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प्रश्न
Write a short note on the following:
Hoffmann’s bromamide reaction
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उत्तर
Hoffmann developed a method for preparation of primary amines by treating an amide with bromine in an aqueous or ethanolic solution of sodium hydroxide. In this degradation reaction, migration of an alkyl or aryl group takes place from carbonyl carbon of the amide to the nitrogen atom. The amine so formed contains one carbon less than that present in the amide.
\[\begin{array}{cc}
\ce{O}\phantom{.............................................................}\\
||\phantom{.............................................................}\\
\ce{R - C - NH2 + Br2 + 4NaOH -> R - NH2 + Na2CO3 + 2NaBr + 2H2O}
\end{array}\]
संबंधित प्रश्न
How is ethyl amine prepared from methyl iodide?
Write a short note on Hoffmann bromamide degradation.
How do you convert the following: Ethanenitrile to ethanamine
Give the structures of A, B and C in the following reactions :
Give the structure of A, B and C in the following reaction:
\[\ce{CH3CH2Br ->[KCN] A ->[LiAlH4] B ->[HNO2][0^\circ C] C}\]
Why cannot aromatic primary amines be prepared by Gabriel phthalimide synthesis?
Write the reaction of aromatic primary amine with nitrous acid.
Write the reaction of aliphatic primary amine with nitrous acid.
Mention 'two' uses of propan-2-one.
Identify 'A' and 'B' in the following reaction and rewrite the complete reaction :
Give the structures of A, B and C in the following reactions :
Give the structures of A, B and C in the following reactions :
Account for the following:
Gabriel phthalimide synthesis is not preferred for preparing aromatic primary amines.
Choose the most correct option.
Which of the following compounds will dissolve in aqueous NaOH after undergoing reaction with Hinsberg reagent?
Answer in one sentence.
Predict the product of the following reaction.
\[\ce{Nitrobenzene ->[Sn/conc.HCl]?}\]
Answer the following
Identify A and B in the following reactions.
\[\ce{C6H5CH2Br->[alco.][KCN]A ->[Na/ethanol]B.}\]
Answer the following
Explain the ammonolysis of alkyl halides.
Write reactions to prepare ethanamine from Acetonitrile.
Mendius reaction is used to convert _____________
Name the process of breaking C-X bond by ammonia in preparation of amines.
Explain Hoffmann’s exhaustive alkylation with suitable reactions.
Identify the product obtained, when benzamide is treated with bromine and aqueous sodium hydroxide.
____________ can be prepared exclusively by Gabriel phthalimide synthesis.
Which nitrogen containing compound amongst the following would undergo Mendius reduction to furnish primary amine \[\ce{(R - NH2)}\]?
Which of the following reactions is appropriate for converting benzamide to aniline?
Which of the following amines forms a clear solution when treated with benzene sulphonyl chloride and excess of potassium hydroxide?
The reduction of alkyl cyanide with sodium and ethanol to give primary amines is, ____________.
Identify the INCORRECT statement regarding Hofmann bromamide reaction.
In aqueous phase the order of basic strength of alkylamine is ______.
Identify product B in the following reaction.
\[\ce{Aniline ->[NaNO2][HCl] A ->[KI] B}\]
Quaternary ammonium salt is formed:
Amongst the following, the strongest base in aqueous medium is ______.
Amongst the given set of reactants, the most appropriate for preparing 2° amine is ______.
The best reagent for converting 2–phenylpropanamide into 2-phenylpropanamine is ______.
Hoffmann Bromamide Degradation reaction is shown by ______.
Reduction of aromatic nitro compounds using \[\ce{Fe}\] and \[\ce{HCl}\] gives ______.
Which of the following compounds is the weakest Brönsted base?
Among the following amines, the strongest Brönsted base is:
Reduction of nitrobenzene by which of the following reagent gives aniline?
(i) \[\ce{Sn/HCl}\]
(ii) \[\ce{Fe/HCl}\]
(iii) \[\ce{H2 - Pd}\]
(iv) \[\ce{Sn/NH4OH}\]
Which of the following amines can be prepared by Gabriel synthesis.
(i) Isobutyl amine
(ii) 2-Phenylethylamine
(iii) N-methylbenzylamine
(iv) Aniline
What is the product when \[\ce{C6H5CH2NH2}\] reacts with \[\ce{HNO2}\]?
What is the best reagent to convert nitrile to primary amine?
Suggest a route by which the following conversion can be accomplished.
Write following conversions:
nitrobenzene `->` acetanilide
Write following conversions:
acetanilide `->` p-nitroaniline
How will you carry out the following conversions?
Assertion: Only a small amount of \[\ce{HCl}\] is required in the reduction of nitro compounds with iron scrap and \[\ce{HCl}\] in the presence of steam.
Reason: \[\ce{FeCl2}\] formed gets hydrolysed to release \[\ce{HCl}\] during the reaction.
The compound X is which of the following?
\[\ce{CH3CN ->[Na + C2H5OH] x}\]
Ethylamine can be prepared by the action of bromine and caustic potash on which compound?
Reduction of nitro alkanes yields which compound?
C6H5CONHCH3 can be converted into C6H5CH2NHCH3 by:-
When primary amines are treated with HCl, the product obtained is which of the following?
Give reasons for the following:
Ammonolysis of alkyl halides is not a good method to prepare pure primary amines.
Which of the following reaction DOES NOT involve Hoffmann bromamide degradation?
Which of the following statement(s) is/are incorrect in case of Hofmann bromamide degradation?
What is the IUPAC name of \[\ce{(CH3)2 - N - CH3}\]?
Identify the product ‘C’ in the following reaction.
\[\ce{Aniline ->[(CH3CH)2O][Pyridine] A ->[Br2][CH3COOH] B ->[H^+ or OH^-] C}\]
Write the name of the product formed by the action of LiAlH4/ether on acetamide.
Identify the compo ds A and B in the following reactions:
\[\ce{A ->[Nitrating mixture] B ->[(i) Sn/cone. HCI][(ii) NaOH] Aniline}\]
Write short note on the following:
Ammonolysis
Identify A and B in the following reaction.
\[\ce{C6H5CH2Br ->[Alco.][KCN] A ->[Na/Ethanol][reduction] B}\]
Write a short note on the following:
Ammonolysis
Write short note on the following.
Ammonolysis.
Write a short note on Ammonolysis.
Assertion: Amimonolysis of alkyl halides involves the reaction between alkyl halides and alcoholic ammonia.
Reason: Ammonolysis of alkyl halides produces secondary amines only.
