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1、LettersinOrganicChemistry,2008,5,495-501495Silica-SupportedDichlorophosphateCatalyzedBeckmannRearrangementandDehydrationofOximesUnderMicrowaveIrradiationZhengLi*andZhongLuGansuKeyLaboratoryofPolymerMaterials,CollegeofChemistryandChemicalEngineering,NorthwestNormalUniversity,
2、Lanzhou,Gansu,730070,PRChinaReceivedNovember23,2007:RevisedMay18,2008:AcceptedJune04,2008Abstract:Silica-supporteddichlorophosphatehadbeenprovedtobeanefficient,recoverableandreusablecatalystforBeckmannrearrangementofavarietyofketoximesanddehydrationofvariousaldoximesinTHFund
3、ermicrowaveirra-diation.Thisprotocolhasadvantagesofhighconversion,highselectivity,shortreactiontime,noenvironmentalpollutionandsimplework-upprocedure.Keywords:Beckmannrearrangement,dehydration,silica-supporteddichlorophosphate,oxime.INTRODUCTIONVeryrecently,SiO2-supportedcat
4、alystssuchasSiO2-supportedsulfuricacid[24]andMoO3[25]havebeenre-Amidesandnitrilesareofparticularinterestinprepara-ported,whichcouldefficientlyresolvetheseparationprob-tiveorganicchemistry.Greateffortshavebeenmadetopre-lemandthereforeeliminatethepollutioncausedbythepareamides
5、fromBeckmannrearrangementofketoximesabovecatalysts.andnitrilesfromdehydrationofaldoximes[1].Theconven-OClPClOClPClClHHHOOOOOOMWIOOSiSiSiSiSiSiSiSi+HCl(g)OOO12minOOOSiO2OHSiO2OPOCl2Scheme1.tionalBeckmannrearrangementofketoximesanddehydra-Inaddition,Beckmannrearrangementofketo
6、ximesandtionofaldoximesusuallyrequiretheuseofstrongBronsteddehydrationofaldoximeswerealsoreportedtoconductun-orLewisacids,i.e.concentratedsulfuricacid[2],trifluoro-dermicrowaveirradiationcondition[26],whichcouldsig-methanesulfonicacid[3]andpolyphosphoricacid[4],whichnificant
7、lyacceleratethereactionrate.alwayscausetheenvironmentalproblemsbecauseoftheIncontinuationofourresearchonsilica-supportedcata-difficultyinseparation.lystsfortheimportantchemicaltransformation[24a,27],inRecently,Beckmannrearrangementofketoximeswasre-thispaper,wereportsilica-su
8、pporteddichlorophosphateasportedtoutilizemanykindsofcatalysts,suchas(EtO)2P
