氰转化为酰胺

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1、经典合成反应标准操作—Mitsunobu反应经典化学合成反应标准操作目录1．前言…………………………………………………………………22．氰基转化为酯…………………………………………………………23．氰基转化为酰胺…………………………………………………23.1丙稀酰胺的合成…………………………………………………………23.2苯乙酰胺的合成…………………………………………………………3Page5of6经典合成反应标准操作—Mitsunobu反应6.从氰基合成酰胺6.1氰基水解腈加水可以分解为伯酰胺。由于伯酰胺会继续水解为羧酸，一般要控制水解的条件。目前有许多方法报道，有时需要根据

2、底物的特性选择酸性，碱性或中性的水解条件。作为中性的条件，也有文献报道使用镍或钯催化剂的方法。在酸性条件下与饱和碳相连的氰基，可以在酸中很方便的水解转化为酰胺，并在条件较为剧烈时，很容易进一步水解成酸。但乙烯基或芳基腈的水解条件则要求剧烈得多，一般需要强酸条件，而且一般不会进一步水解。在碱性条件下，利用过氧化氢氧化的方法可在室温下短时间内水解腈为伯酰胺，这是一个较为可靠的方法。利用NaOH(aq.)-CH2Cl2相转移催化体系，DMSO-K2CO3体系[2]可以用于各种腈水解为伯酰胺。6.1.1盐酸水解腈为伯酰胺示例[3]Ina3-l.three-neckedround-bo

3、ttomedflaskequippedwithglassjointsareplaced200g.(1.71moles)ofbenzylcyanideand800ml.of35%hydrochloricacid.Theflaskisfittedwitharefluxcondenser,athermometer,andanefficientmechanicalstirrer.Atabathtemperatureofabout40°themixtureisstirredvigorously.Withinaperiodof20–40minutesthebenzylcyanidegoe

4、sintosolution.Duringthistime,thetemperatureofthereactionmixturerisesabout10°abovethatofthebath.Thehomogeneoussolutioniskeptinthebathwith,orwithout,stirringforanadditional20–30minutes.Thewarmwaterinthebathisreplacedbytapwateratabout15–20°,andthethermometerisreplacedbyadroppingfunnelfromwhich

5、800ml.ofcolddistilledwaterisaddedwithstirring.Aftertheadditionofabout100–150ml.,crystalsbegintoseparate.Whenthetotalamountofwaterhasbeenadded,themixtureiscooledexternallywithicewaterforabout30minutes.Thecooledmixtureisfilteredbysuction.Crudephenylacetamideremainsonthefilterandiswashedwithtw

6、o100-ml.portionsofwater.Thecrystalsarethendriedat50–80°.Theyieldofcrudephenylacetamideis190–200g.(82–86%).Page5of6经典合成反应标准操作—Mitsunobu反应6.1.2浓硫酸水解不饱和腈为伯酰胺示例[4]To106gof84%sulfuricacid,wasadded50gofacrylonitrile.Afterstirringfor30minatr.t.,theresultingmixturewasheatedto95℃,andstirredfor2h.Aft

7、ercooling,thesolidwascollectedbysuction,andthefiltercakewastransferredintoabeaker.Totheice-cooledsolid,wasaddedaq.ammoniawiththespeedthatkeepthetemperaturelessthan50℃.Theprecipitatedammoniumsulphatewasfilteredoff,andthefiltratewascooled.Theprecipitatewas