离子液体存在下脂肪醛的环化三聚反应

Aliphatic aldehydes such as ethanal,propanal,n-butanal,isobutyraldehyde,n-valeraldehyde,isovaleraldehyde,n-hexanal and n-octanal were converted into the corresponding 2,4,6-trialkyl-1,3,5-trioxanes through cyclotrimer-ization in the presence of the ferric chloride based ionic liquids at room temperature without solvent in high selec-tivity.The effects of different ionic liquids,acidity of ionic liquids and temperature on cyclotrimerization were alsostudied.The results showed that the ferric chloride based ionic liquids(apparent molar fraction of FeCl_3(x(FeCl_3)=0.62))were a kind of efficient catalysts for the cyclotrimerization of aliphatic aldehyde which could be separatedconveniently from the reaction mixture and recycled without loss of catalytic activity.The conversion of isobu-tyraldehyde and the selectivity to 2,4,6-triisopropyl-1,3,5-trioxane were 91.1% and 99.8% respectively under opti-mum reaction condition(isobutyraldehyde 25.0 g,[Et_3NH]Cl/FeCl_3(x(FeCl_3)=0.62)1.0 g,25 ℃for 1 h).     

高效液相色谱法测定大鼠血浆中的原儿茶酸

建立了大鼠血浆中原儿茶酸含量测定的高效液相色谱方法。采用的色谱柱为DiamondsilTM C18 柱(150 mm×4.6 mm,5 μm);流动相为乙腈-水(体积比为9∶91,用H3PO4 调pH至2.5);流速1.2 mL/min;检测波长260 nm;内标为对羟基苯甲酸。原儿茶酸的线性范围为0.050~3.20 mg/L,线性相关系数为0.9978，最低定量限为0.050 mg/L,日内和日间测定的精密度（以相对标准偏差表示）均低于7.0%,准确度（以相对误差表示）为-1.4%～2.6%；在0.050,0.40,3.20 mg/L低、中、高3个添加浓度水平下，血浆样品的提取回收率分别为83.4%,87.3%,91.1%。该方法简便,灵敏,准确,适用于大鼠体内原儿茶酸的药物动力学研究。     

A simple and efficient one-pot synthesis of β-acetamido carbonyl compounds using sulfated zirconia as a heterogeneous recyclable catalyst

Sulfated zirconia has been employed as an efficient recyclable catalyst for the preparation of various β-acetamidoketones or esters at room temperature. The process involves the one-pot multicomponent reactions of aromatic aldehydes, enolizable ketones or β-ketoesters and acetonitrile in the presence of acetyl chloride.     

Iron‐Catalyzed Aerobic Oxidation of Aldehydes: Single Component Catalyst and Mechanistic Studies

An aerobic oxidation of aldehydes towards carboxylic acids in MeCN using 1 atm of pure oxygen or oxygen in air as the oxidant and a catalytic amount of single component catalyst, Fe(NO₃)₃ · 9H₂O, has been developed. Carboxylic acids with different synthetically useful functional groups were obtained at room temperature. Two mechanistic pathways have been proposed based on isotopic labeling, NMR monitoring, and control experiments. The practicality of this reaction has been demonstrated by conducting several 50 mmol‐scale reactions using pure oxygen or an air‐flow of ~30 mL/min.     

Transition-Metal-Free Reverse Reactivity of (2-Alkynyl)-Arylaldimines: Assembly of Functionalized Amino-Indinones

Transition-metal-free regioselective synthesis of functionalized amino-indenones by the reaction of ortho-alkynylaldehydes with a broad range of primary amines by intramolecular cyclization has been described. The designed reaction proceeds through KOH-mediated Prins-type cyclization and DMSO-promoted oxidation of the cyclopent-2-en-1-one system. The proposed mechanism and role of solvent were well supported by control experiments. For the first time, we have disclosed the reverse reactivity of (2-alkynyl)-arylaldimines in a super basic system.     

Synthesis of fused indolines by interrupted Fischer indolization in a microfluidic reactor

This study describes our development of a microfluidic reaction scheme for the synthesis of fused indoline ring systems found in several bioactive compounds. We have utilized a continuous-flow microfluidic reactor for the reaction of hydrazines with latent aldehydes through the interrupted Fischer indolization reaction to form fused indoline and azaindoline products. We have identified optimal conditions and evaluated the scope of this microfluidic reaction using various hydrazine and latent aldehyde surrogates. This green chemistry approach can be of general utility to rapidly produce indoline scaffolds and intermediates in a continuous manner.     

硅胶键合N-丙基二乙烯氨基磺酸作为可回收固体酸催化剂催化合成α-氨基腈(英文)

Silica-bonded N-propyl diethylenetriamine sulfamic acid (SBPDSA) is employed as a recyclable catalyst to synthesize α-aminonitriles. These syntheses involved one-pot condensation of an aldehyde, an amine, and trimethylsilyl cyanide under mild reaction conditions at room temperature. SBPDSA was recycled seven times in the condensation of benzaldehyde, aniline, and trimethylsilyl cyanide without reduction of its catalytic activity.     

The Reaction Activity of Aromatic Carbonyl Compounds with Diphenylphosphine Oxide Studied by 31P NMR

Abstract

A series of α-hydroxyphosphine oxides were prepared by the reactions of diphenylphosphine oxide and aromatic carbonyl compounds and characterized by ¹H NMR, ¹³C NMR, ³¹P NMR, FT-IR, ESI-MS, and HR-MS spectra. The reaction rates and experimental conditions of aromatic aldehydes and aromatic ketones were obviously different due to the activity of their carbonyls. The different substituents of the aromatic aldehydes affected the reaction rate too, and the quantitative reactivity of their substituent conformed to the Hammett equation. The results were confirmed by ³¹P NMR spectroscopy.     

An efficient one-pot multi-component synthesis of 3,4,5-substituted furan-2(5H)-ones catalyzed by tetra-n-butylammonium bisulfate

A facile one-pot synthesis of 3,4,5-substituted furan-2(5H)-one derivatives from a three-component reaction of aniline derivatives, dialkylacetylenedicarboxylates and aromatic aldehydes under mild conditions using tetra-n-butylammonium bisulfate as a catalyst has been developed.     

An efficient green procedure for the synthesis of chalcones using C-200 as solid support under grinding conditions

Abstract

A simple, rapid, efficient and environmentally benign procedure for the synthesis of chalcones has been achieved by grinding aryl aldehydes and acetophenones with anhydrous barium hydroxide (C-200) in the absence of any solvent. The use of organic solvent for extraction of compound is also avoided. This present method is highly useful for the synthesis of 2′-hydroxy chalcones, required intermediates for the synthesis of flavanoids.