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Chemistry234Chapter16ProblemSet
ElectrophilicAromaticSubstitution1) Predicttheproductanddrawthemechanismforelectrophilegenerationforeachofthe
followingreactions.
2) ExplainwhyreactionofbenzenewithBr2/FeBr3resultsintheproductbromobenzneinsteadof5,6-dibromo-1,3-cyclohexadiene.
3) Predicttheproductanddrawtheactiveelectrophileforeachreactionshownbelow.
Cl2FeCl3
HNO3
H2SO4
SO3
H2SO4
(a)
(b)
(c)
AlCl3(a)
(b)
(c)
Cl
AlCl3
Cl
AlCl3
Cl
O
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4) ExplainwhyeachofthefollowingsubstratesdonotundergoFreidel-Craftsreactions.
5) Arrangethefollowingbenzenesubstituentsinorderofreactivityinelectrophilicaromaticsubstitutionreactions.
6) Predictthemajorproductswhenthefollowingbenzenederivativesaretreatedto
nitrationconditions(HNO3/H2SO4).
7) Writethefullelectronpushingmechanismforthenitrationoftoluene.
NH2 NO2 N(CH3)3 NH
Ph PhCl
Ph
O
PhN
PhHN
OPh
HN Ph
SPh O
O
O
Br
NH2Br
NO2Cl
a.
b.
c.
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8) Predicttheproduct(s)wheneachofthefollowingbenzenederivativesistreatedtochloroethaneandAlCl3.
Br
NH2
Cl
OHCl
Cl
OH
Br
a.
b.
c.
d.
SO3H
NO2Cl
Cl
Br
Br
e.
f.
g.
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9) Predicttheproduct(s)whenthefollowingbenzenederivativesaresubjectedtoelectrophilicchlorinationconditions(Cl2,FeCl3).
10) Predicttheproduct(s)foreachofthefollowingreactions.
OH
NO2
NO2
O OH
Br
SO3H
a.
b.
c.
d.
Br O
OCH3
O
H3CO
OCH3
HO
Br NO2
Cl2
FeCl3
HNO3
H2SO4
SO3
H2SO4
SO3
H2SO4
a.
b.
c.
d.
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11) Predicttheproductforeachbenzeneside-chainmodificationreactionshownbelow.
12) Proposeasynthesisforeachofthefollowingcompoundsstartingwithbenzene.
a.
b.
c.
d.
KMnO4
H2CrO4
NBSlight
NO2 H2Pd/C
e. NO2 SnHCl
f.Zn(Hg)HCl
O
g.N2H2HO-
O
a. COOH
COOH
NO2
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b. NH2
Cl
c.
Cl Br
NO2
d.NO2
Cl
O
e. COOH
ClBr
NO2
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DiazoniumIonReactions13) Writeoutthesyntheticsequencetopreparephenolandacetanilide(Ph-NHCOCH3)from
benzene.
f.
Cl NO2
O
g.Br
O2N
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14) Providesynthesesforeachofthefollowingcompounds,freeofotherisomers.Yourstartingmaterialshouldbebenzeneineachcase.
Br
OH
a.
I Clb.
BrF
Br
c.
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NucleophilicAromaticSubstitution15) Foreachreactionshownbelow,determineifthereactionis(a)electrophilicaromatic
substitution,(b)NucleophilicAromaticSubstitution:Addition-Elimination,or(c)NucleophilicAromaticSubstitution:BenzyneMechanism.
NC
d.
ClNaOH350 °C
ClNaNH2
NH3
ClNaNH2
NH3
H3C
Cl
NaOH
NO2
ClHNO3H2SO4
Br
NO2
NO2 NaOCH3
a.
b.
c.
d.
e.
f.
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16) Showthefullelectronpushingmechanismforreaction15c.
17) Showthefullelectronpushingmechanismforreaction15d.
18) Explainwhythereactionshownbelowdoesnotoccur.
19) Considerthereactionshownbelow.Theoretically,therearethreepossibleproducts.Draw
eachoftheseproducts.Inrealityonlyoneoftheseproductsisformed.Whichoneistheobservedproduct?
Cl
NO2O2N
NaOHHeat
OH
NO2O2N
Cl
NO2
OCH3Cl
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20) Showtwomethodstosynthesizethemoleculeshownbelowstartingwithbenzene.Onerouteshouldusediazoniumionchemistrywhiletheotherrouteshouldnot.
21) ShowthereactionofphenolwithNaOH.
22) ShowthereactionofbenzoicacidwithNaOH.
23) Isphenolorbenzoicacidastrongeracid?Explain.
24) ShowthereactionofanilinewithHCl.
NO2
OH
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25) Rankthecompoundsineachsetbelowinorderofincreasingacidity.
26) Ranktheanilinederivativesbelowinorderofincreasingbasicity.
ChallengeProblems27) Writeamechanismforthefollowingreaction.
NH2 OHO
OH
O
OH
Br
(a)
OH(b)
OHNO2 OH OHO2N
NH2
O2N
NH2
O
NH2
O
NH2
H H
O
HCl
Cl
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28) PredictthemajorproductforthereactionofpyrrolewithBr2,FeBr3.Hint:useresonanceanalysisoftheintermediatetodeterminethepreferredregioselectivityofthereaction.
29) Showtheelectronpushingmechanismforthereactionshownbelow.
30) Substitutedpyridinesareknowntoundergonucleophilicaromaticsubstitutionviaanadditioneliminationmechanism.Predicttheproductandshowthemechanismforthereactionshownbelow.
HN Br2
FeBr3
OH
SO2NO2
NaHO
SO2
NO2
N Br
OH
