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Effect of Zn dust reduction of phenolic -OH group on other groups
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Alan Armstrong
Effect of Zn dust reduction of phenolic -OH group on other groups
I did some research for this question many years ago. Nisarg's answer prompted me to post an answer.
Nisarg's answer showed how nitrobenzene can be reduced to form different compounds but my answer focuses on some different compounds. Doing some literature surveys gave me results from very old books. All the reaction involves only zinc dust. I tried quoting but the majority of the terms/compound names are obsolete, so I have wrote them as points:
formanilide and its derivatives is reduced benzenenitrile and aniline (and its derivatives) as major products and other side products such as N-Methyldiphenylamine. Yield of nitrile 10-20% weight of initial formanilide.
N-alkyl-o-toluidine and N-alkyl-p-toluidine yields corresponding nitrile: yield 15-20%
methyl-α- and methyl-β-naphthalamine yield α- and β-naphthonitrile
xylidine and its isomers yields xylonitrile (prone to hydrolysis to yield xylic acid(isomeric carboxylic acid of xylene)) : yield 12%
Phenyl isothiocyanate and thiocarboanilide forms benzonitrile and some aniline.
References:
K.Gasiorowski and V.Merz, Journal of the Chemical Society, 1884
I did some research for this question many years ago. Nisarg's answer prompted me to post an answer.
Nisarg's answer showed how nitrobenzene can be reduced to form different compounds but my answer focuses on some different compounds. Doing some literature surveys gave me results from very old books. All the reaction involves only zinc dust. I tried quoting but the majority of the terms/compound names are obsolete, so I have wrote them as points:
formanilide and its derivatives is reduced benzenenitrile and aniline (and its derivatives) as major products and other side products such as N-Methyldiphenylamine. Yield of nitrile 10-20% weight of initial formanilide.
N-alkyl-o-toluidine and N-alkyl-p-toluidine yields corresponding nitrile: yield 15-20%
methyl-α- and methyl-β-naphthalamine yield α- and β-naphthonitrile
xylidine and its isomers yields xylonitrile (prone to hydrolysis to yield xylic acid(isomeric carboxylic acid of xylene)) : yield 12%
Phenyl isothiocyanate and thiocarboanilide forms benzonitrile and some aniline.
References:
K.Gasiorowski and V.Merz, Journal of the Chemical Society, 1884
@SRMaiti only zinc dust is used. No other catalyst/reagent used.More
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Out of the groups you mention $\ce{-NO2}$, $\ce{-CN}$ will most certainly react, $\ce{-CH3}$ and $\ce{-NH2}$ not so much and I am ambiguous about $\ce{-CONH2}$.
Although I said that $\ce{-CN}$ will react, I can't pin point the product which will form in a certain condition. But in case of $\ce{-NO2}$, I certainly can predict the product based on a list I complied a couple of years ago.
Out of the groups you mention $\ce{-NO2}$, $\ce{-CN}$ will most certainly react, $\ce{-CH3}$ and $\ce{-NH2}$ not so much and I am ambiguous about $\ce{-CONH2}$.
Although I said that $\ce{-CN}$ will react, I can't pin point the product which will form in a certain condition. But in case of $\ce{-NO2}$, I certainly can predict the product based on a list I complied a couple of years ago.
@Buraian Possibly condensation. My guess: The reaction creates nitroso and hydroxylamine products which then condense to azoxy and then ultimately to azo product.More
I did some research for this question many years ago. Nisarg's answer prompted me to post an answer.
Nisarg's answer showed how nitrobenzene can be reduced to form different compounds but my answer focuses on some different compounds. Doing some literature surveys gave me results from very old books. All the reaction involves only zinc dust. I tried quoting but the majority of the terms/compound names are obsolete, so I have wrote them as points:
References:
I did some research for this question many years ago. Nisarg's answer prompted me to post an answer.
Nisarg's answer showed how nitrobenzene can be reduced to form different compounds but my answer focuses on some different compounds. Doing some literature surveys gave me results from very old books. All the reaction involves only zinc dust. I tried quoting but the majority of the terms/compound names are obsolete, so I have wrote them as points:
References:
More
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Out of the groups you mention $\ce{-NO2}$, $\ce{-CN}$ will most certainly react, $\ce{-CH3}$ and $\ce{-NH2}$ not so much and I am ambiguous about $\ce{-CONH2}$.
Although I said that $\ce{-CN}$ will react, I can't pin point the product which will form in a certain condition. But in case of $\ce{-NO2}$, I certainly can predict the product based on a list I complied a couple of years ago.
The "List":
$$ \begin{array}{|ccc|} \hline \ce{Ph-NO2}&\xrightarrow[\ce{NH4Cl}]{\ce{Zn}}&\ce{Ph-NHOH}\\ \hline \ce{Ph-NO2}&\xrightarrow[\ce{NaOH}]{\ce{Zn}}&\ce{Ph-NH-NH-Ph}\\ \hline \ce{Ph-NO2}&\xrightarrow[\ce{NaOH}]{\ce{Zn+alcohol}}&\ce{Ph-N=N-Ph}\\ \hline \end{array} $$
References:
(1) Kamm, O. β-Phenylhydroxylamine". Organic Syntheses. ; Collective 1941, 1, 445.
(2) Bigelow, H. E.; Robinson, D. B. Azobenzene". Organic Syntheses. ; Collective 1955, 3, 103.
Out of the groups you mention $\ce{-NO2}$, $\ce{-CN}$ will most certainly react, $\ce{-CH3}$ and $\ce{-NH2}$ not so much and I am ambiguous about $\ce{-CONH2}$.
Although I said that $\ce{-CN}$ will react, I can't pin point the product which will form in a certain condition. But in case of $\ce{-NO2}$, I certainly can predict the product based on a list I complied a couple of years ago.
The "List":
$$\begin{array}{|ccc|}\hline\ce{Ph-NO2}&\xrightarrow[\ce{NH4Cl}]{\ce{Zn}}&\ce{Ph-NHOH}\\\hline\ce{Ph-NO2}&\xrightarrow[\ce{NaOH}]{\ce{Zn}}&\ce{Ph-NH-NH-Ph}\\\hline\ce{Ph-NO2}&\xrightarrow[\ce{NaOH}]{\ce{Zn+alcohol}}&\ce{Ph-N=N-Ph}\\\hline\end{array}$$
References:
(1) Kamm, O. β-Phenylhydroxylamine". Organic Syntheses. ; Collective 1941, 1, 445.
(2) Bigelow, H. E.; Robinson, D. B. Azobenzene". Organic Syntheses. ; Collective 1955, 3, 103.
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