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1、L-缬氨醇的制备方法文献OrganicSyntheses,Coll.Vol.7,p.530(1990);Vol.63,p.136(1985).REDUCTIONOFα-AMINOACIDS:L-VALINOL[1-Butanol,2-amino-3-methyl-,(S)-]SubmittedbyD.A.Dickman1,A.I.Meyers1,G.A.Smith2,andR.E.Gawley2.Checkedby(A)KarlM.Smith,ClaytonH.Heathcock,(B)AlanT.Johnson,KraigM.Yager,andJamesD.White.1
2、.ProcedureCaution!A.Becauseofthehydrogengasevolvedduringthisreaction,thisprocedureshouldbecarriedoutinanefficientfumehood.Anoven-dried,3-L,three-neckedflaskequippedwithamechanicalstirrer,aFriedrichcondenser,andanitrogen-inlettubeisflushedwithnitrogen,andthenchargedwithasuspensionoflithiuma
3、luminumhydride(47.9g,1.26mol)in1200mLoftetrahydrofuran(THF)(Note1).Themixtureiscooled(10°C,icebath)andL-valine(100g,0.85mol)isaddedinportionsovera30-minperiodfroma200-mLround-bottomedflaskconnectedtothereactionflaskviaaflexibleplasticsleevesoasnottoproducetoovigorousanevolutionofhydrogen(N
4、ote2).Aftertheadditioniscomplete,theplasticsleeveisreplacedbyastopper,theicebathisremoved,andthereactionmixtureiswarmedtoroomtemperatureandthenrefluxedfor16hr.Thereactionmixtureisthencooledagain(10°C,icebath)anddilutedwithethylether(1000mL)(Note3).Thereactionisquenchedovera30-minperiodwith
5、water(47mL)(Caution!See(Note4),aqueous15%sodiumhydroxide(47mL,over20min),andwater(141mL,over30min).Thesolutionisstirredfor30minandthewhiteprecipitateisfiltered.Thefiltercakeiswashedwithethylether(3×150mL)andtheorganicfiltratesarecombined,driedwithanhydroussodiumsulfate,andconcentratedunder
6、reducedpressure.DistillationoftheresidueundervacuumaffordsL-valinol(63.9–65.7g,73–75%)(Note5)asaclearliquid:bp63–65°C(0.9mm)(Note6):[α]D20+14.6°(neat);nD201.455;IR(neat)cm1:3300,1590;1HNMR(CDCl3)δ:0.92(d,6H),2.38–2.74(m,4H),3.13–3.78(m,2H).B.Caution!Becauseofthefoulodorofthemethylsulfidegi
7、venoff,thisprocedure,uptothemethanolquench,shouldbecarriedoutinahood.A2-L,three-necked,round-bottomedflaskisequippedwithamechanicalstirrer,heatingmantel,250-mLgraduatedadditionfunnel,andan8-in.,air-cooledrefluxcondenser(Westtype)toppedwithawater-cooleddistilla
