金属酸盐催化剂对苯酚羟基化反应的活性考察

苯酚羟基化联产邻苯二酚和对苯二酚是一条典型的绿色工艺路线.通过对多种金属酸铁酸盐进行筛选,得出以Fe(NO3)3.9H2O为铁源、Cu(CH3COO)2.H2O为铜源,以氨水为沉淀剂,采用共沉淀法制备的Fe-Cu复合金属酸盐催化剂具有最好的催化活性.结果表明,在水作溶剂,催化剂与苯酚的质量比为1∶100,苯酚初始浓度25%,反应温度65℃,苯酚与双氧水的摩尔比为2的条件下,采用Fe-Cu催化剂,苯酚单程转化率可达25%,苯二酚总选择性在90%左右.通过对铁酸盐催化剂的XRD、IR表征,可以看出,Fe-Cu催化剂具有独特的CuFe2O4尖晶石结构,因而具有不同于其它铁酸盐的衍射峰和吸收峰.另外,Fe-Cu催化剂制备简便、原料廉价易得,因此具有良好的工业应用前景.     

Fe(III)EDTA作为氧化羰化苯酚合成碳酸二苯酯一种有效的氧化还原催化助剂

研究了氧化羰化苯酚合成碳酸二苯酯反应。发现了Fe(III)EDTA 在PdCl2/Fe(III)EDTA/1,4 苯醌/ 四丁基溴化铵催化体系中具有很好的助催化效果。讨论了上述催化体系中的每一组分的作用，并提出了一个催化反应机理。氧化羰化苯酚合成碳酸二苯酯反应的最佳温度为100℃～120℃。当反应在100℃、PCO=2.0MPa、PO2=0.5MPa、苯酚 0.5mol、 PdCl2 0.28mmol、n(PdCl2)∶n(Fe(III)EDTA)∶n(苯醌)∶n(四丁基溴化铵)=1∶1∶10∶40、 4A 分子筛 5.0g、 4h进行时，碳酸二苯酯的产率和选择性分别为8.35%和97.5%。压力越高对生成碳酸二苯酯越有利。     

Fe(III)EDTA作为氧化羰化苯酚合成碳酸二苯酯一种有效的氧化还原催化助剂(英文)

研究了氧化羰化苯酚合成碳酸二苯酯反应。发现了Fe(III)EDTA在PdCl2/Fe(III)EDTA/1,4-苯醌/四丁基溴化铵催化体系中具有很好的助催化效果。讨论了上述催化体系中的每一组分的作用,并提出了一个催化反应机理。氧化羰化苯酚合成碳酸二苯酯反应的最佳温度为100℃~120℃。当反应在100℃、PCO=2.0 MPa、PO2=0.5 MPa、苯酚0.5 mol、PdCl20.28 mmol、n(PdCl2)∶n(Fe(III)EDTA)∶n(苯醌)∶n(四丁基溴化铵)=1∶1∶10∶40、4A分子筛5.0 g、4 h进行时,碳酸二苯酯的产率和选择性分别为8.35%和97.5%。压力越高对生成碳酸二苯酯越有利。     

wo3催化h2o2氧化环己酮合成己二酸

以WO3为催化剂,在无有机溶剂和相转移催化剂的情况下,用H2O2氧化环己酮合成己二酸。探讨了催化剂用量、H2O2用量、反应温度和时间等条件对反应的影响。在优化条件下:n(环己酮)∶n(H2O2)∶n(WO3)=100∶500∶2,反应温度为120℃,反应6 h,己二酸分离收率可达80.3%,纯度为99.8%;催化剂重复使用5次后己二酸收率仍可达70.2%。     

对硝基邻苯二乙醚合成技术研究

以邻苯二酚与溴乙烷为原料、聚乙二醇为相转移催化剂合成邻苯二乙醚,再经过冰醋酸和硝酸硝化得到对硝基邻苯二乙醚。研究了反应温度、反应时间、原料摩尔比和催化剂用量等对反应收率的影响,获得了合成邻苯二乙醚的优化工艺条件:n(C6H4(OH)2)∶n(NaO H)∶n(C2H5Br)=1∶2.6∶2.4,反应温度80℃,反应时间4h,催化剂用量2g,该反应条件下邻苯二乙醚平均收率88%。混酸硝化条件下合成对硝基邻苯二乙醚的较佳工艺条件为n(C10H14O2)∶n(HNO3)=1∶1.2,乙酸25mL,反应时间30min,反应温度20℃,该反应条件下对硝基邻苯二乙醚平均收率为99%。     

Fe/Cu-HMS分子筛选择性催化氧化苯甲醇的研究

采用溶胶-凝胶法,室温条件下合成了不同Cu含量的Fe/Cu-HMS介孔分子筛催化剂,通过X-射线衍射(XRD)、N2吸附-脱附和扫描电镜(SEM)对合成的催化剂进行了表征;在无助剂条件下,以苯甲醇氧化为反应探针,考察了催化剂Fe/Cu-HMS的催化活性。研究表明:铁、铜部分进入分子筛骨架,没有改变分子筛的介孔结构,具有良好的分散性;在80℃反应温度下,苯甲醇与过氧化氢摩尔比为1∶2,Fe/Cu(50)-HMS为催化剂,反应时间4 h,苯甲醇转化率可达69.9%,苯甲醛选择性达到90.0%,催化剂在重复使用3次后活性基本不变。     

Dawson结构磷钨酸银催化绿色合成己二酸

以自制新型Dawson结构磷钨酸银(Ag3H3P2W18O62·n H2O)为催化剂,催化30%H2O2氧化环己酮合成己二酸,并采用FT-IR、SEM对催化剂进行表征。考察了催化剂用量、30%H2O2用量、反应时间、反应温度及催化剂重复套用次数等因素对反应的影响。结果表明:自制磷钨酸银具有Dawson结构,并且在多次使用后仍保持Dawson结构不变。单个磷钨酸银呈"棒球状"(平均粒径200~300 nm)。优化合成条件为:w(催化剂)=6.4%(基于环己酮质量),n(环己酮):n(30%H2O2)=100∶400,反应温度100℃,反应时间5.0 h。在此条件下,己二酸收率为81.4%。该催化剂具有良好的重复使用性能,重复使用五次时己二酸收率基本不变,是合成己二酸的高效、经济、绿色催化剂。     

负载型铁基复合氧化物催化苯酚羟基化的研究

在温和条件下对铁基复合氧化物催化苯酚和过氧化氢的羟基化反应进行了研究.结果表明,活性组分、载体以及催化剂/苯酚(质量比)、过氧化氢/苯酚(摩尔比)、反应温度和反应时间等对苯酚羟基化反应具有重要影响.Fe-A催化剂的活性组分形成了α-Fe2O3和尖晶石结构;Fe-B催化剂活性组分以非晶态分布在催化剂上,高度弥散,具有更好的催化性能.溶剂的加入,有助于苯酚和过氧化氢的混合,水是理想的羟基化反应溶剂,可以实现苯酚和过氧化氢水溶液的互溶,有利于·OH的生成.以Fe-B作催化剂,水为溶剂,反应温度65℃,反应时间1h,催化剂/苯酚(质量比)=0.02,水/苯酚(体积比)=2.0,过氧化氢/苯酚(摩尔比)=0.3,苯酚转化率21.6%,苯二酚选择性86.5%.     

9,9-二(3-苯基-4-羟基苯基)芴的合成

9,9-二(3-苯基-4-羟基苯基)芴是以芴酮和联苯酚为原料在酸性催化剂存在下经缩合反应而制得的Cardo骨架结构的双酚类化合物。考察了物料配比、反应温度和时间对反应收率的影响,并经过正交实验,确定了反应的最佳工艺条件:反应温度120℃,反应时间为12 h,n(芴酮)∶n(联苯酚)=1∶10,产品收率为85%,纯度99.5%(HPLC面积归一化法)。产品结构经~1H-NMR表征。     

癸二酸二缩水甘油酯的合成

以癸二酸为原料,合成了癸二酸二缩水甘油酯(DGSE),其结构经1H NMR,MS和元素分析表征。优化反应条件为:癸二酸100 mmol,n(癸二酸)∶n(NaOH)∶n(环氧氯丙烷)=1∶2∶3,催化剂x(四乙基溴化铵)=0.5%,回流反应2 h。在优化反应条件下,DGSE的收率93.4%,纯度82.6%。     

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.     

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.     

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.     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.