1,2,4-恶二唑的合成综述

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1、PharmaceuticalChemistryJournalVol.39,No.10,2005DRUGSYNTHESISMETHODSANDMANUFACTURINGTECHNOLOGYSYNTHESISOF1,2,4-OXADIAZOLES(AREVIEW)L.A.Kayukova1TranslatedfromKhimiko-FarmatsevticheskiiZhurnal,Vol.39,No.10,pp.32–40,October,2005.OriginalarticlesubmittedSeptember2,2003.Method

2、susedforthesynthesisof3,5-substituted1,2,4-oxadiazolesarereviewed.Thesynthesesarebasedmostlyontheuseofprimaryamidoximesandacylatingagentsastheinitialreactants.Thepathwaytoanotherlargegroupof1,2,4-oxadiazolesproceedingfromabroadspectrumofreactantsisviatheirreactionsof1,3-d

3、ipolarcycloaddition,inparticular,withprimaryamidoximes.Thewell-knownreactionsofamidoximesarethosein-toO-acetylamidoximes(IIa,IIb);O-benzoylderivativesvolvingtheiracylation,whichhavebeenthoroughlystudied(IIc–IIf)wereobtainedviathereactionsofamidoximessince1920–1930[1–3].Th

4、emajorityofpublicationsde-withbenzoicacidchloroanhydridesinpyridine.Thesubse-votedtothechemistryofamidoximesinrecentyearsrefertoquentthermolysisofoneoftheseproducts(O-acetylami-thesynthesisofO-acylatedamidoximesand1,2,4-oxa-doximeIIa)leadsto1,2,4-oxadiazoleIII[8].diazoles

5、,whichareamongthemostreadilyaccessibleheterocycles.BeingbioisostericwithesterandamidegroupsRRRandproducingasignificantincreaseinthebiologicalactiv-OOOity,1,2,4-oxadiazoleshavebeenextensivelystudiedwithaNNOHNNOCOR2Nviewtotheiruseinthepharmaceuticalchemistry[4–7].NOR1CHC1As

6、ingle-stagesynthesisof1,2,4-oxadiazoles,besidestheRCHCCH2CpathwayviadehydrationofO-acylatedamidoximes,isviaNH2NH2NCIIIIIIMetheinteractionofamidoximeswithcarbonyl-containingreac-12tants(esters,amides,acids,aldehydes)aswellaswithI–III:R=H(a,b),Ph(c,d);R=H(a,c),Me(b,d);R=Me(

7、a,b),Ph(c,nitrilesandN-oxides.Analternativepathwayto1,2,4-oxa-d),o-ClC6H4(e),p-ClC6H4(f).diazolesisbasedonthe1,3-cycloadditionofN-oxidestoAromaticamidoximesinteractwith5-aryl-2,3-dihydro-azomethines,nitriles,andiminoesters.furan-2,3-dionesatroomtemperaturewiththeformation

8、of1.AcylationofAmidoximeswithChloroanhydridesO-arylpyruvoylamidoximes(IV–IX).WhenheatedtoandAnhy