新试剂3,5—二溴—4—偶氮8—羟基喹啉苯基荧光酮光度法测定微量铝

在溴化十六烷基三甲胺（ＣＴＭＡＢ）存在下，ＰＨ６，０的ＨＡｃ－ＮａＡｃ缓冲介质中，铝与新试剂３，５－二溴－４－偶氮８－羟基喹啉苯基荧光酮形成红色三元胶束配合物，最大吸收波长位于５６４ｎｍ，表观摩尔吸光系数ε为１．３５×１０＾５．ｍｏｌ＾－１．ｃｍ＾－１，铝浓度在０～５μｇ／２５ｍＬ范围内符合比耳定律，拟定的方法用于铝铁黄铜中微量铝的测定，结果满意。     

Polyhydroxylated pyrrolizidines. Part 6: A new and concise stereoselective synthesis of (+)-casuarine and its 6,7-diepi isomer, from DMDP

A new synthesis for (+)-casuarine (1) and its 6,7-diepi isomer (15) in a stereocontrolled manner, is reported herein. An appropriately protected polyhydroxylated pyrrolidine, such as (2R,3R,4R,5R)-3,4-dibenzyloxy-2′-O-tert-butyldiphenylsilyl-2,5-bis(hydroxymethyl)pyrrolidine (3, protected DMDP), easily available from d-fructose, was chosen as the chiral starting material. Compounds 1 and 15 were obtained from 3, in seven steps, in a 23.2 and 20.5% overall yields, respectively.     

Preparation and characterization of slice-like Cu2(OH)3NO3 superhydrophobic structure on copper foil

Superhydrophobic structure was prepared on copper foil via a facile solution-immersion method. Thus slice-like Cu₂(OH)₃NO₃ crystal was prepared on the surface of the copper foil by sequential immersing in an aqueous solution of sodium hydroxide and cupric nitrate. And the superhydrophobic structure was obtained by modifying the slice-like Cu₂(OH)₃NO₃ crystal with 1H,1H,2H,2H-perfluorodecyltriethoxysilane (FAS-17). The morphologies, chemical compositions and states, and hydrophobicity of the surface-modifying films on the copper foil substrates were analyzed by means of scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and water contact angle measurement. Moreover, the thermal stability of the slice-like structure was also evaluated using thermogravimetric analysis (TGA). It was found that roughening of the copper foil surface helped to increase the hydrophobicity to some extent, but no superhydrophobicity was obtained unless the slice-like Cu₂(OH)₃NO₃ crystal formed on the Cu substrate was modified with 1H,1H,2H,2H-perfluorodecyltriethoxysilane. Besides, the superhydrophobicity of the FAS-17-modified slice-like Cu₂(OH)₃NO₃ structure was closely related to the surface morphology. And this hydrophobic structure retained good superhydrophobic stability at elevated temperature and in long-term storage as well, which should be critical to the application of Cu-matrix materials in engineering.     

Photooxygenation of Furylalkylamines: Easy Access to Pyrrolizidine and Indolizidine Scaffolds

A highly adaptable method targeting the ubiquitous and very important pyrrolizidine and indolizidine scaffolds is presented. The general synthetic utility of the method is underscored by its application to the rapid and easy synthesis of five natural products starting from readily accessible alkylfuran precursors. These unprotected primary furylalkylamines are subjected to photooxygenation conditions, which initiate a complex cascade reaction sequence concluding with the production of high value motifs. This sequence can be tailored to need by varying the choice of both photosensitizer and base additive.     

A facile one-pot three-component synthesis of ferrocene-grafted dispiro pyrrolidine/pyrrolizidine scaffolds through intermolecular [3+2] cycloaddition reaction of ferrocenyl Baylis-Hillman adduct

A one-pot synthesis of ferrocene-grafted dispiropyrrolidine/pyrrolizidine scaffolds has been accomplished in good yields through a facile 1,3-dipolar cycloaddition of various azomethine ylides derived from diketones and secondary amino acids with Baylis-Hillman adduct derived from ferrocene carbaldehyde. The regiochemical and stereochemical outcomes of the cycloaddition reaction were ascertained by X-ray crystallographic studies of one of the cycloadducts.     

Cis-trans-conversion of the bicycle in pyrrolizidines: The effect of the preferred conformations on the properties of the bases and the thermodynamics of conformational transformation of the ring fusion type. (Review)

The cis-trans conversion in pyrrolizidines and the deciding effect of steric factors on their conformational equilibrium are discussed. Work on the synthesis and characteristics of sterically strained pyrrolizidines is analyzed and discussed. It is shown that such compounds (predominantly trans-fused) have a series of features in their properties that greatly distinguish them from unstrained pyrrolizidines. The first results from study of the thermodynamics of cis-trans conversion of the pyrrolizidine bicycle are summarized. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1466, October, 2006.     

Synthesis of Pyrrolidines and Pyrrolizidines with α‐Pseudoquaternary Centers by Copper‐Catalyzed Condensation of α‐Diazodicarbonyl Compounds and Aryl γ‐Lactams

N‐aryl γ‐lactams react intermolecularly with acceptor–acceptor diazo reagents, usually dicarbonyl compounds, in a copper‐catalyzed process to yield functionalized pyrrolidines with α‐pseudoquaternary centers. As 1,2‐acyl or ‐phosphoryl migration is preferred, single regioisomers are obtained. Furthermore, in the presence of a Lewis acid, subsequent Friedel–Crafts reactions yield tricyclic pyrrolizidines in excellent yields (90–96 %) and diastereoselectivities (up to >20:1).     

Highly Enantioselective Intramolecular 1,3‐Dipolar Cycloaddition: A Route to Piperidino‐Pyrrolizidines

Enantioselective catalytic intermolecular 1,3‐dipolar cycloadditions are powerful methods for the synthesis of heterocycles. In contrast, intramolecular enantioselective 1,3‐dipolar cycloadditions are virtually unexplored. A highly enantioselective synthesis of natural‐product‐inspired pyrrolidino‐piperidines by means of an intramolecular 1,3‐dipolar cycloaddition with azomethine ylides is now reported. The method has a wide scope and yields the desired cycloadducts with four tertiary stereogenic centers with up to 99 % ee. Combining the enantioselective catalytic intramolecular 1,3‐dipolar cycloaddition with a subsequent diastereoselective intermolecular 1,3‐dipolar cycloaddition yielded complex piperidino‐pyrrolizidines with very high stereoselectivity in a one‐pot tandem reaction.     

Synthesis and glycosidase inhibition of C-7 modified casuarine derivatives

A series of C-7 modified analogues of casuarine have been synthesized from sugar-derived nitrone and assayed against various glycosidases. Introduction of C-7 aminomethyl or amide group led to sharp decrease of the inhibitory activities.     

邻硝基苯基荧光酮-钛-吐温-40体系分光光度研究及硅铁合金中钛的测定

系统研究邻硝基苯基荧光酮与钛的显色反应，试验多种表面活性剂对体系的作用及相应的光度性质，从而确定Ti(Ⅳ）－ONPF－Tween－40为较佳体系，在0.084-0.15mol/L HCl介质中形成紫红色配合物，其波长在530nm处的表观摩尔吸光系数ε为1.79×10^5L·mol^-1·cm^-1，配合物组成中Ti:ONPF＝1：4，钛浓度在0－1.2μg/10mL范围内服从比耳定律。应用于直接测定硅铁合金中钛，结果满意。