微波辅助铜合成2-(N,N-二甲氨基)苯并噁唑衍生物

建立了一种简单实用、经济高效的以取代2-碘芳胺和N,N-二甲基氨基硫代甲酰氯为原料,以碘化亚铜为催化剂,吡啶为溶剂,100 ℃条件下,串联合成2-(N,N-二甲氨基)苯并噁唑衍生物的微波催化体系,合成了一系列中等至良好产率的2-(N,N-二甲氨基)苯并噁唑衍生物,最高产率达90%。     

羟基取代乙二胺衍生物与醛反应化学选择性合成取代苯并噁嗪和咪唑啉（英文）

在La(OTf)_3的催化作用下,羟基取代乙二胺衍生物与醛通过环化反应,高化学选择性、高效地合成多官能团取代的1,3-咪唑啉和3,1-苯并噁嗪类化合物.脂肪醛和芳香醛都适用于该反应体系.探索了可能的反应机理,O原子和N原子的亲核性对反应的化学选择性起着非常重要的作用.该方法的优点是只需调节羟基取代乙二胺分子中亚甲基的位置,就可以高化学选择性地合成1,3-咪唑啉或3,1-苯并噁嗪类化合物.     

“受阻路易斯酸碱对”催化的2,3-二取代2H-1,4-苯并噁嗪氢化反应机理研究

在受阻路易斯酸碱对（FLPs）催化的2，3-二取代2H-1，4-苯并噁嗪氢化反应中，3号位取代基不同会导致反应效率极大改变，因此我们选取反应活性具有较大差别的三种底物作为模型化合物对其反应机理进行了研究，建立了氢化反应势能面.发现当B（C₆F₅）₃与2，3-二苯基2H-1，4-苯并噁嗪或2-甲基-3-苯基2H-1，4-苯并噁嗪混合后，会形成FLPs与路易斯酸碱加合物的混合物.而将B（C₆F₅）₃与2，3-二甲基2H-1，4-苯并噁嗪混合后主要形成没有催化活性的路易斯酸碱加合物，因其能量低于FLPs，在催化体系中不容易转化为FLPs，这导致三种模型化合物在FLPs催化的氢化反应中效率不同.进一步的取代基电子效应及位阻效应计算表明：B（C₆F₅）₃与2-甲基-3-取代2H-1，4-苯并噁嗪混合后形成的路易斯酸碱加合物和FLPs化合物之间稳定性差别源于3位取代基空间位阻不同.     

含噻二唑基硫脲类化合物的合成

以噻二唑-2-氨甲基酚(1)为原料, 与异硫氰酸苯酯反应, 以中等到良好的产率得到噻二唑基N-苯基取代硫脲类化合物(3a~3i); 而化合物1与活性较高的N,N-二甲胺基硫代甲酰氯反应, 则可以得到—NH和—OH同时反应的含有N,N-二甲基硫脲和N,N-二甲基硫代氨基甲酸芳酯官能团的产物. 利用核磁共振、 红外光谱以及高分辨质谱等手段对产物结构进行了表征.     

七水合三氯化铈-碘化钠催化氨基苯硫酚与高位阻α, β-不饱和酮的迈克尔加成反应

对七水合三氯化铈-碘化钠(CeCl₃·7H₂O-NaI)化邻氨基苯硫酚、 对氯邻氨基苯硫酚、 间氨基苯硫酚、 对氨基苯硫酚和对甲基苯硫酚与α,β-不饱和酮(1a~1o)的迈克尔加成反应进行了系统研究. 结果表明, CeCl₃·7H₂O-NaI-SiO₂复合催化剂能有效催化邻氨基苯硫酚及对氯邻氨基苯硫酚与α,β-不饱和酮(1a~1o)的迈克尔加成反应. 在优化的反应条件下, 即n(CeCl₃·7H₂O):n(NaI):n(α,β-不饱和酮)=1:2:2, m(CeCl₃·7H₂O):m(SiO₂)=1:1.6, 三氯甲烷作溶剂, 反应温度为回流温度, 反应时间为2 h, 反应可达到中等产率(43.1%~58.8%). 催化剂重复使用4次基本稳定. 此外, 提出了可能的催化机理.     

反-2,3,6(8)-三取代-1,3-苯并噁嗪类化合物的立体选择性合成、晶体结构与杀菌活性

在TMSCl的催化作用下,2-芳氨基甲基苯酚和取代苯甲醛经N,O-缩醛反应合成了一系列新型反-2,3,6(8)-三取代-1,3-苯并噁嗪类化合物,收率为38%~80%.该反应呈现出高度反式选择性.产物结构用1H NMR,13C NMR,IR和元素分析等进行了表征.对目标化合物进行了杀菌活性测试,在测试浓度下,大部分显示中等至良好的活性.其中化合物5d和5f在浓度为50?g/m L时抗稻瘟病菌的活性达78.6%.     

磷酸特地唑胺的合成新方法

以(5R)-3-(4-溴-3-氟苯基)-5-羟甲基噁唑烷-2-酮为起始原料,在[PdCl₂(dppf)]·CH₂Cl₂催化下与联硼酸频那醇酯反应得到硼化物,继而与5-溴-2-(2-甲基-2H-四唑-5-基)吡啶进行Suzuki反应得到特地唑胺,收率82.9%。 分别考察了催化体系对硼化反应和Suzuki反应的影响,确定了较佳的反应条件。 特地唑胺与二苄基N,N-二异丙基亚磷酰胺反应得到二苄基保护的磷酸特地唑胺,随后经Pd/C脱苄得到磷酸特地唑胺,总收率66.2%。     

2,3-二芳基-1,3-苯并噁嗪的合成及杀菌活性

在三甲基氯硅烷(TMSCl)的催化作用下,取代苯甲醛与邻(芳胺甲基)苯酚经N杂缩醛化反应生成了一系列2,3-二芳基-1,3-苯并噁嗪类化合物。 目标化合物的结构用IR、¹H NMR、¹³C NMR和元素分析等技术手段进行了表征。 对所合成的化合物进行了初步杀菌活性测试,部分表现出良好的杀菌活性,化合物6e对菌核病菌的抑制活性为79.0%,化合物6a和6d均为74.8%,化合物6e对灰霉病菌的抑制活性为77.9%。     

"一锅法"N-(2-苯甲酰胺苯基)-水杨醛亚胺/TiCl4·2THF催化乙烯聚合

报道了4个含苯甲酰胺取代的水杨醛亚胺配体: N-(2-苯甲酰胺苯基)-水杨醛亚胺(L1)、 N-(2-苯甲酰胺苯基)-3-甲基水杨醛亚胺(L2)、 N-(2-苯甲酰胺苯基)-3-叔丁基水杨醛亚胺(L3)和N-(2-苯甲酰胺苯基)-3,5-二溴水杨醛亚胺(L4)的合成, 采用 ¹H NMR和HRMS对其结构进行了表征. 在助催化剂甲基铝氧烷(MAO)作用下, 以L3与TiCl₄·2THF为模型催化体系, 在最佳陈化条件(陈化温度为25 ℃, 陈化时间为30 min, 配体与TiCl₄·2THF的摩尔比3∶1)下, 考察了L1~L4/TiCl₄·2THF催化体系Al/Ti摩尔比、 反应时间、 反应温度和聚合压力, 以及配体结构等对乙烯聚合的影响. 结果表明, 随着在水杨醛骨架上氧原子邻位取代基位阻的增大, 催化体系的活性及所得聚乙烯的分子量均有增加, 其中以L3的催化活性最高, 达到224 kg PE/(mol Ti?h). 采用高温 ¹H NMR, ¹³C NMR, GPC-IR和DSC等对由不同配体L1~L4/TiCl₄·2THF得到的聚乙烯样品的微观结构与热性能进行了分析与表征, 结果显示样品为线性高密度聚乙烯, M_n=5.9×10 ⁴~11.9×10 ⁴, 分子量分布(PDI)为21.9~72.1.     

钯催化三组分烯丙基串联反应:化学专一性合成N-酰亚甲基-2-吡啶酮

N-酰亚甲基-2-吡啶酮是一类非常重要的结构单元, 广泛存在于天然产物和其它具有生物活性的化合物中. 其合成通常是通过2-羟基吡啶与相应的亲电试剂发生分子间亲核取代反应. 然而, 由于2-羟基吡啶的双亲核特性, 这一方法往往面临着N/O化学选择性难以控制的问题. 报道了一例钯催化三组分烯丙基取代反应, 化学专一性地合成难以构建的大位阻N-酰亚甲基-2-吡啶酮衍生物, 收率最高可达98%, 未见有O-烷基化副产物的生成. 该反应可以在克级规模下进行, 依然取得98%的收率. 本方法所得到的N-酰亚甲基-2-吡啶酮产物经过简单转化, 可方便地制得含吡啶酮结构的非天然氨基酸类化合物. 实验结果显示, 该三组分反应是经过一个串联的亲核取代和烯丙基取代反应而专一性地合成N-酰亚甲基-2-吡啶酮衍生物.     

Site-recognition of one of the two alkoxy carbonyl groups present in the dienophile for Diels–Alder reaction

Recognition of one alkoxy carbonyl group from the two in a molecule by a Lewis acid was investigated using 1a–e in the Diels–Alder reaction with diene 6. Combination of 1a and BF₃·OEt₂ provided the highest efficiency to afford 7a, thus showing evidence for the site-selective coordination of BF₃·OEt₂ to the MOM-oxy carbonyl group in 1a. Furthermore, the generality and high reactivity of this combination were confirmed with dienes 11–14.     

Copper(I)-catalyzed reaction of acylzirconocene chloride: cross-coupling and conjugate addition

For the purpose of exploring a new reaction of acylzirconocene chloride as an acyl anion donor, Cu(I)-catalyzed cross-coupling and conjugate addition reactions of acylzirconocene chloride were studied. The coupling reaction with allylic or propargylic halides efficiently proceeded to yield β,γ-unsaturated ketone or allenyl ketone derivatives, respectively. The conjugated addition reaction to ,β-enones was carried out in the presence of 2 equiv. of BF₃·OEt₂ giving 1,4-diketone compounds.     

Synthesis of novel benzo[b]pyrimido[4',5':5,4]thieno[2,3-e][1,6]naphthyridine-8-ones via Pictet–Spengler cyclization

An efficient method for the synthesis of novel benzo[b]pyrimido[4',5':5,4]thieno[2,3e]-[1,6]naphthyridine-8-one derivatives via Pictet–Spengler cyclization is reported. The reaction of 4-(3-aminopyrimido[4,5-d]thieno-2-yl)quinoline-2-ones, which could be obtained from Thorpe–Ziegler isomerization of 4-bromomethylquinoline-2-ones and 5-cyano-1,6-dihydro-4-methyl-2-phenyl-6-thioxopyrimidine,with aromatic aldehydes in the presence of BF_3·OEt_2 gives pyrimidothieno[1,6]naphthyridines in good yields.     

Reactions of metalloalkynes VII. Protonation of ruthenium ethyne-1,2-diyl complexes

The acid–base chemistry of some ruthenium ethyne-1,2-diyl complexes, [{Ru(CO)₂(η-C₅H₄R)}₂(μ₂-CC)] (R=H, Me) has been investigated. Initial protonation of [{Ru(CO)₂{η-C₅H₄R}}₂(μ₂-CC)] gave the unexpected complex cation, crystallised as the BF₄ salt, [{Ru(CO)₂(η-C₅H₄R}}₃(μ₃-CC)][BF₄] (R=Me structurally characterised). This synthesis proved to be unreliable but subsequent, careful protonation experiments gave excellent yields of the protonated ethyne-1,2-diyl complexes, [{Ru(CO)₂{η-C₅H₄R)}₂(μ₂-η¹:η²-CCH)](BF₄) (R=Me structurally characterised) which could be deprotonated in high yield to return the starting ethyne-1,2-diyl complexes.     

Lewis acid BF3·OEt2-catalyzed Friedel–Crafts reaction of methylenecyclopropanes with arenes

Methylenecyclopropanes react with various arenes to give the Friedel–Crafts reaction products in good yields in the presence of Lewis acid BF₃·OEt₂.     

Metal complexes of sterically hindered pyrzolylpyridines. The single crystal X-ray structure of [Cu(L)2]BF4 (L = 1-{pyrid-2-yl}-3-{2′,5′-dimethoxyphenyl}pyrazole)

Reaction of potassium 3{5}-(3′,4′-dimethoxyphenyl)pyrazolide with 2-bromopyridine in diglyme at 130°C for 3 days followed by an aqueous quench, affords 1-{pyrid-2-yl}-3-{3′,4′-dimethoxyphenyl}pyrazole (L²) in 69% yield after recrystallization from hot hexanes. Complexation of [Cu(NCMe)₄]BF₄ by 2 molar equivalents of 1-{pyrid-2-yl}-3-{2′,5′-dimethoxyphenyl}pyrazole (L¹) or L² in MeCN at room temperature, followed by concentration and crystallisation with Et₂O, gives [Cu(L)₂]BF₄ L = L¹, L²) in good yields. Treatment of AgBF₄ with L¹ or L² in MeNO₂ similarly gives [Ag(L)₂]BF₄ L = L¹, L²); reaction of AfBF₄ with L² in MeCN gives a product of stoichiometry [Ag(L²)(NCMe)]BF₄. The ¹H NMR spectra of the [M(L)₂]BF₄ complexes show peaks arising from a single coordinated environment. The single crystal X-ray structure of [Cu(L¹)₂]BF₄ shows a tetrahedral complex cation with Cu---N = 2.011(8), 2.036(8), 2.039(8), 2.110(8) Å. The Cu^I centre is close to tetrahedral, the dihedral angle between the least-squares planes formed by the Cu atom and the N donor atoms of the two ligands being 88.3(3)°. Complexation of hydrated Cu(BF₄)₂ by L² in MeCN at room temperature yields [Cu(L₂)₂](BF₄)₂. The cyclic voltammograms of the three Ag^I complexes in MeCN/0.1 M Bu₄ⁿ NPF₆ are suggestive of extensive ligand dissociation in this solvent.     

Synthesis of substituted pyrrolidines by sequential radical cyclization and N-acyliminium ion reactions

Readily available N-acyl-2-pyrrolines are converted into functionalized -alkoxy-β-iodopyrrolidines by N-iodosuccinimide promoted alcohol addition to the enamine group. These compounds are readily cyclized using a sodium cyanoborohydride-catalytic tributylstannane system affording functionalized pyrrolidines in good yields. The cyclized products undergo N-acyliminium ion reactions, such as BF₃·OEt₂ mediated addition of allyltrimethylsilane.     

Biphasic asymmetric hydroformylation and hydrogenation by water-soluble rhodium and ruthenium complexes of sulfonated (R)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl in ionic liquids

A biphasic catalytic system with water-soluble rhodium complexes of sulfonated (R)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (labeled as (R)-BINAPS) in ionic liquid BMI·BF₄ has been developed for the asymmetric hydroformylation of vinyl acetate under mild conditions. The corresponding ruthenium complexes have been investigated for the biphasic asymmetric hydrogenation of dimethyl itaconate. The biphasic asymmetric hydroformylation of vinyl acetate provided 28.2% conversion and 55.2% enantiomeric excess when BMI·BF₄–toluene was used as the reaction medium at 333 K and 1.0 MPa for 24 h. The biphasic asymmetric hydrogenation of dimethyl itaconate in BMI·BF₄–ⁱPrOH at 333 K and 2.0 MPa afforded 65% enantiomeric excess with an activity similar to the homogenous analogs. Both biphasic catalytic systems with (R)-BINAPS ligand could be reused several times without significantly decrease in the activity, enantio- and regio-selectivities. The effects of properties of ionic liquid, molar ratio of ligand to rhodium, temperature, pressure and reaction time have been discussed.     

Fluorination of C6F5MX3 compounds (M=Si, Ge; X=F, Cl, Br, Alk) with xenon difluoride and XeF Y salts

Compounds of the formula C₆F₅MX₃ (M=Si, Ge; X=Cl, Br) react with XeF₂, exchangingchlorine (bromine) atoms for fluorine. Interaction of C₆F₅MX₃ (X=F, Alk) with XeF₂ inthe presence of BF₃·OEt₂ or with XeF⁺ NbF₆^- proceeds by the addition of two fluorineatoms to the pentafluorophenyl ring.