Total Synthesis of Several 8, 8",-Biflavones

8,8"-Biflavonoidsareantw0rtantclass0fbiflavonoids.Asasystematicresearchofthe8,8"-biflav0noids,wehavepreviouslyreportedthestudyonthereactionof2'-hydroxychaloneswithl2-H2SO4-DMSOsystem.'InthispaPer,thesynthesisof5,5",7,7',-tetTameth0xy-8,8"-biflavonela2,4,4",7,7"-tetramethoxy-8,8"-biflavone1b',4',4",,5,5,',7,7"-hexamethoxy-8,8"-biflav0ne1c4and4,4"-dibenZyl0xy-5,5",7,7"-tetramothoxy-8,8"-biflavoneldisreported.ThesyntheticmethodisshownintheSchemebelow.2-Hydroxyacet0phenonescondensedwithsubsti…     

8-Oxychinolin, 8-OxycMnaldin und 8-OxycMnolin-5-sultons?ure lassen sich

Ohne Zusammenfassung     

Aromaticity, optical properties and zero field splitting of homo- and hetero-bimetallic (C8H8)M(μ2-,η8═C8H8)M(C8H8) where M = Ti, Zr, Th Complexes

This work presents a relativistic calculation of electron delocalization, optical properties, and zero field splitting in a group of molecules with the structure (C(8)H(8))M(μ(2)-,η(8)═C(8)H(8))M(C(8)H(8)), where M = Ti, Zr and Th. Additionally we also studied the heterobimetallic combinations (Ti-Th and Zr-Th). The molecular properties are discussed based on their electronic structure and the influence of the electron mobility in metal-metal communication. Nucleus independent chemical shift (NICS) was determined via the gauge-including-atomic-orbital (GIAO) method with the OPBE functional. The time-dependent density functional theory (TDDFT) was employed to calculate excitation energies, and the electronic transitions over 500 nm are presented with the objective to analyze the transition metal role as an antenna effect in the absorption band in the near-IR region. Finally the ZFS was calculated using Pederson-Khana and coupled perturbed DFT approaches implemented in the ORCA code. The contributions to spin-spin coupling (SS) and spin-orbit coupling (SOC) were analyzed, and the spin-density over the metal centers is discussed employing our scheme of metal-metal communication. Our aim is to determine the influence of the electronic structure over the optical and magnetic properties in a group of model compounds to understand the transition metals effect over these properties.     

8',8"-去甲基三白脂素-8的全合成

以2-甲氧基酚,丁二酰氯和L-乳酸乙酯为起始原料,用会聚法完成了8',8"-去甲基三白脂素-8的全合成,总产率1.79%.其结构经1H NMR和MS表征.     

THE REARRANGEMENT OF 1,7β-DIMETHYL-7α-HYDROXY-8aα-CARBOXYMETHYL-9β-CARBOMETHOXY-4bα, 5, 6, 7, 8, 8a-HEXAttYDROFLUORENE LACTONE INDUCED BY DIBAL-H

1,7β- Dimethyl-7α- hydroxy-8aα-carboxymethyl-9β-carbomethoxy-4bα, 5, 6, 7, 8, 8α-hexahydrofluorene lactone(2) is converted to 8, 12-epoxyallogibberic acid methyl ester(4) by the action of diisobutyl aluminum hydride (DIBAL-H) with a novel rearrangement reaction.     

Synthesis of the Analogs of Triptolide： 7, 8-Deoxytriptolide, 7 α, 8α-Epoxytriptolide and Related Ketones

Two novel analogues of triptolide were synthesized using triptolide as the starting material through reductive opening of epoxy ring, hydration and olefin epoxidation, and related ketones have also been afforded by oxidation of them with IBX or Jone‘s reagent.     

Synthesis, Structure, and Properties of the Cyclic Mixed Valence Oxothiotungstate [W8S8O8(OH)8(H3WO6]2−

The novel polyoxothioanion [W₈S₈O₈(OH)₈(H₃WO₆]^2– was prepared by acido-basic condensation of four [W₂S₂O₂]²⁺ thiofragments in the presence of tungstate ion. Rb₃[W₈S₈O₈(OH)₈(H₃WO₆]13H₂O was isolated in the solid state and fully characterized by X-ray diffraction study (monoclinic, C2/m [a=20.3540(1) Å; b=11.8042(2) Å; c=13.9355(2) Å; =90°; =131.134(1)°; =90°]. The molecular structure consists of an octameric {W₈S₈O₈(OH)₈} wheel encapsulating a central octahedron {H₃WO₆}^3–. The packing reveals a remarkable 3-D array resulting from connections between Rb⁺ and octameric wheels. The Rb⁺ cations form infinite parallel chains, which are mutually connected by the cyclic oxothioanions. The compound was also characterized by infrared spectroscopy and elemental analysis.     

Structure of 7, 8, 17, 18-Tetrabromo-5,10,15, 20-Tetraphenylporphinatozinc(Ⅱ)

1mrnODUCTIONRecentlywereportedthestructureof7,8,17,18--tetrabromo--5,10,15,20--tetraphenylporphinatozinc(H,TPPBr.)ill.Inordertoobservetheeffectofthefoulelectron--withdrawingbromogroupsonthestructureofametalcomplexofthisPOrphyrin,thetitlecompoundwaspreparedbyanestablishedmethod[Ziandthecrysta:wasobtained,whichissuitableforstructureanalysisbylayeringasolutioninCHCI,withpetroleum(60--90C)--piperidine.2EXPERIMENTALThetitlecomplexwassynthesizedbyreactionofH,TPPBr.andZn(CH,COO):.ZH…     

Synthesis of driman-8α,11-diol from sclareol through 8α,12-epoxy-14,15-bisnorlabdan-13-one

A four-step synthesis of driman-8,11-diol from sclareol in 44% total yield is described that includes the intermediates (12R)-8,12-epoxy-14,15-bisnorlabdan-13-one, (12S)-8,12-epoxy-12-acetoxy-13,14,15,16-tetranorlabdane and 8,12-epoxy-13,14,15,16-tetranorlabd-11-ene.Institute of Chemistry, Academy of Sciences of the Republic of Moldova, Kishinev, fax (3732) 73 97 75, Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 124–125, March–April, 2000.     

RECl_2·nTHF(RE=Nd,Sm,Yb)与C_8H_8的反应

近年来低价稀土有机化学领域的研究工作相当活跃,相继发现Sm~(2+)、Yb~(2+)化合物不仅可催化烯烃氢化、聚合’,而且还可以和CO、苯乙炔等化合物发生氧化加成反应.但文献所报道的工作主要局限于Sm~(2+)、Eu~(2+)和Yb~(2+)化合物.我们首次研究了NdCl_2·nTHF的化学反应性能,并发现这一配合物具有很强的还原性,甚至可以直接和CpH,CH_3CpH等反应.最近我们发现NdCl_2·nTHF可以在室温直接与C_8H_8反应,产物为[C_8H_8NdCl·2THF]_2和NdCl_3;SmCl_2·nTHF也可以在室温和C_8H_8反应,反应产物为[C_8H_8 SmCl·     

面包酵母对1, 4, 4α, 8α-四氢-1, 4-亚甲基萘-5, 8-二酮的催化异构化

文章描述了面包酵母将1, 4, 4α, 8α-四氢-1, 4-亚甲基萘-5, 8-二酮催化异构化为1, 4-二氢-5, 8-二羟基-1, 4-亚甲基萘, 而不是还原为相应的羟基化合物。     

过渡金属（Ti,Zr,Mn,Cu,Mo,Cr,Co）离子掺杂的MCM—48的合成,表…

合成了掺杂Ｔｉ、Ｚｒ、Ｍｎ、Ｃｕ、Ｍｏ、Ｃｒ和Ｃｏ过渡金属离子的中介孔分子筛ＣＭＣ－４８。通过ＴＥＭ、孔分布测试、ＸＲＤ、电子能谱、红外吸收及热失重分析对掺杂的ＭＣＭ－４８进行结构表征,并研究了其催化性能。     

光学纯的(4S, 8R)-和(4S, 8S)-1- 烯-8, 9-二醇的改进合成法

本文提出了一个改进的合成两个光学异构纯的94S)-1- 烯-8, 9-二醇的方法,其优点是简便、有效, 适于克量级制备。     

光学纯的(4S, 8R)-和(4S, 8S)-1- 烯-8, 9-二醇的改进合成法

本文提出了一个改进的合成两个光学异构纯的94S)-1- 烯-8, 9-二醇的方法,其优点是简便、有效, 适于克量级制备。     

Composition,structure, and functional properties of organomineral composite sorbents KU-2×8-ZnS and KU-2×8-PbS

Organomineral composite sorbents KU-2×8-ZnS and KU-2×8-PbS were synthesized on the basis of the matrix of a strongly acidic KU-2×8 cation exchanger. Scanning electron microscopy and elemental analysis were used to study their microstructure and chemical composition. With the use of potentiometric titration, their bifunctional nature was revealed and the dissociation constants and the total exchange capacities of the ionogenic groups were determined. The sorption of copper(II), zinc, and cadmium by KU-2×8-ZnS and KU-2×8-PbS sorbents from 0.005 M solutions of their salts was examined. The total dynamic sorption capacity of the composite sorbents for the above metals, found in the study, exceeds similar values for the individual KU-2×8 cation exchanger by a factor of 1.6–2.0 and that in 0.001–0.050 M solutions of potassium and calcium chlorides, by a factor of 1.3–4.5. An explanation is suggested for the sorption process of heavy nonferrous metals on composite sorbents with an active sulfide component by the mechanism of coordination copolymerization.     

RECl2·nTHF(RE=Nd,Sm,Yb)与C8H8的反应

近年来低价稀土有机化学领域的研究工作相当活跃,相继发现Sm²⁺、Yb²⁺化合物不仅可催化烯烃氢化、聚合^[1],而且还可以和CO、苯乙炔等化合物发生氧化加成反应^[2].但文献所报道的工作主要局限于Sm²⁺、Eu²⁺和Yb²⁺化合物.     

中国科学院新当选院士简介(1999年,化学部,8人)

陈凯先（ＣｈｅｎＫａｉｘｉａｎ）男,汉族,药物化学家,中国科学院上海药物研究所研究员。１９４５年出生于重庆市。１９６７年毕业于复旦大学化学系。１９８２年和１９８５年在中国科学院上海药物研究所先后获硕士和博士学位。１９８５年至１９８８年在法国生物物理化学研究所做博士后研究。现任中国科学院上海药物研究所所长。陈凯先主要从事计算机辅助药物分子设计,进行有机小分子和生物大分子的结构与生物活性之间关系的理论计算、有活性的有机小分子结构预测和设计,他提出了计算药物和受体疏水作用力场三维分布的数学模型和药物分…