Synthesis of 2-Arylbenzofuran: Confirmation of the Structure of Gnetifolin A

GnethelinAu'asisolatedfromGnetumparvghlium(Warb.)C.Y.Chengb}'Lietal.'ItSstructUrextasproPosedpre\'iousl}'as2-(3.5allhydroxT4-methomphen}l)-3-methony-5-hydrox3-benLzofiiran(l).Aner9'nthesisofset1eralanalogsofStrUctUre(l),theStrUCtUrofGnetjfolinAseemstobenustakenanduasrerisedas2K3-5allhydrOny4-methomphenyl)4-methoxy-5-hvdrowtenzofuran(2).=Inordertoconfirmthisrer4ndmCtUranddevelopaversahlewtehcrouteforthe9-nthesisofGnetjfolinAandanalogs,2T-edSyl4-methoxy-5-hydrotwllZofuran(3)u'asselec…     

Synthesis and Electrochemical Properties of a New Tetraazamacrocyclic Complex of Silver (Ⅰ)

Themetalmacrocycliccomplexeswiththeirunusualoxidationstateshaveattractedmuchinterest.Silver(Il)andsi1ver(IlI)compoundsareusuallyunstab1eduetotheirstrongoxidation.Butsometetraazamacrocyclicligandscandirectlygivestablecom-plexesofsiIver(Il)throughdisproportionatedreactionofsilver(I).12fIere,wereportthesynthesisandeIectrochemicalbehaviorofanewsilver(Il)com-plexAgL(CIO')2(L=5,7,l2,l4-tetraethyl-5,l2-dimethyl-l,4,8,ll-tetraazacyclotetradec-4,l1-diene).Therelativeinformationaboutothersilver(1I…     

An Improved Synthesis of dl-Muscone

Muscone.aprincipalodoriferousconshtUent,wasisolatedb3WaIbauminl9O6frOmmuskPodobtainedfromthemalcmuskdeerMo,9cusmoschghnJ'],anditSsthectUret`asdetenninedas(R)-(-)-3-methyl-q'lopentadeCano.eI2l.AnlongnumerousSynthehcmethodsformusconesofarrePOrtedl'-'].theclassicaloneisintramolecularaldolcondensahonof2,l5-hexadecanedjonecamedoutb}'M.Stolllo].However,theshortryntheticschemehasbenhadtwoinherentproblems.ThefirstproblemisagndSynthehcmethodforthedsetone3andthesecondoneisagoodmethodofaldolconde…     

Total Synthesis of (+)Villosol

Villosol,aniridoid,wasisolatedin1985fromChineseherbmedicineP8triniaviIios8'itSstrUctUrewasproPOsedas(A)ll].lnourpreviouspaperi2],wehavereP0rtedthesynthesisofthesubstance(l)A,andf0undittobesPectraIlynonidenticalwiththenaturalisolate.Later,throughX-rayanalysisl'],wehaveconfirmedthatthesmictUreofvillosolwasB.Herein,wedisclosethefirstStereoselectivetotalsynthesisof(+)B.Oursynthesisbeganwithcompound2,whichwasreadilypreparedandresolvedtoitSoPticalformsinlargescalebyAnownmethodI41.After(l)2w…     

Studies on the Electrochemical Reduction of Cyanocobinamide

l.INTR0DUCTIONVitaIninBlz(cyanocobalamin)anditScoenZymesasmostdrip0rtanmoleculeshavebeenextensivelystUdied.However,themetabolicreacti0nsofvitaIninBl2throughWhichtheintuellarconversi0ntoitSc0empeformsinmanunaliancellsarelargelyunkn0wnanduncharacterized[l].SeverallinesofevidencesuggestedthatvitaIninBl2mustbereducedpri0rtoformingitsc0e~es[2].Thus,theconversionofvitaIninBl2toitSc0enZyIneformsincellsneedsreductionreagents,suchasFMNapdNADHwithreducedglutathione[l].lnaddition,itwasreP0r…     

The Reaction of Benzimidazole Methiodide Salt with Bis-Grignard Reagent

l.IntroductionWerePortedthereachonofl,2,3-trisubshtutedbnddazoliumsaltwithGrignardreagentandanovelwteticmethodforketoneswasprovided.l'jInthispaPer,thereachonofl,3-disubstitUtedbetridazollumiodidewithbis-Grignardreagentisstudie4l,6-hexanedialdehydeispreparedfromtheaddihontwdrolysisreactionofl,3-di!nethylbchdazoliumiodidewtbis-ongnardreagentanewwteticmethodfordialdehydeisprovided.TheconyersionofaGrignardreagentoanaldehydehasbeenaccomplishedbyavtrietyofreagents.['J]Meyersetal.rePortedtheconve…     

Metabolites of Icariin in Urine Following Oral Administration

YinyanghuohasbeenusedinfolkmedicineforthousandsofyearsinChina.ItbelongstoplansofgenusEpimedinm(Berberidaceae).ChinaPharmcopoeia(l995Ed.)c0llectedfivespeciesofEpAnedium,inwhichflavanoidsareregardedastheprinciPalcomPonentsresponsibleforthePharmacologicalactivitiesofYinyanghuo,suchastonic,anti-hyPertensiveandami-inflarnmatoryactions.Icariinisoneofthemainflav0n0idconstituentsinYinyanghuo"'andextensivelyusedtocontrolthequalityofthecmdedrug."'TherearemanyrePortsonthepharmac0l0gical,chendcaland…     

Cycloaddition of benzoheteroazepine Ⅲ Reaction of 2,3-dihydro-lH-l,5-benzodiazepines with dichlorocarbene and stereo-structures of products

Reaction of 2,3-dihydro-1H-l,5-benzodiazepines with dichlorocarbene generated in situ using benzyltriethylammonium chloride (TEBA) as a phase transfer catalyst in chloroform-aqueous sodium hydroxide mixture gave mainly 1,2-cycloadducts, as and trans-la,3-disubstituted-1, 1-dichloro-1a,2,3,4-tetrahydro-1H-azirino[l,2-a][l,5]benzodiazepines (2,3), and formylated 1,2-cycloadducts, trans-la,3-disubstituted-l, 1-dichloro-4-formyl-1a,2,3,4-tetrahydro-lH-azirino[l,2-a][l,5]benzodiazepines (4). The stereo-structures of cycloadducts and the mechanism are also discussed.     

Determination of the Atomic Weight of Germanium

IntrOduedon:ThemodPodedcattalcwegheqailtheelementsisPr~thatofge~Um,A.(Ge.~cuous~aslargaso.o4ekiStS~nthe~Ge)detenninedtymass~andthatfoundtytheclassitalchthetalInethod').ThePreSentinveedghonaimsatCarryinouathetutetheonmeasurmentusingthetrueisotwicbooofGa6,nl=l.5o676(39)fOundtyMachlanetaLinacali~tnass~cmecmenP,wherethevaluewithintbebracketsindibestheerrorofthelaStbodigitS.ooumandge~umareneighborsintheperiedcSystmQfelements.TheformrisbinpelidicandhasisotpewithmassnUmbosas69and71,whereas~u…     

Metabolites of Icariin in Rat Bile Following Oral Administration

Yinyanghu0hasbeenusedasafolkmedicineforthousandsofyearsinChina.ItbelongstoplantSofgenusEpimedium(Berberidaceae).ChinaPharmacopoeia(l995Ed.)collectS5speciesofEpimedium,inwhichflavanoidsareregardedasprincipalcomP0nentsresponsibleforthepharmacologicalactivitiesofYinyanghu0,suchastonic,antihypertensiveandantiinflanunatoryactions.IcariinisoneofthemainflavonoidconstituentSinYinyanghuo"'andextensivelyusedtocontrolthequalityofthecrudedrug"'.Asapartofourstudiesonthebi0l0gicalfateoficariin(datanots…     

Investigation of the Structures of the Product Ions Produced via self-CI of Acetone

TheacetoneselfCImassspectrumAcetoneselfCImassspectrumisgiveninTable1.Table1.MajorproductionsandtheirrelativeabundanceofacetoneselfCIMSTheformationofionatmlZ73AnotherproductionintheselfCIMSofacetoneistheionatm/z73.InselfCIMSofacetone-d6,thecounterpartistheionatInjz82.InselfCIMSofthemixtureofacetoneandacetone-d6inaratioofl:l,thecorrespondingionsaretheionsatInlz73,76,79and82.TheirCIDreactionresultsarelistedinTable2.Table2.TheCIDMSoftheionatIn/z73andanalogsOnthebasisofthedatainTab…     

Elimination Reaction of α,ω-Diols by Magnesium

Inrecentyears,someapplicationsofmagnesiuminorganicsynthesisandorganosiliconreactionshavebeenreported""'.Here,wewishtoreportanothernewreaction,theelindnationreactionofsomediolsbymagnesium.Inthepresenceofiodine,l,3-propanediol,l,4-butanediolorl,5-pentanediolreactswithmagnesiumtoproducemagnesiumalkoxides.Whenthemixtureofformedmagnesiumalkoxideinalcoholwasrefluxed,thermaldecompositionoccurswiththeformationofcyclicethersand,respectively,allylalcohol,buten-l-olandpenten-l-ol.Thetotalreactioncorrespo…     

Total Synthesis of (±)Hinesol

Hinesollanditsrelatedspiro[4.5]decenesesquiterpeneagarospir0l2wereisolatedfromavarietyofplants.Althoughmanmethodshavebeendevelopedfortheirsynthesis,fewofthemgivesatisfactoryresults,especiallywithcontrolofstereochendstryatthespirocenteraswellinC2andC1O.Inl985,YangreportedthattWonewspiro[4.5]decenesesquiterpenes,whichhaveunusualbiologicalactivity,wereis0latedfromAquilariasinensiS(Lour.)Gilgandnamedbadrixinicacid3andbairnuxinal4l.InordertostUdytheirsmictUre-activityrelati0nshiPfurther,wehave…     

Two New Amides from the Roots of Acorus Tatarinowii Schott

AcorustatarinowiiSchottiswidelydistributedinChinaItisatraditionalhefbmedcineinChinaandusedasadigestan,anexpectoranandasanimulanagainstdigttveedisorders,diarrheaandepilepsy.InordertoelucidaetheStrUctUresOfitsactiVePrinciples,weSySteInaticallyStUdiedtheroosofAconatatannowtiSchott.Asaresultofinveedgations,wenowreportthemCtUrsofbonewaInjdes,tatardrideA(1)andtatardrideB(2).COmpondlwasisolatedascolourlessoil.Icr]D-46'5lo(cO.O86,acetone).EI-MS(In/.)f28l(M+-H,o,57%),224(49%),l47(loo%),l3…     

Total Synthesis of (±) Kadsurenin M

KadsllreIlinM(7s.8s-.1.4.3'-tril1letllop'-7"oxo-n0r-8'.9'-7.0.4'.8.5'-neolignan)u'asisolatedfrollltlleaerialpart0fPiperKadsl1ra(Cl1ois}')0l1\viI'].aCllinesetraditiol1aldrugusedf0rtlletreatll1el1tofil1naI11l11ati0nundrl1eul1laticcol1diti0l1s.Aspartof0urresearcl1xt,0rkontlletotals}'lltllcsisofbe11z0fura11oidncolignans,l"ereportl1eret11efirstlotalsi'ntl1esisofkadsurenil1Masitsrecel11icfonn.Tllep-lltlleticro[1leisdepic1edi1ltl1ef0lloxt'il1gsclleme.3.4-Dilnetl1on'cil1nam}'lcllloride6.readil}'a\…     

Synthesis of Bicyclooctane Derivatives for Kinetic Resolution

Theracemicdiacetaterac-l[l]hasprovedtobeaversatilestartingmaterialforthesgnthesisofracemicprostaglandins,suchasll-deoxyPG.,1l-deoxyPGfy,PGA:,PGE,,andPGF.l:1.Bothenantiomerslandent-lcanbetransformedbyenantioc0nvergentroutCsintoenantiomericallypureprostaglandinswiththenatualconfigurationt'].Therefore,thekineticresolutionofitSprecursorrac-2(Schemel)evoked0urinterestinthisfield.CycliccompoundsofthetyPe3shouldbeidealsubstratesforkineticres0luti0noftheendo,endo,bicyclo[3.3.0]octal-2,6-diol2ri…     

Chemo-Enzymic Synthesis of a Four-Chiral-Center Portion of A-23187(Calcimycin)

A-23l87(calcimycin)[']wasisolatedfromthecultUresofstrePtomyceschartreusensiS.Itisauniquedivalentcati0nionphoreandcharacteristicallyfrOmslipophilicmetalioncomplexeswhichareeffectiveiniontransportacrosslipidbhoer.TillnowhundredsofpaPersareaccumulatingontheaPplicationofthisionphoreasaneffectivepr0befortheinvolvementofmetalionsinthecontrol0fnumerousPhysiologicalprocesses.BesidesitSspecificbiologicalfunctionsitalsohasauniquestrUctUretoattractmuchattentionofsyntheticchemist.lthassevenchiralcente…     

Total Synthesis of Saprorthoquinone

Alarge1lumberoforthoquinonenaturalproductSwereisolatedfromsalviaspecies.BioassayonU1esecompoundssl1otvedthattileyhadalotofbio1ogicalachvihessucl1asanhbacterial,corolleq'arterydilator,anhtumoretc.TlhshadledtomanSynthesesofthem.Saprorthoqninolle(l),anaturalorthOquinone,t`asisolatedfromtherootSofsaIviaPrionitisHalleel'Jl`41ichtmsusedinfolkmedicinefortrtutmentofInandiseases.Theiulhalbioassayshowedthatsaprortlloqull1onehadachvityinleukemiaPaseteSt.Recenhy,MatSumotoetal.reportedaSynthesisofsa…     

Effect of Potential Perturbation Polarization on the Stress Corrosion Cracking of Type 321 Stainless Steel

Ithasbeenwidelyacceptedthatelectrochemicalcorrosionreactionsareinvolvedinthe.stresscorrosioncrackingprocessesofmostmetaljaqueoussolutionsystems'.Accordingtothecharacteristicsofdynamicstrainatthecracktipofmetal,itisofgreatimportancetostudytheinfluenceofvariedpotentialsonthedynamicstrainprocessatcracktipbydifferentpotentialpertllrbationsbetweenanodicandcathodicpotCntials.SmoothcylindricaltensilespecimenwasusedinSSRT(strainrate4.l6x's-').Allexperimentswereperformedino.75molILHCl O.25molILNa…     

Conformational Analysis of γ-Butyrolactones by Nuclear Magnetic Resonance Spectroscopy

Conformationalanalysis[']offive-memberedringsystCms,[2]althoughofintereStbecauseofthewidespreadoccimnceofsuchSystemsinnatUre(incarbohydraes,steroids,alkaloids,nucleicarids,andcertainaminoacids),hasprogressedmuchmoreslowythanthecorresPondinganatysisofthesix-memberedhomologs,l56l:,2M=7ve27X::conformationalmobilityoffive-memberedri.gS.I$Itiscommonlyknownthatafive-memberedringekistSinanonplanarconformationanditSmoststablepuckeredformsaretheenveloPeandhalf-Chairconformations.I41TheenveloPecon…