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Pictet–Spengler reaction
(2023-02-05 12:45:02)

ThePictet–Spenglerreactionisachemicalreactioninwhichaβ-arylethylamineundergoescondensationwithanaldehydeorketonefollowedbyringclosure.Thereactionwasfirstdiscoveredin1911byAméPictetandTheodorSpengler(February22,1886-August18,1965).Traditionallyanacidiccatalystinproticsolventwasemployedwithheating,howeverthereactionhasbeenshowntoworkinaproticmediainsuperioryieldsandsometimeswithout...[阅读全文]
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Bischler–Napieralski reaction
(2023-02-05 12:31:43)

TheBischler–Napieralskireactionisanintramolecularelectrophilicaromaticsubstitutionreactionthatallowsforthecyclizationofβ-arylethylamidesorβ-arylethylcarbamates.Itwasfirstdiscoveredin1893byAugustBischlerandBernardNapieralski,inaffiliationwithBasleChemicalWorksandtheUniversityofZurich.Thereactionismostnotablyusedinthesynthesisofdihydroisoquinolines,whichcanbesubsequentlyoxidizedtoiso...[阅读全文]
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Duff醛基化反应
(2023-02-05 10:58:55)

TheDuffreactionorhexaminearomaticformylationisaformylationreactionusedinorganicchemistryforthesynthesisofbenzaldehydeswithhexamineastheformylcarbonsource.ItisnamedafterJamesCooperDuff,whowasachemistattheCollegeofTechnology,Birmingham,around1920–1950.TheelectrophilicspeciesinthiselectrophilicaromaticsubstitutionreactionistheiminiumionCH2+NR2.Theinitialreactionproductisaniminiumwhichishydrolyz...[阅读全文]
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一种简易方便的去除脱硅反应中TBAF的方法
(2023-02-04 10:28:23)

Silicon-basedprotectinggroupsarecommonplaceinsyntheticroutestocomplexorganicmolecules.Theirabilitytobeintroducedundermildconditions,aswellastheirstabilitytowardharshreactionconditions,hasmadethemawidespreadtoolinorganicsynthesis.Smallsilylprotectinggroups,suchasthetrimethylsilylgroup,canberemovedunderbasicoracidicconditions,butlargersilylprotectinggroupsaregenerallyremovedunderfluoride-mediatedcon...[阅读全文]
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ion exchange chromatography
(2023-02-02 16:28:47)

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Paal-Knorr Pyrrole Synthesis
(2023-02-01 20:36:48)

Paal-KnorrPyrroleSynthesisThePaal-KnorrPyrroleSynthesisisthecondensationofa1,4-dicarbonylcompoundwithanexcessofaprimaryamineorammoniatogiveapyrrole.Thereactioncanbeconductedunderneutralorweaklyacidicconditions.Additionofaweakacidsuchasaceticacidacceleratesthereaction,buttheuseofamine/ammoniumhydrochloridesaltsorreactionsatpH<3leadtofuransasmainproducts(Paal-KnorrFuranSynthesis).Paal-KnorrFuranS...[阅读全文]
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Synthesis of homoallylic alcohols
(2023-02-01 20:04:09)

Alder-EneReaction
EneReactionhefour-electronsystemincludinganalkeneπ-bondandanallylicC-Hσ-bondcanparticipateinapericyclicreactioninwhichthedoublebondshiftsandnewC-HandC-Cσ-bondsareformed.ThisallylicsystemreactssimilarlytoadieneinaDiels-AlderReaction,whileinthiscasetheotherpartneriscalledanenophile,analogoustothedienophileintheDiels-Alder.TheAlder-EneReactionrequireshighertempera...[阅读全文]
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TPAP (Ley-Griffith) Oxidation
(2023-01-29 15:06:09)

TheoxidationofalcoholstoaldehydesorketonescanbecatalyzedbyTPAP(nPr4N+RuO4–;TetraPropylAmmoniumPerruthenate)whichisair-andmoisture-tolerantandalsosolubleinorganicsolvents.Itisnotasstronglyoxidizingasrutheniumtetroxideanddoesnotcauseolefincleavageoroveroxidationofaldehydestocarboxylicacids.Simpleprocedureandtheautocatalyticnatureareotherimportantcharacteristics.Themildreactionconditionsareespe...[阅读全文]
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hydride reduction
(2023-01-29 14:43:02)

L/N/K-SelectrideThereagentshavingtheformulaM[HB(sec-Bu)3]areusedasreducingagents.Therearethreetypeswithdifferentcations:L-Selectride(lithium),N-Selectride(sodium),andK-Selectride(potassium).Becauseofthesec-butylgroups,thesereducingagentsaresensitivetostericinfluencesandoftenallowforchemo-andstereoselectivereductions.ThechemoselectivityofM-Selectridereductionisstronglyinfluencedbythestericandsolven...[阅读全文]
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一喝酒就脸红？这是危险信号！
(2023-01-25 19:45:41)

酒，一般的组成是水+酒精 （酒不同，酒精比例也不同） 酒精在消化道中不需要消化即可吸收 它们能够迅速进入血液 可以压抑某些大脑中枢活动 这些中枢平时像镇定剂一样 管着你的情绪 酒精还会影响大脑的海马体 这是大脑转化记忆的部分 一旦这部分被干倒了 就会出现喝酒断片的现象 进入人体的酒精 10%会通过呼吸以及尿液和汗液排出 [阅读全文]
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