锚链固定的多相化铑膦配合物氢甲酰化反应催化剂的制备及其催化性能

以溶胶-凝胶与锚链固定相结合的方法制备了新型多相化羰基铑膦配合物催化剂.利用FT-IR,XPS和ICP对催化剂进行了表征.考察了该催化剂对1-己烯氢甲酰化反应的催化性能,得到较佳的反应条件,即反应温度100℃、反应时间12h、催化剂用量为0.3382g(相当于金属铑含量为4.4×10-5mol)、反应压力5.0MPa.此时1-己烯的转化率为98.5%、醛的选择性92.4%、n/i比1.43.该催化剂循环使用7次仍具有较高的催化活性和选择性,表明该催化剂具有好的循环使用性能.XPS、ICP分析证明铑的部分流失主要是由于氢甲酰化反条件下CO取代膦配体所致.     

C60-TEGs/PdCl2催化Suzuki反应绿色合成沙坦联苯

采用环境友好的水溶性富勒烯负载PdCl_2纳米催化剂[C_(60)-TEG_S/PdCl_2]催化邻溴苯腈和对甲基苯硼酸合成沙坦联苯(2-氰基-4′-甲基联苯)。该反应选用绿色溶剂水为反应溶剂,并分别考察了催化剂用量、反应温度、反应时间、碱的种类以及碱量对收率的影响。催化剂量为0.01 mol%,以2 mmol K_2CO_3作为碱,室温纯水中反应4 h产率能够达到93.6%。催化剂循环利用5次后,催化活性没有明显下降。     

水相研磨技术合成2-取代-2,3-二氢-4(1H)-喹唑啉酮(英文)

以2-氨基苯甲酰胺和醛或酮为原料,苯磺酸亚铁为催化剂,采用研磨技术在水相进行反应,高效合成了2,3-二氢-4(1H)-喹唑啉酮。产品结构通过IR,1H NMR,质谱和元素分析进行表征。提出了可能的催化作用机理。该方法具有产率高、操作和后处理过程简便、催化剂能循环使用等优点。     

固载化ZnCl2催化合成3-甲基-3-丁烯-1-醇

采用碾磨-活化法制备了SiO₂-ZnCl₂(Silzic)催化剂,并将其用于异丁烯与甲醛Prins缩合合成3-甲基-3-丁烯-1-醇(MBOH)。系统研究了温度、物料比、时间和催化剂的组成及用量对该反应的影响。结果表明,在不同的条件下,甲醛都保持着99%以上的高转化率;然而,不同的条件对MBOH的选择性和收率的影响程度不同,其中,反应温度、催化剂的酸量是影响该反应的关键因素;物料比和反应时间对MBOH的选择性和收率的影响相对较小。实验得到最佳的反应条件为,反应温度210 ℃、二氧六环8 g、三聚甲醛1.5 g、n(异丁烯)/n(三聚甲醛)=7:1、30 mg 1 mmol/g Silzic 和反应时间2 h,在此条件下MBOH的选择性和收率可分别达到93.8%和93.4%。当催化剂循环使用五次时,MBOH的收率降为85.2%,表明该催化剂具有一定的重复使用性。     

羟基磷灰石负载HRh(CO)(TPPTS)3催化1-己烯氢甲酰化反应高选择性和特殊的异构化功能

采用浸渍法制备了以羟基磷灰石(HAP)载型水溶性铑络合物HRh(CO)(TPPTS)3/HAP催化剂(TPPTS=三苯基膦三间磺酸钠), 采用傅里叶变换红外光谱(FTIR)、 固体核磁共振波谱(31P CP-MAS NMR)、 扫描电子显微镜(SEM)、 电感耦合等离子发射光谱(ICP-OES)和比表面积测定(BET)等对催化剂进行了表征. 该催化剂在催化1-己烯氢甲酰化反应中表现出高活性和高选择性, 在优化条件下获得了100%的醛选择性和高转化频率(TOF=2465 h-1). 该催化剂还对1-己烯、 2-己烯和3-己烯表现出特殊的异构化功能. 该催化剂制备方法简单, 通过简单离心分离可以循环使用. 对HAP负载HRh(CO)(TPPTS)3的原理以及催化剂对烯烃异构化的机理进行了探讨.     

活性炭固载吡啶亚胺钯粒子催化Heck反应的研究

采用硝酸对活性炭进行氧化处理,增加活性炭上羧基的含量,然后与乙二胺、吡啶-2-甲醛反应将吡啶亚胺配体引入活性炭,并以此为载体与氯化钯反应制得活性炭固载的吡啶亚胺钯粒子。采用傅里叶变换红外(FT-IR)光谱、X射线光电子能谱(XPS)和透射电镜(TEM)手段对其进行表征,并研究了该催化剂对Heck反应的催化性能。实验结果表明,催化剂中钯粒子通过配位键固定在载体上,在载体表面均匀分布,粒径在10nm左右。该催化剂对碘代芳烃和烯烃的Heck反应具有较高的催化活性,并具有良好的循环使用性能。     

乙烯焦油炭磺酸催化果糖脱水合成5-羟甲基糠醛

以蒸馏后的乙烯焦油重组分为原料,采用交联-磺化法制备了乙烯焦油炭磺酸。 利用红外光谱(FT-IR)、X射线衍射(XRD)、拉曼光谱(Raman)、热重分析(TGA-DTG)、扫描电子显微镜(SEM)等手段对该催化剂进行结构和性能表征。 结果表明,该催化剂呈现无定形石墨碳结构,且具有较高的酸量(4.20 mmol/g),表面的磺酸官能团是其关键活性中心。 并将该催化剂用于果糖脱水合成5-羟甲基糠醛(5-HMF)的反应,在130 ℃反应140 min,催化剂用量0.3 g、溶剂用量8 mL及助剂用量0.3 g的条件下,果糖转化率和5-HMF产率分别为96.2%和52.1%,分离得到的5-HMF纯度可达97.0%。催化剂循环使用5次后,果糖的转化率和5-HMF的产率分别保持在85.1%和40.8%以上。     

(1S,2S)-DPEN修饰的Ir/Al2O3催化苯乙酮及其衍生物的不对称加氢反应$

在碱性条件下制备了三氧化二铝负载的铱(Ir/γ-Al2O3)催化剂,并用于苯乙酮及其衍生物的不对称催化加氢反应.考察了不同的碱、碱浓度、手性二胺(1S,2S)-1,2-二苯基乙二胺[(1S,2S)-DPEN]浓度、反应温度和反应压力对催化剂及反应的影响.结果显示,在优化反应条件下,该催化剂表现出较高的催化活性和良好的对映选择性,其中异丁酰苯不对称催化加氢反应的对映选择性达到了80.3%.该催化剂不需要使用任何稳定剂,制备方法简单,催化性能稳定,通过简单的离心分离即可循环使用.     

无溶剂超声辐射下磷钨酸铈催化合成5-亚烃基-2,2-亚戊基-1,3-二噁烷-4,6-二酮

在CePW12O40催化下,芳香醛和2,2-亚戊基-1,3-二噁烷-4,6-二酮在无溶剂条件下经超声辐射合成了8种5-亚烃基-2,2-亚戊基-1,3-二噁烷-4,6-二酮.当催化剂的用量为5%(摩尔分数)时,室温反应20～35 min,收率为87.6%～94.1%.此外,还探讨了CePW12O40的可能催化机理.该方法具有条件温和,反应时间短且收率高的优点.催化剂CePW12O40对环境友好且可循环利用.     

无溶剂超声辐射下琥珀酸二酰亚胺磺酸铈催化合成5-[(3-吲哚基)-甲基]-2,2-二甲基-1,3-二噁烷-4,6-二酮衍生物

在琥珀酸二酰亚胺磺酸铈催化下,吲哚、醛和2,2-二甲基-1,3-二噁烷-4,6-二酮在无溶剂条件下超声辐射合成了10种5-[(3-吲哚基)-甲基]-2,2-二甲基-1,3-二噁烷-4,6-二酮衍生物.当催化剂的用量为3%(摩尔分数)时,30℃反应30~60 min,收率为68.9%~96.7%.此外,还探讨了琥珀酸二酰亚胺磺酸铈的催化机理.该方法具有条件温和,反应时间短且收率高的优点.催化剂邻琥珀酸二酰亚胺磺酸铈对环境友好且可循环利用.     

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.