醚、氨基及氨基酸的各种保护基及去保护方法大全

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1、醚、氨基及氨基酸的各种保护基及去保护方法大全（整理有详细操作）[Acetate][Benzoatel][Pivaloate][Levulinate][BacktoCarb.Synthesis]Ac-(acetate)esterStandardProtectionProcedureToasolutionoftheglycosideindrypyridine(25eq)underaninertatmosphereatroomtemperature,aceticanhydride(10eq)isaddedandstirredu

2、ntilcompletebyTLC(usually16h).Thereactionmixtureisthenpouredintoice/waterandextractedthreetimeswithchloroform.Thecombinedorganiclayersareextractedwith3%HCl,saturatedaqueoussodiumbicarbonate,andwater.Theorganiclayeristhendriedandconcentratedinvacuo.Theresultingres

3、idueispurifiedbyflashchromatography(SiO2)ifnecessary.RemovalTheglycosideisdissolvedinmethanolandasolutionofsodiummethoxideinmethanol(0.1eqper-OAc)isaddeddropwiseat0°.ThesolutioniswarmedtoroomtemperatureandstirredunderaninertatmosphereuntilcompletebyTLC(usuallywit

4、hinafewhours).AmberlitecationicexchangeresinisthenaddedwithvigorousstirringuntilthepHofthemixtureisneutral.Themixtureisthenfilteredandconcentrated.Theresultingresidueispurifiedbyflashchromatography(SiO2)ifnecessary.ORTheGlycosideisdissolvedinmethanolandhydrazineh

5、ydrate(15eqper-OAc)isaddedintwoportionsover1.5hours.ThesolutionisstirredatroomtemperatureunderaninertatmosphereuntilcompletebyTLC(usually6hours).Thesolutionisthenneutralizedwithglacialaceticacid.Themixtureisfilteredthroughceliteandconcentrated.Theresultingresidue

6、ispurifiedbyflashchromatography(SiO2)ifnecessary.ReferencesJ.Org.Chem.,1996,61,6442-6445."SyntheticMethodsforCarbohydrates"Lemieux,Ch6,pg.90-115.J.Chem.Soc.,PerkinTrans.1,1996,985-993.Bz-(benzoate)esterStandardProtectionProcedureToasolutionoftheglycosidedissolved

7、indrypyridine(0.3M),benzoylchloride(4eqper-OH)isaddedatroomtemperatureunderaninertatmosphereandstirreduntilcompletebyTLC(usually16h).Methanolisaddedandthesolutionwasconcentratedinvacuo.TheresiduewasdissolvedinDCMandwashedwithwater,saturatedcoppersulfate,andbrine.

8、Theorganiclayerisdriedandconcentratedinvacuo.Theresultingresidueispurifiedbyflashchromatography(SiO2)ifnecessary.RemovalTheglycosideisdissolvedinMeOHandasoluti