Fe-MIL-101催化Paal-Knorr反应合成吡咯衍生物

以Fe-MIL-101为非均相催化剂,通过多种伯胺与2,5-二甲氧基四氢呋喃进行Paal-Knorr反应,高效合成相应的吡咯衍生物.在Fe-MIL-101结构中,裸露的Fe(Ⅲ)配位点作为催化活性中心参与吡咯衍生物的催化合成反应.同时Fe-MIL-101的高比表面积和大的孔尺寸确保了底物分子与催化活性中心的充分接触以及产物的自由脱离,从而促进了催化反应的快速进行.Fe-MIL-101在催化反应过程中具有很好的稳定性,多次循环使用后仍能表现出良好的催化性能.此外,该催化剂在伯胺(包括脂肪胺、芳香胺)与2,5-己二酮的Paal-Knorr缩合反应中也具有优异的催化性能.     

A straightforward highly efficient Paal-Knorr synthesis of pyrroles

A straightforward simple synthesis of substituted pyrroles using bismuth nitrate-catalyzed modified Paal-Knorr method has been accomplished with an excellent yield. This method produces pyrroles with multicyclic aromatic amines.     

An approach to the Paal-Knorr pyrroles synthesis catalyzed by Sc(OTf)3 under solvent-free conditions

A facile synthesis of N-substituted pyrroles by the Paal-Knorr condensation has been accomplished using a simple procedure. Among different metal triflates screened, 1 mol % Sc(OTf)₃ efficiently promoted the reaction to give excellent yield (89-98%) under mild reaction conditions. Additionally, Sc(OTf)₃ could be recovered easily after the reactions and reused without evident loss in activity.     

New potent cytotoxic lamellarin alkaloids from Indian ascidian Didemnum obscurum

Chemical investigations of the ascidian Didemnum obscurum has resulted in the isolation of four new lamellarin alkaloids, lamellarin-ζ (1), lamellarin-η (2), lamellarin-? (3) and lamellarin-χ (4) along with seven known lamellarins, lamellarin-K (5), lamellarin-I (6), lamellarin-J (7), lamellarin-K triacetate (8), lamellarin-L triacetate (9), lamellarin-F (10) and lamellarin-T diacetate (11). The structures of the compounds 1-11 were established by detailed analysis of NMR spectral data. Cytotoxic activity of the isolates has been done against coloractal cancer cells.     

An approach to the Paal–Knorr pyrroles synthesis in the presence of β-cyclodextrin in aqueous media

An efficient and facile method for the synthesis of N-substituted pyrroles in moderate to good yields by the Paal–Knorr reaction of γ-diketones with amines in the presence of β-cyclodextrin in aqueous media has been developed.Moreover,this process tolerated diamines(e.g.,para-,meta- or orthophenylenediamine)to construct bis-pyrrole or mono-pyrrole derivates.β-Cyclodextrin can be recovered easily after the reactions and reused without evident loss in activity.     

利用Paal-Knorr反应在无催化剂和溶剂条件下合成吡咯衍生物

Paal-Knorr合成法是一个常见的吡咯合成方法。本文报道了无需使用任何催化剂和溶剂,在室温条件下多种胺(包括脂肪胺、芳香胺)和2,5-己二酮发生Paal-Knorr缩合反应,且合成的吡咯衍生物产率较高。这种合成方法具有反应条件温和、实验操作步骤简单以及产物容易分离等优点,具有一定的实用价值。     

甲酸催化的室温无溶剂条件下利用Paal-Knorr反应合成吡咯衍生物的方法

以甲酸为催化剂, 无需使用任何溶剂, 在室温条件下, 多种伯胺(包括脂肪胺、芳香胺)与2,5-己二酮发生Paal-Knorr缩合反应, 生成相应的吡咯衍生物. 该方法反应条件温和、操作简便、反应时间比较短、产物易于分离、收率高、环境友好.     

Pyrrole synthesis in ionic liquids by Paal-Knorr condensation under mild conditions

Paal-Knorr condensation of 2,5-hexandione with primary amines was successfully carried out in ionic liquids. Through investigating different ionic liquids, different reaction times, the reaction, using ionic liquids as solvent, exhibited simple product isolation procedure, improved yields and exclusive selectivity and the mild conditions and the avoidance of using toxic catalysts are also its special features. Recovery and reuse of ionic liquid are also satisfactory.     

Synthesis of puleganic amides via a catalytically efficient two-step approach

Puleganic amides display interesting insect-repellent properties. A new synthetic route to this type of amide was developed involving an organocatalytic cyclization and metal-catalyzed hydrogenation in a one-pot protocol. An eco-friendly oxidative amination provided the puleganic amides with only one purification step and acceptable yields.     

Asymmetric synthesis of trans-3,4-dialkyl-gamma-butyrolactones via an acyl-Claisen and iodolactonization route

[reaction: see text] A new, efficient, and general asymmetric synthesis of enantiomerically pure trans-3,4-dialkyl-gamma-lactones has been developed. The key steps are (1) copper-catalyzed three-component coupling of chiral amine, aldehyde, and alkyne, (2) acyl-Claisen rearrangement, and (3) iodolactonization. The products, chiral gamma-lactones, are versatile synthetic intermediates and structural units of natural products and modified nucleosides.     

Synthesis of new 2,5-dimethyl pyrrole derivatives from acetonylacetone

<正>Acetonylacetone 1 was treated with thiourea,aniline,glycine and glutamic acid to give pyrrole derivatives 2,3,5,and 9 by Paal-Knorr reaction,respectively.Then 3 was successfully transformed into the related pyrrole derivative 4 by Mannich reaction. Compounds 6,7 and 8 were obtained by reacting 5 with phenethyl alcohol,phenylallylic alcohol and leaf alcohol by esterification reactions,respectively.The structures of all new products were elucidated by IR,NMR and HRMS spectra.     

A facile route to the pentacyclic lamellarin skeleton via Grob reaction between 3-nitro-2-(trifluoromethyl)-2H-chromenes and 1,3,3-trimethyl-3,4-dihydroisoquinolines

The basic structural framework of lamellarin alkaloids, 8,9-dihydro-6H-chromeno[4′,3′:4,5]pyrrolo[2,1-a]isoquinoline derivatives, has been obtained in good yields via Grob reaction between 3-nitro-2-(trifluoromethyl)-2H-chromenes and 1,3,3-trimethyl-3,4-dihydroisoquinolines in refluxing isobutanol. When the reaction was carried out in toluene at room temperature, only Michael adducts, as a mixture of two diastereomers, were isolated.     

Synthesis and antimicrobial,antiproliferative and anti-inflammatory activities of novel 1,3,5-substituted pyrazoline sulphonamides

The design of novel molecules is imperative for the discovery of potent drugs in the medicinal chemistry field. In this work, new 1,3,5-substituted pyrazoline sulphonamides were synthesised using a two-step process with microwave assistance and evaluated biologically for their antimicrobial, antiproliferative, and anti-inflammatory properties. Most of the sulphonamides bearing 3-OH or 4-Cl groups exhibited significant inhibition of two Gram-positive bacteria, Bacillus subtillis and Staphylococcus aureus, and the yeast Candida albicans. Six compounds showed good activity against the cancer cell lines cervix carcinoma (Hep-2C) and human lung carcinoma (A549) with IC₅₀ in the range 16.03 ± 1.63 to 22.75 ± 0.19 μM and 18.64 ± 1.02 to 20.66 ± 2.09 μM, respectively, and exhibited low toxicity against mammalian Vero cells. In evaluating in vitro anti-inflammatory behaviour, five compounds showed high inhibition of NO production over the standard reference, with low toxicity against murine macrophage cell line RAW 264.7. Further investigation found that two compounds, 1b and 18b, exhibited the highest activity when testing mouse ear oedema. The findings are promising for the discovery of potent new drugs.     

Synthesis of nucleoside alpha-thiotriphosphates via an oxathiaphospholane approach

[reaction: see text]. Nucleoside 5'-O-(alpha-thiotriphosphates) were obtained in reactions of the appropriate nucleoside 5'-O-(2-thio-1,3,2-oxathiaphospholanes) with pyrophosphate in the presence of DBU. The presented method allows also for preparation of alpha-seleno congeners and corresponding alpha-modified diphosphates.     

Synthesis of 2,3-syn-diarylpent-4-enamides via acyl-Claisen rearrangements of substituted cinnamyl morpholines: application to the synthesis of magnosalicin

The acyl-Claisen rearrangement of substituted phenylacetyl chlorides and cinnamyl morpholines gives 2,3-syn-diarylpent-4-enamides. Electron-rich cinnamyl morpholines containing alkoxy substituents only reacted with phenylacetyl chlorides; replacement of the phenylacetyl chlorides with alkyl acid chlorides in these reactions gave no rearranged products. Use of the morpholine amides generated in the synthesis of the natural tetrahydrofuran neolignan magnosalicin and tetraphenyl tetrahydrofuran is also reported.     

Synthesis and antiproliferative evaluation of glucosylated pyrazole analogs of K252c

Pyrazole analogs of the staurosporine aglycon K252c were recently described as potent inhibitors of the three Pim protein kinase isoforms. To evaluate the impact of the introduction of a sugar moiety on the biological activities of this heterocyclic scaffold, four new glucosylated pyrazole analogs of K252c were synthesized. Their biological evaluation demonstrated that most active compounds 11 and 19 substituted by a β-d-glucosyl moiety at N12 or N13 positions exhibited antiproliferative activities toward HCT116 cells.     

Synthesis of N-substituted imides via solid-liquid phase-transfer catalytic reaction

Summary N-substituted imides (RSIs) were synthesized from the reactions of alkylbromides (RX) and potassium salts of imides (KSIs) under solid-liquid phase-transfer catalytic conditions (SL-PTC). No water is required in the reaction system. In this work, serious hydration of KSIs is avoided using SL-PTC to synthesize RSIs. The reaction catalyzed by quaternary ammonium salts is greatly enhanced in the solid-liquid solution     

Synthesis of cyclophanes via an intermolecular Pd-catalyzed enyne-diyne cross-benzannulation approach

Several novel types of cyclophanes were efficiently synthesized via an intermolecular palladium-catalyzed cross-benzannulation of cyclic enynes and diynes. These types of cyclophanes are not accessible through an intramolecular mode of the homo-benzannulation protocol, reported previously. Cyclic reactants (enynes and diynes) were readily prepared in reasonable yields from commercially available materials using known procedures. The fact that the cyclic Z-enyne 29, in contrast to its E-counterpart, underwent benzannulation to produce the cyclophane 28 brought additional support for the necessity of having an E-hydrogen atom at the terminal olefin moiety of nonactivated enynes, which was found previously in the benzannulation of the acyclic substrates.     

仙茅素A的全合成

首次报道了仙茅素A[2,5-双(3,4-二羟基苯基)呋喃-3-甲醛]的全合成。以3,4-二甲氧基苯乙酮为起始原料,经Paal-Knorr反应,选择性溴代及还原等反应合成了仙茅素A,其结构经1H NMR,13C NMR和ESI-MS表征。     

Synthesis of antidepressant duloxetine via asymmetric transfer hydrogenation

Antidepressant duloxetine （1） was prepared via asymmetric transfer hydrogenation of 3-（dimethylamino）-1-（thiophen-2- yl）propan-1-one （3）. The Ru（Ⅱ）, Rh（Ⅲ） and Ir（Ⅲ） complexes of several chiral ligands were examined as the catalyst and （S,S）-N-tosyl-1,2-diphenyl ethylenediamine （TsDPEN）-Ru（Ⅱ） complex was found to provide good yield and excellent enantioselectivity. 2007 Ming Yan. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.