简介：在有机化学中,Diels—Alder反应是一重要的反应,该反应看上去很简单,但目前仍有一些问题值得研究。本文根据部分教材出现的问题及取代基对反应活性、产物的结构等影响进行讨论。

简介：本文提出合成子的活性概念,从合成子的活性定性讨论不同结构的反应物进行Diels—Alder反应的难易程度;并且通过对合成子的结合方式重点讨论Diels—Alder双烯合成和1.3偶极环加成的方向选择性问题.

简介：TheauthorshavestudiedtheDiels-Alderreactionsbetweenfuranderivativesandmaleimidederivativesinanionicliquidandhavefoundthathigherreactivitycanbeobtainedinaproticionicliquid[Mim]Tf2Nthanintheconventionalorganicsolvent.Furthermore,intheDiels-Alderreactionsof2-and2,5-alkylfuranswithN-alkylma-leimide,thereactivityincreasesbyextendingthealkylchainlengthofN-alkylmaleimide.Inaddition,itwasdemon-stratedthatendo-selectivityincreaseswhen2,5-disubstitutedfuransareused.TheseresultswillbeexplainedbycomparingthestabilityoftheDiels-Alderadductwiththatoftheproductsobtainedfromthereactionsof2-substitutedfuransand2,5-disubstitutedfurans.更多还原

简介：TostudytheintramolecularDiels-Aldercycloadditonof2H-chromen-2-oneasadiene,aseriesofchiralN-allyl-N-benzylamidesthatcontaina2H-chromen-2-onemoietyweredesignedforthesynthesisofbenzo[f]isoindol-l-onesviaanintramolecularDiels-Alderandasubsequentretro-Diels-AldercycloadditionwiththeexpulsionofCO2.Boththeyield（80%-89%）andabsolutestereocontrolofthetandemreactionwerehighwhenanelectron-withdrawinggroupwasattachedtothedienophile.Thedoublebondinthestyrenesubstructureremainedintheproductscouldbefurtherderivatizedbydihydroxylation.

简介：马来酰亚胺树脂是一类理想的耐热高分子材料,作为马来酰亚胺的前体原料马来酸酐,双键的存在往往会降低高分子材料的稳定性,利用Diels-Alder反应保护马来酸酐中的碳碳双键成为发展性能更优越的马来酰亚胺耐热高分子材料的可行方法。文章运用Wolff-Kishner-Huang反应还原糠醛制备2-甲基呋喃,并对反应溶剂及相转移催化剂进行TLC跟踪优化;同时成功合成出2-甲基呋喃与马来酸酐的Diels-Alder反应产物,保护了马来酸酐中的双键,具有重要的实践意义。

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简介：属于胡颓子科,渐危种。种仁含油量高,可供食用;花含蜜量大;根系发达,根瘤固氮可改良土壤;叶含氮量较高;材质坚硬。本种既是木本油料植物、密源植物和用材树种,又是干旱地区营造水土保持林的优良树种,故其经济价值较高。生于海拔800-1500米的山坡,多见于阴坡和半阴坡,阳坡也有分布。

简介：AIMThepreviousworkhasdemonstratedthatthepolysaccharidesofAngelicasinensis(Oliv.)Dielshavesignificantlyantitumoractivityandindicatedthattheactivityisstronglydependentontheirstructures.However,therelationshipsbetweenthestructureandtheactivitiesarestillambiguous.Thus,atpresent,moreeffortsarebeingexpendedinseekingtoisolatethepolysaccharidesfromAngelicasinensis(Oliv.)Diels,measuretheirstructuralfeaturesandantitumoractivities,andelucidatestructure-activityrelationshipsofpolysaccharides.METHODSTherootsofAngelicasinensis(Oliv.)DielswereextractedWithwater,separatedbySephacrylS-400andDEAE-sephadexA-25columnsandfurtherpurifledonSephadexG-100column.