Oxidation and reduction of aromatic compounds
25 real reactions from the literature: benzylic oxidation on alkylbenzenes and pyridines; benzylic halogenation on alkylbenzenes and thiophenes; nitro reduction on nitro compounds; and more. Each scheme shows starting materials, conditions and products, with the yield and reference where the source reports them.
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Benzylic oxidation: 2-methylpyridine with KMnO4; H2O, Δ gives picolinic acid (the arenecarboxylic acid).
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Benzylic halogenation: 4-bromotoluene (an alkylbenzene) with NBS; AIBN gives 4-bromobenzyl bromide (the benzylic halide). 100% yield.
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Nitro reduction: ethyl 4-nitrobenzoate (a nitro compound) with H2 (3 atm), PtO2; CH3CH2OH gives benzocaine (the aniline).
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Clemmensen: 1-(2-hydroxyphenyl)hexan-1-one (an aryl ketone) with mossy Zn(Hg); aq. HCl, CH3CH2OH, Δ gives 2-hexylphenol (the deoxygenated product).
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Birch reduction: benzoic acid (an acyl-deactivated arene) with 1) Na, NH3, CH3CH2OH; 2) aq. HCl gives 2,5-cyclohexadiene-1-carboxylic acid (the 1,4-cyclohexadiene).
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Benzylic oxidation: 2-chlorotoluene (an alkylbenzene) with 1) KMnO4, H2O; 2) HCl gives 2-chlorobenzoic acid (the arenecarboxylic acid).
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Benzylic halogenation: 3-methylthiophene with NBS; benzoyl peroxide, benzene, Δ gives 3-(bromomethyl)thiophene (the benzylic halide).
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Nitro reduction: 2-nitroaniline (a nitro compound) with Zn, CH3CH2OH; aq. NaOH, Δ gives o-phenylenediamine (the aniline).
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Clemmensen: 3-benzoylpropionic acid (an aryl ketone) with Zn(Hg); HCl, H2O; toluene, Δ gives 4-phenylbutyric acid (the deoxygenated product).
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Birch reduction: o-xylene (an alkylbenzene) with Na, NH3; CH3CH2OH, ether gives 1,2-dimethyl-1,4-cyclohexadiene.
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Benzylic oxidation: 4-nitrotoluene (an alkylbenzene) with Na2Cr2O7; aq. H2SO4, Δ gives 4-nitrobenzoic acid (the arenecarboxylic acid).
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Benzylic halogenation: o-xylene (an alkylbenzene) with Br2, (4 equiv.); hν gives o-bis(bromomethyl)benzene (the benzylic halide).
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Benzylic oxidation: chloro-(4-methylphenyl)mercury (an alkylbenzene) with 1) KMnO4; aq. NaOH, Δ; 2) HCl gives p-(chloromercuri)benzoic acid (the arenecarboxylic acid).
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Birch reduction: 2-ethoxynaphthalene with Na; CH3CH2OH, Δ gives 3-ethoxy-1,2-dihydronaphthalene (the 1,4-cyclohexadiene).
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Benzylic halogenation: p-xylene (an alkylbenzene) with Br2, hν; Δ gives 1,4-bis(bromomethyl)benzene (the benzylic halide).
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Benzylic halogenation: (3-bromopropyl)benzene (an alkylbenzene) with NBS, benzoyl peroxide; CCl4, Δ gives 1,3-dibromo-1-phenylpropane (the benzylic halide).
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Nitro reduction: 3-nitrobenzaldehyde dimethyl acetal (a nitro compound) with H2 (1000 psi); Ra(Ni); CH3OH gives 3-(dimethoxymethyl)aniline.
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Nitro reduction: 2-nitrobenzaldehyde (a nitro compound) with FeSO4, HCl; NH4OH, H2O; 90 °C gives 2-aminobenzaldehyde (the aniline).
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Nitro reduction: 1-methyl-2-nitro-4-propan-2-ylbenzene (a nitro compound) with H2 (1000 psi); Ra(Ni); CH3OH; 100 - 120 °C gives 2-amino-p-cymene (the aniline).
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Birch reduction: anisole with Li, (CH3)3OH; liq. NH3, THF gives 1-methoxycyclohexa-1,4-diene (the 1,4-cyclohexadiene).
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Benzylic halogenation: 4-chlorotoluene (an alkylbenzene) with Cl2, PCl5; hν, Δ gives 1-chloro-4-(chloromethyl)benzene (the benzylic halide).
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Nitro reduction: 2-nitrobiphenyl (a nitro compound) with H2 (25-50 psi), 5% Pd/C; CH3CH2OH gives 2-aminobiphenyl (the aniline).
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Benzylic halogenation: 2-nitrotoluene (an alkylbenzene) with NBS; benzoyl peroxide, CCl4, Δ gives alpha-bromo-2-nitrotoluene (the benzylic halide).
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Benzylic halogenation: an alkylbenzene gives the benzylic halide. 63 % yield.
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Clemmensen: 3-hydroxy-2-methoxybenzaldehyde (an aromatic aldehyde) with Zn(Hg); HCl, Δ gives 2-methoxy-3-methylphenol (the deoxygenated product).