chloroethylethyldichlorosilane at the B3LYP/6-311+G**,B3PW91/6-311+G**,and MPW1PW91/6-311+G** levels of theory.Among these methods,the results(activation parameters) obtained using the B3LYP/6-311+G** level are in good agreement with the available experimental data.The calculated data imply that in the unimolecular β-elimination reactions of the studied compound in the gas phase,the polarization of C(1)-Cl(3) and C(1)-H(4) bonds in the sense of C(1)δ+-Cl(3)δ-and C(1)δ+-H(4)δ-,respectively,is a determining factor in the gas phase elimination reactions 1,2 and 3.Analysis of bond order,natural bond orbital charges,bond indexes,synchro-nicity parameters,and IRC calculations suggest the elimination of 2-chloroethylethyldichlorosilane via reactions 1～3 can be described as concerted and slightly asynchronous.The transition state structures of these reactions are a four-membered cyclic structure.     

Theoretical calculations on the mechanisms of the gas‐phase elimination kinetics of 2‐chloro‐1‐phenylethane, 3‐chloro‐1‐phenylpropane, 4‐chloro‐1‐phenylbutane, 5‐chloro‐1‐phenylpentane,and their corresponding chloroalkanes: The effect of the phenyl ring

The kinetics and mechanisms of the dehydrochlorination of 2‐chloro‐1‐ phenylethane, 3‐chloro‐1‐phenylpropane, 4‐chloro‐1‐phenylbutane, 5‐chloro‐1‐phenylpentane, and their corresponding chloroalkanes were examined by means of electronic structure calculation using density functional theory methods B3LYP/6–31G(d,p), B3LYP/6–31++G(d,p), MPW1PW91/6–31G(d,p), MPW1PW91/6–31++G(d,p), PBEPBE/6–31G(d,p), and PBEPBE/6–31++G(d,p). The potential energy surface was investigated for the minimum energy path. Calculated enthalpies and energies of activation are in good agreement with experimental values using the MPW1PW91 and B3LYP methods. The transition state of these reactions is a four‐centered cyclic structure. The reported experimental results proposing neighboring group participation by the phenyl group was not supported by theoretical calculations. The rate‐determining process in these reactions is the breaking of Cl? C bond. The reactions are described as concerted moderately polar and nonsynchronous. © 2011 Wiley Peiodicals, Inc. Int J Chem Kinet 43: 292–302, 2011     

Manganese(IV) complex with a polydentate Schiff base ligand: synthesis,crystal structure,TDDFT calculation,electronic absorption and EPR spectral study

A six-coordinate Mn(IV) complex, [Mn(H₂L)₂] (1) [H₄L = 2-methoxy-6-(tris(hydroxymethyl)methyliminomethyl)phenol], was synthesized and characterized by elemental analysis, single-crystal X-ray crystallography, FTIR, UV–Vis electronic absorption, and EPR spectroscopy. The single-crystal structural determination reveals that the complex crystallizes in tetragonal space group P4₁2₁2 and the tridentate Schiff base ligands are arranged in mer configuration chelating manganese, which exhibits as slightly distorted octahedral coordination sphere with a N₂O₄ chromophore. Weak hydrogen bonding interactions of uncoordinated hydroxyl groups result in a 2-D supramolecular structure. The UV–Vis electronic absorption and IR spectral data of 1 have been compared with the results obtained by employing DFT and time-dependent density functional theory calculation using B3LYP, B3PW91, and MPW1PW91 functionals, with 6-31G (d-p) and LanL2MB basis sets. The results of these calculations are functional-dependent and, among those used, B3PW91 proved to better reproduce the experimental results.     

Mycoepoxydiene核磁共振谱的理论研究

用密度泛涵理论(Density Functional Theory,DFT)的B3PW 91方法在6-311G**基组下优化了标题化合物mycoepoxyd iene的几何构型,同时计算了红外光谱.并用规范不变原子轨道(gauge independent atom ic orb ital)G IAO/B3PW 91以及G IAO/HF方法分别在6-311G**,6-311++G**等基组进行了核磁共振谱研究,计算结果与实验结果吻合很好.     

Conformations and energetics of sulfur and selenium diimides

The geometries and energetics of different conformations of sulfur and selenium diimides E(NR)(2) (E = S, Se; R = H, Me, (t)Bu, C(6)H(3)Me(2)-2,6, SiMe(3)) have been studied by using various ab initio and DFT molecular orbital techniques. The syn,syn conformation is found to be most stable for parent E(NH)(2), but in general, the preferred molecular conformation for substituted chalcogen diimides is syn,anti. In the case of E(NH)(2) the present calculations further confirm that syn,syn and syn,anti conformations lie energetically close to each other. From the three different theoretical methods used, B3PW91/6-31G proved to be the most suitable method for predicting the geometries of chalcogen diimides. The optimized geometrical parameters are in a good agreement with all available experimental data. While qualitative energy ordering of the different conformations is independent of the level of theory, the quantitative energy differences are dependent on the method used. The performance and reliability of higher level ab initio calculations and DFT methods using large basis sets were tested and compared with experimental information where available. All of the higher level ab inito methods give very similar results, but the use of large basis sets with the B3PW91 method does not increase the reliability of the results. The combination of CCSD(T)/cc-pVDZ with the B3PW91/6-31G-optimized geometries is found to be the method of choice to study energetic properties of chalcogen diimides.     

Calculated gas-phase infrared spectra of 2,2,5,5,8,8-hexamethylhexahydroimidazo [1,2-a]-pyrazine-3,6-dione: relative performance of Hartree-Fock and hybrid density functional theory methods.

Geometric parameters and IR spectra of 2,2,5,5,8,8-hexamethylhexahydroimidazo[1,2-a]pyrazine-3,6-dione were computed by the HF, B3LYP, B3P86 and B3PW91 methods with the 6-31G(d) basis set. All the computation methods produce a boat conformation of the six-membered ring with the orientation opposite to the one experimentally observed, that is obviously due to incapability of such calculations to take into account mutual influence of the molecules in a crystal package. Quality of predicting the interatomic distances observed experimentally decreases in the series HF, B3LYP, B3PW91 and B3P86; for bond angles, in the series B3LYP, P3PW91, B3P86 and HF. At the same time, the IR spectra computed are in a good agreement with the observed FTIR spectrum. The correlation between the calculated and experimental vibration frequencies is characterized by the coefficients higher than 0.9999 for all three DFT methods; for HF it is slightly lower than 0.9995. The calculated absolute band intensities satisfactory match the observed relative intensities as well. Optimal uniform scaling factors calculated are 0.8973, 0.9593, 0.9540 and 0.9552 for HF, B3LYP, B3P86 and B3PW91, respectively.