Advertisements
Advertisements
Questions
Write a short note on Hoffmann bromamide degradation.
Explain Hoffmann bromamide degradation reaction
Advertisements
Solution 1
(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:
Solution 2
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.
RELATED QUESTIONS
How is ethyl amine prepared from methyl iodide?
Identify the compounds 'A' and 'B' in the following equation:
Illustrate the following reaction giving suitable example in each case:Gabriel phthalimide synthesis
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 :
Write a short note on the following:
Hoffmann’s bromamide reaction
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:
\[\ce{CH3CH2Br ->[KCN] A ->[LiAlH4] B ->[HNO2][0^\circ C] C}\]
Give the structure of A, B and C in the following reaction:
\[\ce{C6H5NO2 ->[Fe/HCl] A ->[NaNO2 + HCl][273 K] B ->[H2O/H+][\Delta] C}\]
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
Write structures of compounds A and B in each of the following reactions:
Answer in one sentence.
Which amide does produce ethanamine by Hofmann bromamide degradation reaction?
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 Gabriel phthalimide synthesis.
Answer the following
Explain the ammonolysis of alkyl halides.
Mendius reaction is used to convert _____________
Write reactions to bring about the following conversions.
Acetamide to Ethylamine
Explain Hoffmann’s exhaustive alkylation with suitable reactions.
Explain the following reaction with a suitable example.
Hofmann elimination reaction
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 ____________.
Identify the product obtained, when benzamide is treated with bromine and aqueous sodium hydroxide.
Which of the following amines exhibits maximum degree of intermolecular hydrogen bonding?
What product is formed when \[\ce{R - C ≡ N}\] is hydrolysed?
Which of the following amines forms a clear solution when treated with benzene sulphonyl chloride and excess of potassium hydroxide?
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?
Amongst the given set of reactants, the most appropriate for preparing 2° amine is ______.
Hoffmann Bromamide Degradation reaction is shown by ______.
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?
What is the product when \[\ce{C6H5CH2NH2}\] reacts with \[\ce{HNO2}\]?
Identify A and B in the following reaction.
Write following conversions:
acetanilide `->` p-nitroaniline
How will you carry out the following conversion?
How will you carry out the following conversions?
Match the reactions given in Column I with the statements given in Column II.
| Column I | Column II | ||
| (i) | Ammonolysis | (a) | Amine with lesser number of carbon atoms |
| (ii) | Gabriel phthalimide synthesis | (b) | Detection test for primary amines. |
| (iii) | Hoffmann Bromamide reaction | (c) | Reaction of phthalimide with \[\ce{KOH}\] and \[\ce{R-X}\] |
| (iv) | Carbylamine reaction | (d) | Reaction of alkylhalides with \[\ce{NH3}\] |
Describe Gabriel's phthalimide synthesis. (Give reaction)
Account for the following:
Aniline cannot be prepared by the ammonolysis of chlorobenzene under normal conditions.
A primary amine is formed by an amide on treatment with bromine and alkali. The primary amine has
C6H5CONHCH3 can be converted into C6H5CH2NHCH3 by:-
When primary amines are treated with HCl, the product obtained is which of the following?
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?
The amine 'A' when treated with nitrous acid gives yellow oily substance. The amine A is ______.
Which of the following statement(s) is/are incorrect in case of Hofmann bromamide degradation?
What is the IUPAC name of \[\ce{(CH3)2 - N - CH3}\]?
Which of the following would not be a good choice for reducing nitrobenzene to aniline?
Write short note on the following:
Ammonolysis
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 notes on the following:
Ammonolysis
