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प्रश्न
Write a short note on Hoffmann bromamide degradation.
Explain Hoffmann bromamide degradation reaction
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उत्तर १
(a)Hoffmann Bromanide degradation
(1) The conversion of amides into amine in presence of bromine and alkali is known on Hoffmann degradation of amides.
(2) An important characteristic of this reaction is that on amine with one carbon less than those in the amide is formed.
(3) This reaction is an example of molecular rearrangement and involves migration of an alkyl or aryl group from the carbonyl carbon to this adjacent nitrogen atom.
Example:
उत्तर २
Hoffmann bromamide reaction:
a) Primary amine can be prepared by reaction of amide with bromine and aqueous or
alcoholic sodium hydroxide.
eg. Ethanamine is prepared by reaction of propanamide with bromine and aqueous or
alcoholic sodium hydroxide.
b) This reaction is known as Hoffmann bromamide degradation. It involves molecular
rearrangement. An alkyl or aryl group migrates from the carbonyl carbon to the
adjacent nitrogen atom.
c) This reaction is useful for decreasing the length of carbon chain by one carbon atom.
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 :
Give the structures of A, B and C in the following reactions :
Give the structure of A, B and C in the following reaction:
\[\ce{CH3CH2I ->[NaCN] A ->[OH-][Partial hydrolysis] B ->[NaOH + Br2] C}\]
Give the structures of A, B and C in the following reaction:
\[\ce{C6H5NO2 ->[Fe/HCl] A ->[HNO2][273 K] B ->[C6H5OH] C}\]
Give a plausible explanation for the following:
Why are amines less acidic than alcohols of comparable molecular masses?
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 :
Write structures of compounds A and B in each of 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.
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
Explain Hoffmann’s exhaustive alkylation with suitable reactions.
Why cannot aniline be prepared by Gabriel phthalimide synthesis?
Identify compound 'B' in following series of reactions?
\[\ce{Acetonitrile ->[Na/alcohol] A ->[NaNO2/dil.HCI] B}\]
Identify the product 'A' in the following reaction.
\[\ce{Aniline ->[(CH3CO)2O][Pyridine] A}\]
Alkyl cyanides on reduction by sodium and ethanol give primary amines. This reaction is called as ____________.
What is the molar mass of the amine formed when acetamide undergoes Hofmann bromamide degradation?
\[\ce{CH3-CN ->[Na/C2H5OH]}\]
The product formed is ____________.
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?
Identify the product obtained when benzamide is treated with bromine and aqueous sodium hydroxide?
Which of the following reagents is used in Mendius reduction reaction of alkyl cyanide?
Which of the following reagents is used in Hofmann's elimination reaction of amines?
The source of nitrogen in Gabriel synthesis of amines is ______.
Amongst the given set of reactants, the most appropriate for preparing 2° amine is ______.
The best reagent for converting, 2-phenylpropanamide into 1- phenylethanamine is ______.
Hoffmann Bromamide Degradation reaction is shown by ______.
Best method for preparing primary amines from alkyl halides without changing the number of carbon atoms in the chain is ______.
Which of the following compounds is the weakest Brönsted base?
Which of the following amines can be prepared by Gabriel synthesis.
(i) Isobutyl amine
(ii) 2-Phenylethylamine
(iii) N-methylbenzylamine
(iv) Aniline
Which of the following reactions are correct?
(i)
(ii)
(iii)
(iv)
What is the product when \[\ce{C6H5CH2NH2}\] reacts with \[\ce{HNO2}\]?
How will you carry out the following conversion?
How will you carry out the following conversions?
Assertion: Hoffmann’s bromamide reaction is given by primary amines.
Reason: Primary amines are more basic than secondary amines.
Describe Gabriel's phthalimide synthesis. (Give reaction)
The compound X is which of the following?
\[\ce{CH3CN ->[Na + C2H5OH] x}\]
Which of the following CANNOT be prepared by ammonolysis of alkyl halide?
Which of the following compound gives pink colour on reaction with phthalic anhydride in cone. H2SO4 followed by treatment with NaOH?
Methyl amine on reaction with chloroform in the presence of NaOH gives ______.
Which of the following amines can be prepared by Gabriel phthalimide reaction?
- Phenyl methenamine
- N, N - Dimethylaniline
- N - Methyl aniline
- Benzenamine
Choose the correct order of the basic nature of the above amines.
The amine 'A' when treated with nitrous acid gives yellow oily substance. The amine A is ______.
What is the IUPAC name of \[\ce{(CH3)2 - N - CH3}\]?
Write a short note on the following:
Ammonolysis
Write the name of reduction product formed when ethyl cyanide is treated with sodium and alcohol.
Write short note on the following:
Ammonolysis
Write a short note on Ammonolysis.
