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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
How is ethyl amine prepared from methyl iodide?
Illustrate the following reaction giving suitable example in each case:Gabriel phthalimide synthesis
How do you convert the following: Ethanenitrile to ethanamine
Give the structures of A, B and C in the following reactions :
Give the structures of A, B and C in the following reactions :
Accomplish the following conversion:
Benzamide to toluene
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 structure of A, B and C in the following reaction:
\[\ce{C6H5N2Cl ->[CuCN] A ->[H2O/H+] B ->[NH3][\Delta] C}\]
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.
Give a plausible explanation for the following:
Why are amines less acidic than alcohols of comparable molecular masses?
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.
Write structures of compounds A and B in each of the following reactions:
Answer the following
Explain Gabriel phthalimide synthesis.
Write reactions to prepare ethanamine from Acetonitrile.
Write reactions for the preparation of ethanamine using Gabriel phthalimide synthesis.
The end product C of the following reaction is
\[\ce{C2H5NH2 ->[HNO2] A ->[PCl5] B ->[NH3][Alcohol] C}\]
Identify the major product (B).
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 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?
Identify the product obtained when benzamide is treated with bromine and aqueous sodium hydroxide?
Identify 'A' and 'B' in the following conversions.
\[\ce{CH3 - I ->[Alc. KCN][\Delta] A ->[Na/C2H5OH] B}\]
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:
For producing amines, the reaction of nitro compounds with iron scrap is preferred because:
The source of nitrogen in Gabriel synthesis of amines is ______.
The best reagent for converting, 2-phenylpropanamide into 1- phenylethanamine is ______.
Which of the following compounds is the weakest Brönsted base?
What is the product when \[\ce{C6H5CH2NH2}\] reacts with \[\ce{HNO2}\]?
Suggest a route by which the following conversion can be accomplished.
How will you bring out the following conversion?
How will you carry out the following conversion?
How will you carry out the following conversions?
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.
Assertion: Aromatic 1° amines can be prepared by Gabriel Phthalimide Synthesis.
Reason: Aryl halides undergo nucleophilic substitution with anion formed by phthalimide.
Describe Gabriel's phthalimide synthesis. (Give reaction)
A primary amine is formed by an amide on treatment with bromine and alkali. The primary amine has
The compound X is which of the following?
\[\ce{CH3CN ->[Na + C2H5OH] x}\]
Acetamide and ethyl amide can be distinguished by reacting with.
Which of the following compound gives pink colour on reaction with phthalic anhydride in cone. H2SO4 followed by treatment with NaOH?
Which of the following reaction DOES NOT involve Hoffmann bromamide degradation?
- 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 the compo ds A and B in the following reactions:
\[\ce{A ->[Nitrating mixture] B ->[(i) Sn/cone. HCI][(ii) NaOH] Aniline}\]
Identify A and B in the following reaction.
\[\ce{C6H5CH2Br ->[Alco.][KCN] A ->[Na/Ethanol][reduction] B}\]
Write the name of reduction product formed when ethyl cyanide is treated with sodium and alcohol.
Write a short note on Ammonolysis.
Write short note on the following.
Ammonolysis.
Write short notes on the following:
Ammonolysis
