简介：￣１ＨＡＮＤ￣（１３）ＣＮＭＲＳＴＵＤＹＯＦＩＮＣＬＵＳＩＯＮＣＯＭＰＬＥＸＡＴＩＯＮＯＦＤＳＳＷＩＴＨβ－ＣＹＣＬＯＤＥＸＴＲＩＮ￥ＱｉｎｇＸｉａｎｇＧＵＯ；ＴａｎＲＥＮ；ＺｉＺｈｏｎｇＬＩａｎｄＹｏｕＣｈｅｎｇＬＩＵ（ＮａｔｉｏｎａｌＬａｂｏｒａ...

简介：FournewtaxanediterpenoidswereisolatedfromthebarkofTaxusyunnanensis.Theirstructureswereelucidatedasthenewskeletonwith5/7/6/4memberedringsbyspectralanalysisand2DNMRshiftcorrelationexperiments.

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简介：Theabinitiomolecularorbitalmethodisemployedtostudytheenantioselectivereductionofacetophenonewithboranecatalyzedbythiszolidino[3,4-c]oxazaborolidine.Computationresultshowsthatthecontrollingstepforthereductionisthedecompositionofthecatalyst-alkoxyboraneadductandthereductionleadstoS-alcohols.ThetransitionatateofthehydridetransferfromtheboranemoietytothecarbonylcarbonofacetophenoneisatwistedchairstructurewithaB(2)-N(3)-BBH3-HBH3-CCo-OCO6-memberedring.

简介：ThevibrationalRamanspectrahavebeenobtainedforpurifiedsolidfilmsC60.Threebandswereobservedoutofthetotalof10thatweretheoreticallypredicted.Somephenomenawhichmaybeduetophoton-inducedoxidationinthevibrationalRamanmeasuringwereobserved.

简介：IntroductionInthepastseveralyears,muchresearchworkhasbeendoneforthesynthesisofC-fusedbicyclo-β-lactamcompoundsandaconcise“DoubleAnnulation”procedurehasbeendeveloped.Theβ-lactamringisformedbytheclassicalStaudingerreaction［1—3］betweenα-(alkylthio)acylchlorideandanequivalentα,β-unsaturatedimine.Thesulfurringissubsequentlyfusedontotheβ-lactamunitbymeansofahalogen-promotedheterocyclizationprocess［4—6］.ThisprocedurewasappliedtothesynthesisofpenemasillustratedinFig.1.TheobtainedX-penemsareakindofimportantintermediatesforsynthesizingaseriesofβ-lactamcompounds,forexample,theyarecarboxylatedbycouplingreactionsontheCatomwhichislinkedtohalagen,formingpenem［7］.Animportantpurposeintheresearchfieldistoprobeintonewβ-lactammedicines.

简介：为了推进，从抗菌剂fluoroquinolone(FQ)为移动扩展一条有效修改线路到antitumorFQ，标题混合物的二个系列基于有二的FQC3羧基的组的isostere熔化了杂环的戒指，[1,2,4]triazolo[3,4-b][1,3,4]thiadiazine和pyrazolo[5,1-c][1,2,4]分别地，triazole被设计并且综合了从当前的抗菌剂FQ开始，并且他们的在里面对L1210的vitroantitumor活动，CHO房间线经由他们的各自的IC被评估

简介：1IntroductionFullerenehasreceivedconsiderableattentionandagreatresearchinginterestduetoitsuniquestructureandinterestingproperties[1-3].Manyfunctionalgroupshavebeenintroduced,oftenregion-orstereo-selectively,fortuningthephysicalpropertiesofC60andforconstructingsupramoleculararchitectures[4-6].AmongallkindsofC60derivatives,thediseoticmolecule-substitutedC60derivativesshowinterestingproperties,especially,liquidcrystalproperties.Uptonow,fewC60derivativeswithdiscotic-moleculargroupsandtheirliquidcrystalpropertieshavebeenstudied.In1996,Deschenauxetal.[7]reportedthefirstmesomorphicC60-ferrocenederivative.Tianetal.[8]synthesizedaC60-perylenederivativein2004.Nakanishietal.[9]preparedaseriesofuncommonliquidC60derivativeswith2,4,6-tris(alkyloxy)benzalgroupsin2006.Lately,Geertsetal.[10]describedthesynthesisofmesogenicphthalocyanine-C60.

简介：ThreenovelC2-symmetricmacrocyclescontainingpyridylunitshavebeenpreparedbythecycliccondensationofchiraldiamideintermediateswith2,6-pyridinedicarbonyldichlorideinhighlydilutedsolutionatroomtemperature.

简介：Arylhalidesareakindofextremelyvaluablecompoundsusedintransition-metal-catalyzedcouplingreactions,aswellasimportantstructuremotifsinmanynaturalproductsandmanufactureddrugs[1,2].Theclassicalapproachforpreparationofhaloarenesiselectrophilicaromaticsubstitution(EAS)usingvarioushalogenatingreagentsoroxidativehalogenationswithhalogenatingreagentgeneratedinsitufromhalidesandoxidants,suchasperoxide,oxygenandmeta-cholorperoxybenzoicacid(mCPBA)[3,4].However,harshreactionconditionsarerequiredforhalogenationoflessactivearomatics.orthoMetalationfollowedbyhalogenquenchingisanotherapproachforhalogenationofaromatics[5].However,thereareobviousdrawbacksforthesemethods,suchaslowregioselectivity,harshconditionsandevendangerousprocedures.Therefore,thedevelopmentofanalternativeandpracticalwayremainschallengeinorganicsynthesis.

简介：IntroductionFritillariahupehensisHsiaoetK.C.HsiaisaliliaceousplantgrowinginthesouthwestdistrictofHubeiProvince,China.ItsbulbshavebeenrecordedinthePharmacopoeiaofthePeople′sRepublicofChinaasoneoftheprincipaltraditionalChineseherbsnamed"Hubeibeimu"[1].

简介：Tris)(η5-cyclopentadienyl-μ-carbonyl-iron)-μ3-nitrosylclusterwasobtainedfromthereactionofcyclopentadienyldicarbonylirondimerwithnitrogenmonoxideinxylene.Theclusterwascharacterizedbyelementalanalyses,IR,MSand1HNMR.Thecrystalstructureof[(η5-C5H5)(μ-CO)Fe]3(μ3-NO).C4H8OwasdeterminedbyX-raydiffractionanalysis.ItcrystallizesintheorthorhombicspacegroupPnma,a=9.053(2),6=10.545(2),c=22.525(4)A,V=2150.3(7)A3,Z=4,Dc=1.68g.cm-3;structuresolutionandrefinementbasedon1141reflectionswithI>3.0(I)(MoKa,A=0.71073A)convergedatR=0.0540.Theinfraredabsorptionbandat1325cm-1oftheμ3-NOinthecluster,whichisredshifted,showsthatμ3-NOisactivated.

简介：在CCSD(T)/6-311G(d,p)∥B3LYP/6-311G(d,p)水平上给出了反应C2H3+NO2的详细势能面信息,并列出了中间体和过渡态的几何构型.通过深入分析反应路径及反应机理,得到5个能量可行的产物和6条反应通道,其中产物C2H3O+NO的形成更有利,而产物CH2CO+HNO则是次要产物,其他产物在通常条件下可以忽略.

简介：Amodelstudyleadingtothepreparationoftheuniquetricyclo[6.2.1.0]undecaneBCDringsystemsofaconitineisdescribed.Thesynthesisfeaturesanunprecedenteddiastereoselectiveoxidativedearomatization/dimerization/retro-DA/IMDAcascadereactionandahighlyefficientWagner-Meerweinrearrangement.

简介：有N-(2-propionic酸)的新奇金轧(III)建筑群-salicyloylhydrazone(C10H10N2O4，H3L)并且1,10-phenanthroline(C12H8N2，phen)被准备并且描绘。水晶结构[Gd(H2L)(HL)-(H2O)3]2潲楰湯捩???慳楬祣潬汹?票牤穡湯??ㄠ??桰湥湡桴潲楬敮???????楢慯瑣癩瑩？

简介：ThreeC2-symmetric(10R,11R)-diethylsubstituteddibenzosuberane(DBS)-basedheliceneswithvaryingstericandconjugationdemandsoftheirbottomfragmentsweresynthesized.Onlythehelicene-7a[withthebottompartderivedfromtetralonewasfoundphoto-switchableinreasonabletimescale.Photoisomerizationofthediastereomericallypure(10R,11R,P)-helicene(7a)at280nmledtovirtuallyexclusiveformationoftheoppositeMform-diastereomer7a′(7a′/7a=99.6/0.4).Thepreferentialreturnof7a′to7acanbeeffecteduponirradiationat254nm(7a′/7a=3G/67)orthermallyat1307a′/7a=0/100).Thephoto-inducedswitchingprocessamountstoa133%differenceind.e.(from99.2%to-34%).TheconcomitantchangeofhelicenechiralitybetweenthesetwodiastereomericphotostationarystatesaugurswellfortheirpotentialapplicationasanopticalswitchinLCmaterials.Toourknowledge,oursystemservesasthebestchirochromicopticalswitchascomparedtotheexamplespossessingsimilarphotochromicproperties.

简介：Thethree-phasesbehaviorinthequaternarystsemofn-dodecylpolyglucosideC12G1.46/1-butanol/cyclohexane/waterhasbeenstudiedat40℃intermsofthevariablesγandδ.Increasingδatconstantγcausesaphaseinversionfromanoil-in-watermicroemulsionincontactwithexcessoil(winsorIor2)toawater-in-oilmicroemulsionincontactwithexcesswater(winsorⅡor2)viaamiddle-phasemicroemulsionincontactwithexcessoilandwater(winsorⅢor3).Bytakingintoaccountthedifferentsolubilitiesofalkylpolyglucosideand1-butanolintheoilphase,thecompositionofthehydrophile-lipophilebalancedinterfacialfilminthemiddleofthethree-phasebodycanbecalculated.Theeffectsofdifferentoilsandaqueousmediaonthephasebehaviorandonthecompositionoftheinterfacialfilmandtheefficiencyforalkylpolyglucosidetomakeequalweightsofwaterandoiltoasinglephasewereinvestigated.Itwasfoundthattheoilmoleculeswithsmallmolecularvolumescanimprovethesolubilizingefficiencyofthesurfactanttoformsingle-phasemicroemulsion.Ininorganicsalt(NaCl)andacid(HCl)solutions,less1-butanolisneededthanthatinalkali(NaOH)solutiontoformmiddle-phasemicroemulsion.

简介：水溶性的维生素C是一种人体必需的营养物质.维生素C是含有烯二醇基的多羟基内酯结构,利用其水溶液在波长265nm处有较强烈的紫外吸收峰,建立了直接用紫外分光光度法测定新鲜蔬菜中维生素C含量的方法.实验结果表明,维生素C的含量在1.0～12.0μg/mL内线性关系良好,线性方程为A=0.06603c＋0.01974（R2=0.99751）,检出限为0.044μg/mL,样品加标回收率为97.5％～105.4％.方法操作简单,准确度高,对新鲜蔬菜的测定结果令人满意.

简介：基于C，B,N和Ga与H原子间的L-J势函数，系统计算了H2处于（n，n,）（n=8，10，12）单壁C，BN和GaN纳米管内部及外部不同处的势能．根据势能变化曲线，分析了3种纳米管氢物理吸附能力的差异，给出了H2在3种纳米管外部的势能表达式．研究结果表明：3种纳米管内部的氢吸附力均分别高于管外；随着纳米管直径的增加，各纳米管管内的氢吸附力均略有下降，而管外变化不明显；GaN，BN和C纳米管依次具有更好的储氢能力．

简介：采用密度泛函B3LYP/6-311G（d,p）方法对CH3F与C2H3的反应体系进行了理论研究,获得了反应的势能面信息及可能的微观机理.在QCISD（T）/6-311＋＋G（d,p）水平上精确计算了各反应物种的单点能.结果表明,除抽提氢反应外,标题反应还存在抽提氟（R1）、消氟化氢（R2）、消氢（R3）和自由基形成（R4）四类反应.在QCISD（T）/6-311＋＋G（d,p）//B3LYP/6-311G（d,p）水平上,R1,R2,R3和R4反应的能垒分别是163.9,152.2,209.8和224.2kJ·mol-1,相应反应能为-56.6,-164.3,-2.7和-156.0kJ·mol-1,所有反应均放热,为热力学允许的反应.