Further functional group oxidations using sodium perborate

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1、TetrahedronVol.45,No.II,pp.3299to3306.1989lm4&4020/89$3.00+.ooPrintedinGreatBdain.01989PergamonPressplcFURTHERFUNCTIONALGROUPOXIDATIONSUSINGSODIUMPERBORATEALEXANDERMcKILLOP”ANDDUNCANKEMPSchoolofChemicalSciences,UniversityofEastAnglia,Norwich,Norfolk,NR47TJ,England.(Rec

2、eivedinUSA26September1988)Abstract-Sodiumperborateinaceticacidisaneffectivereagentfortheoxidationofaromaticaldehydestocarboxylicacids,iodoarenesto(diacetoxyiodo)arenes,azinestoN-oxides,andvarioustypesofsulphurhetero-cyclesto--S,S-dioxides.Nitrilesareunaffectedbythereag

3、entinaceticacid,butundergosmoothhydrationtoamideswhenaqueousmethanolisemployedassolvent.Sodiumperborateisaverycheap,safeandeasilyhandledoxidant(stable,colourless,crystallinesolid)whichwehaveshownrecentlytobeahighlyeffectiveand,insomecasesselective,reagentfortheconversi

4、onof(1)anilinesintonitroarenes;(2)sulphidesintosulphoxidesorsulphones;(3)N.N-dimethylhydrazonesintoketones;(4)ketonesintoesters(Baeyer-Villigeroxidation);and(5)hydroquinonesandphenolsintobenzoquinones.’Wehavecontinuedourstudyoftheuseofsodiumperboratefortheoxidationoffu

5、nctionalgroupsandnowconcludeoursurveywithdetailsof(A)theoxidationofaromaticaldehydestocarboxylicacids;(B)theconversionofiodoarenesto(diacetoxyiodo)arenes;(C)theoxidativehydrationofaromaticnitrilestothecorrespondingamides;(D)theoxidationofx-deficientazinestoN-oxides;and

6、(E)theconversionofavarietyofsulphurheterocyclestothecorrespondingz,S-dioxides.Aswiththetransformationsdescribedpreviously,theoxidations(A)-(E)caneasilybescaledup,andgiventheadvantagesofsodiumperborateoutlinedabove,togetherwiththecompleteabsenceofeffluentorby-productpro

7、blems,webelievethatit.couldwellprovetobethereagentofchoiceforatleastsomeofthesetransformations.A.OxidationofAromaticAldehydestoCarboxylicAcidsTreatmentofavarietyofaromaticaldehydeswithsodiumperborateinaceticacidat50-55OCresultedinsmoothoxidationtothecarboxylicacids,and

8、yielddataaresummarisedinTableI.Thereactionproceedswellwithaldehydes32993300A.MCKILLOPandD.KEMPTableIOxidationofaromat