有机碱介入的芳香羧酸氧钒催化过氧化氢氧化茴香脑

以N,N-二甲基甲酰胺(DMF)及杂环氮碱为添加剂,研究了有机碱对芳香羧酸氧钒催化过氧化氢氧化茴香脑制备茴香醛的调变作用.考察了催化剂性质、添加剂种类、DMF用量和反应时间等因素对茴香脑选择氧化的影响,发现DMF作为温和的Lewis碱与pH值调节剂,对茴香脑的转化及主产物茴香醛的选择性具有明显的调控作用.结果表明,以化...     

电化学氧化法合成茴香醛（Ⅲ）──茴香脑合成茴香醛的反应动力学

报道了茴香脑电氧化合成茴香醛的表现活化能（约２３ｋＪ／ｍｏｌ）、反应控制步骤和反应历程，导出了符合一级反应的速率方程。     

电化学氧化法合成茴香醛（Ⅰ）

介绍了茴香醛的合成和利用。报道了以对甲苯酚为原料，用池外式间接电化学氧化法合成茴香醛的最佳条件。电氧化再生媒质的电流效率达９４．０～９５．０％。     

对甲基茴香醚和茴香醛的气相色谱法分离分析

采用OV 101毛细柱对由对甲基茴香醚间接电氧化合成茴香醛的产物进行了分离分析,内标法定量,苯甲酸乙酯为内标物,反应物对甲基茴香醚和产物茴香醛均在0.5～4.0g/L范围内呈良好的线性关系,检测限分别为8.1ng和12.4ng。     

茴香醛的直接电氧化合成研究

应用循环伏安和恒电位电解法研究了茴香醚在铂电极上直接电氧化行为.考查扫描速率、反应底物浓度、支持电解质和溶剂对该电氧化行为的影响.结果表明,茴香醚在铂电极上的氧化过程是不可逆的.在硫酸/丙酮溶液中,其响应峰电流最高,反应受扩散控制.经GC-MS检测,主要氧化产物为茴香醛,选择性为66.5%.     

HPLC间接测定电氧化合成中的茴香醛二甲基缩醛

在无水KF-CH3OH体系中直接电氧化合成的茴香醛二甲基缩醛(p-MBDMA)遇水易发生水解。研究表明在甲醇、乙腈和水的酸性混合溶液中,p-MBDMA在色谱柱中能迅速彻底地水解为茴香醛,故利用其水解反应建立了一种间接测定p-MBDMA的高效液相色谱(HPLC)方法。选择最佳流动相为水-甲醇-乙腈(50:30:20),用磷酸调节pH值至3.0,并探讨了测定机理。建立的HPLC测定方法准确、可靠,已应用于电化学合成p-MBDMA的分析,并可满足工业化生产的分析要求。     

芳香醛电合成的研究 Ⅷ 茴香醛合成反应的动力学

测定了3～40℃范围内不同温度下Ce4+氧化对甲氧基甲苯(MT)制茴香醛(AA)反应的速率常数,并确定了该反应的速率方程为d[AA]/dt=k[MT][Ce4+],表观活化能为31.4±1.3kJ·mol-1.     

自支撑CNTs/SMF-Ni电极上电催化氧气氧化茴香醚合成茴香醛

以具有三维开放网络结构的薄层大面积烧结8 μm金属纤维(SMF-Ni, SMF-SS(316L不锈钢))为基底, 通过乙烯催化化学气相沉积在金属纤维表面生长碳纳米管(CNTs)的方法, 制备了整体式CNTs/SMF-Ni (CNTs: 50% (w))和CNTs/SMF-SS (CNTs: 40% (w))复合材料. 研究表明, 以CNTs/SMF-Ni 为阴极材料、SMF-SS为阳极材料, 具有很高的直接电催化氧气氧化对甲氧基甲苯(茴香醚)合成对甲氧基苯甲醛(茴香醛) 的活性, 反应物转化率和产物选择性分别达95.4%和96.5%, 电流效率可超过80%.     

间氨基茴香醚的合成

以间氨基苯酚为原料,经乙酰化、甲基化和碱水解合成了间氨基茴香醚,3步反应的收率分别为90.7%,82.8%和88.2%。最佳的甲基化反应条件为:间羟基乙酰苯胺56 mmol,n(间羟基乙酰苯胺)∶n(M e2SO4)∶n(NaOH)=1.0∶1.5∶1.2,回流反应8 h,四氯化碳为溶剂。     

电化学氧化法合成茴香醛（Ⅱ）

研究了茄香脑电氧化合成茄香醛的最佳条件：以乙醇和水为溶剂，以含１．９％茄香脑和１．６％ＮＨ４ＮＯ３（支持电解质）的乙醇溶液作阳极液；不含茄香脑的混合溶液的阴极液。溶液ＰＨ＝１－２，池温２５－２８℃，控电流电解，电流效率６０－６２％，反应总级数ｎ＝１。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.