An Efficient Synthesis of Spiro‐oxindole Derivatives by Three‐Component Reactions in Water

An efficient synthesis of (3S)‐1,1′,2,2′,3′,4′,6′,7′‐octahydro‐9′‐nitro‐2,6′‐dioxospiro[3H‐indole‐3,8′‐[8H]pyrido[1,2‐a]pyrimidine]‐7′‐carbonitrile is achieved via a three‐component reaction of isatin, ethyl cyanoacetate, and 1,2,3,4,5,6‐hexahydro‐2‐(nitromethylidene)pyrimidine. The present method does not involve any hazardous organic solvents or catalysts. Also the synthesis of ethyl 6′‐amino‐1,1′,2,2′,3′,4′‐hexahydro‐9′‐nitro‐2‐oxospiro[3H‐indole‐3,8′‐[8H]pyrido[1,2‐a]pyrimidine]‐7′‐carboxylates in high yields, at reflux, using a catalytic amount of piperidine, is described. The structures were confirmed spectroscopically (IR, ¹H‐ and ¹³C‐NMR, and EI‐MS data) and by elemental analyses. A plausible mechanism for this reaction is proposed (Scheme 2).     

A New Mixed‐Valent Copper Cyanido Complex and a New Copper(II) Acetato Complex,Prepared with an Ionic Liquid

When copper(II) acetate is treated with the ionic liquid n‐butylmethylimidazolium cyanide (BMIm‐CN), in ethanol solution, two new copper coordination compounds are obtained. (BMIm)₂[Cu₄(CN)₇] comprises a 3D coordination polymer of cyanide bridged copper ions. This anionic coordination polymer contains Cu^I as well as Cu^II ions, i.e. it is a mixed‐valent compound. The polymer can be described as honeycomb structure with the BMIm⁺ cation being located in the cages. The second compound obtained from the chemical reaction is (BMIm)[Cu₂(OAc)₅][Cu(OAc)₂(H₂O)]₂ · C₂H₅OH, which can be described as double‐salt. The first unit (BMIm)[Cu₂(OAc)₅] contains paddle wheel copper(II) acetato moieties, which are bridged by additional acetato ligands and form infinite chains. The second part of the double salt is the neutral, [Cu(OAc)₂(H₂O)]₂ complex. These two parts as well as the co‐crystallized ethanol molecule are connected through a network of hydrogen bridges.     

Determination Limit of Fluorescence Turn‐On Probes for the Acetate Anion

Three fluorescent turn‐on probes containing 3,6‐dichloro‐9H‐carbazole as carbazyl part have been designed and synthesized. Among studied anions F^?, AcO^?, H₂PO , Cl^?, Br^? and I^?, AcO^? showed the strongest binding ability with all probes. The strong basic anions, such as AcO^?, H₂PO , and F^?, induced a significant red‐shift in absorption and a concomitant increase in fluorescent emission of the probes caused by photoinduced electron transfer (PET). The determination limit of probe 3 (Scheme 1) toward AcO^? is 3.0×10^?7 M . ¹H‐NMR Titration experiments shed light on the nature of the interaction between the probes and the anions. Theoretical investigation further illustrated the possible binding mode in these host? guest interactions and the roles of molecular frontier orbitals in molecular interplay.     

Catalytic reduction of 1- and 2-bromooctanes by a dinickel(I) Schiff base complex containing two salen units electrogenerated at carbon cathodes in dimethylformamide

A dinickel Schiff base complex (Ni₂(II)L) containing two salen units has been synthesized and characterized by NMR and mass spectrometry. The complex was used for the catalytic reduction of 1- and 2-bromooctanes and its electrochemical behavior, which is similar to that of nickel salen, was studied by cyclic voltammetry and controlled-potential electrolysis. Due to the proximity of the two nickel centers, the yield of octyl dimers is slightly higher for the electrochemical reduction of 2-bromooctane catalyzed by the dinickel complex than that by nickel salen. However, the yield of hexadecane does not increase for the catalytic reduction of 1-bromooctane, which can give more reactive primary radicals. In addition to the formation of various products, octylation of the dinickel complex takes place to a further extent for the reduction of 2-bromooctane than 1-bromooctane. Compared with nickel salen-catalyzed reduction, the electrochemical data also indicate that more octyl groups may incorporate into the dinickel complex. Mechanistically, the catalytic reduction of the bromooctanes involves the intermediacy of primary or secondary octyl radicals.     

Kristallstruktur von Caesiumacetat,Cs(CH3COO)

Crystal Structure of Cesium Acetate, Cs(CH₃COO) . The crystal structure of cesium acetate, Cs(CH₃COO), was determined from single crystal fourcirclediffractometer data: hexagonal crystal system, P6/m (No. 175), Z = 6, a = 1 488.0(2), c = 397.65(5) pm, V_m = 76.54(2) cm³/mol, R = 0.045, R_w = 0.030. The structure consists of flat layers of acetate anions parallel (001) that are separated by layers of cesium cations. There is a close relationship with the CaF₂ type according to CsO₂(CCH₃): each cesium cation has eight oxygen atoms as nearest neighbours. They form a heavily distorted cube with trapezoidal basal faces. In contrast to CaF₂, these polyhedra are linked via three faces and two edges to a three-dimensional network.     

An Extended Dienylium Terminus to Nucleophilic Addition with Tricarbonyl [3-(1-5-η-4-Isopropoxycyclohexa-2, 4-Dienyl) Ethyl Acetate] Iron Hexafluorophosphate

A study of the regioselectivity in nucleophilic addition to tricarbonyl (dienylium) iron complexes having an acetoxyethyl group (or methoxyethyl group) is reported. Reaction of the acetoxyethyl dienylium complex with the potassium salt of methyl 2-oxocylopentanecarboxylate was found to give a new product and a mechanism is proposed. The regioselectivity to nucleophilic addition was shown to be dependent on the use of an alcohol protecting group as in tricarbonyl (dienylium) iron complexes (5) and (15).     

兰索拉唑中有机溶剂残留量的测定

文章建立了采用直接进样毛细管气相色谱法测定兰索拉唑中甲醇、乙醇、乙酸乙酯残留量的方法.色谱柱为HP-FFAP石英毛细管柱,采用程序升温,载气为氮气,检测器为FID,以二氧六环为溶剂.在上述色谱条件下,甲醇的线性范围为6-54mg/L,乙醇和乙酸乙酯的线性范围为10-90mg/L;平均加样回收率分别为99.36、101.26%和101.57%.本方法简便、专属性强、准确度高,可用于测定原料药中甲醇、乙醇、乙酸乙酯的残留量.     

CIR技术红外光谱法应用研究

本文描述了通过使用CIR装置技术，实现了水溶液红外光谱分析。由三氮唑核苷、苯甲酸钠、乙酸钠等水溶液进行红外光谱分析研究，得到各自水溶液直接测定的红外光谱，并进行了定量分析研究，效果良好，说明了CIR技术具有较好的实用价值。     

Asymmetric total synthesis of (+)-gabosine C and (+)-4-epi-gabosine J using acetate migration and RCM reaction

A concise, unified and stereoselective total synthesis of (+)-gabosine C and (+)-4-epi-gabosine J from a common polyhydroxylated cyclohexenol intermediate which was synthesized from readily available D-ribose has been described. The synthetic avenue includes stereoselective Grignard reaction, silyl ether deprotection followed by acetate migration, RCM reaction, oxidative diol cleavage, hydroxymethylation and oxidative rearrangement as key steps.     

An anthracene based bispyridinium amide receptor for selective sensing of anions

A new receptor has been designed and synthesized for selective recognition of anions through hydrogen bonding and electrostatic interactions. The recognition ability has been studied by fluorescence, UV-vis and ¹H NMR spectroscopic methods. The results demonstrate that the receptor exhibits good recognition ability towards anions and shows strong binding to AcO⁻, and F⁻.