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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
Identify the compounds 'A' and 'B' in the following equation:
An aromatic compound 'A' of molecular formula C7H7ON undergoes a series of reactions as shown below. Write the structures of A, B, C, D and E in the following reactions :
How do you convert the following: Ethanenitrile to ethanamine
Give the structures of A, B and C in the following reactions :
Accomplish the following conversion:
Benzyl chloride to 2-phenylethanamine
Give the structure of A, B and C in the following reaction:
\[\ce{C6H5N2Cl ->[CuCN] A ->[H2O/H+] B ->[NH3][\Delta] C}\]
Give the structure of A, B and C in the following reaction:
\[\ce{CH3CH2Br ->[KCN] A ->[LiAlH4] B ->[HNO2][0^\circ C] C}\]
Give the structure of A, B and C in the following reaction:
\[\ce{C6H5NO2 ->[Fe/HCl] A ->[NaNO2 + HCl][273 K] B ->[H2O/H+][\Delta] C}\]
Write the reaction of aliphatic primary amine with nitrous acid.
Identify 'A' and 'B' in the following reaction and rewrite the complete reaction :
Arrange the following in the increasing order of their pKb values:
C6H5NH2, C2H5NH2, C6H5NHCH3
Give the structures of A, B and C in the following reactions :
Give the structures of A, B and C in the following reactions :
Choose the most correct option.
Which of the following compounds will dissolve in aqueous NaOH after undergoing reaction with Hinsberg reagent?
Answer the following
Write a reaction to convert acetic acid into methylamine.
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.
Write the order of reactivity of alkyl halides with ammonia.
Write reactions to bring about the following conversions.
Acetamide to methylamine
Identify the product 'A' in the following reaction.
\[\ce{Aniline ->[(CH3CO)2O][Pyridine] A}\]
The end product C of the following reaction is
\[\ce{C2H5NH2 ->[HNO2] A ->[PCl5] B ->[NH3][Alcohol] C}\]
Identify the product obtained, when benzamide is treated with bromine and aqueous sodium hydroxide.
____________ can be prepared exclusively by Gabriel phthalimide synthesis.
Identify the product obtained when benzamide is treated with bromine and aqueous sodium hydroxide?
The reduction of alkyl cyanide with sodium and ethanol to give primary amines is, ____________.
In aqueous phase the order of basic strength of alkylamine is ______.
Which of the following reagents is used in Mendius reduction reaction of alkyl cyanide?
Identify product B in the following reaction.
\[\ce{Aniline ->[NaNO2][HCl] A ->[KI] B}\]
Which of the following reagents is used in Hofmann's elimination reaction of amines?
Which of the following does NOT give carbylamine test?
Which of the following reactions does NOT yield an amine?
Nitro compounds are reduced by iron scrap and hydrochloric acid to yield one of the following compounds:
Quaternary ammonium salt is formed:
Benzylamine may be alkylated as shown in the following equation:
\[\ce{C6H5CH2NH2 + R - X -> C6H5CH2NHR}\]
Which of the following alkylhalides is best suited for this reaction through SN1 mechanism?
The source of nitrogen in Gabriel synthesis of amines is ______.
The best reagent for converting 2–phenylpropanamide into 2-phenylpropanamine is ______.
The best reagent for converting, 2-phenylpropanamide into 1- phenylethanamine is ______.
Among the following amines, the strongest Brönsted base is:
Which of the following methods of preparation of amines will give same number of carbon atoms in the chain of amines as in the reactant?
Which of the following reactions are correct?
(i)
(ii)
(iii)
(iv)
Suggest a route by which the following conversion can be accomplished.
Write following conversions:
acetanilide `->` p-nitroaniline
How will you bring out the following conversion?
How will you carry out the following conversions?
Assertion: Aromatic 1° amines can be prepared by Gabriel Phthalimide Synthesis.
Reason: Aryl halides undergo nucleophilic substitution with anion formed by phthalimide.
In the given reaction what is the X?
\[\begin{array}{cc}
\ce{O}\phantom{.......................}\\
||\phantom{.......................}\\
\phantom{}\ce{R - C - OH <-[H3O] Χ ->[H] RCH2NH2}
\end{array}\]
C6H5CONHCH3 can be converted into C6H5CH2NHCH3 by:-
Give reasons for the following:
Ammonolysis of alkyl halides is not a good method to prepare pure primary amines.
Methyl amine on reaction with chloroform in the presence of NaOH gives ______.
- Phenyl methenamine
- N, N - Dimethylaniline
- N - Methyl aniline
- Benzenamine
Choose the correct order of the basic nature of the above amines.
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 the name of reduction product formed when ethyl cyanide is treated with sodium and alcohol.
Assertion: Amimonolysis of alkyl halides involves the reaction between alkyl halides and alcoholic ammonia.
Reason: Ammonolysis of alkyl halides produces secondary amines only.
Write short notes on the following:
Ammonolysis
