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प्रश्न
Write a short note on Hoffmann bromamide degradation.
Explain Hoffmann bromamide degradation reaction
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
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 :
Accomplish the following conversion:
Benzyl chloride to 2-phenylethanamine
Accomplish the following conversion:
Benzamide to toluene
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:
\[\ce{C6H5NO2 ->[Fe/HCl] A ->[NaNO2 + HCl][273 K] B ->[H2O/H+][\Delta] C}\]
Why cannot aromatic primary amines be prepared by Gabriel phthalimide synthesis?
Write the reactions of aromatic with nitrous acid.
Give plausible explanation for each of the following :
Why are amines less acidic than alcohols of comparable molecular masses?
Explain the mechanism of action of hydroiodic acid on 3-methylbutan-2-ol.
Mention 'two' uses of propan-2-one.
Arrange the following in the increasing order of their pKb values:
C6H5NH2, C2H5NH2, C6H5NHCH3
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:
Choose the most correct option.
Which of the following compounds will dissolve in aqueous NaOH after undergoing reaction with Hinsberg reagent?
Answer the following
Identify A and B in the following reactions.
\[\ce{C6H5CH2Br->[alco.][KCN]A ->[Na/ethanol]B.}\]
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 _____________
Why cannot aniline be prepared by Gabriel phthalimide synthesis?
Acetamide on reduction using Na/C2H5OH gives ____________.
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.
Identify the major product (B).
____________ can be prepared exclusively by Gabriel phthalimide synthesis.
Which nitrogen containing compound amongst the following would undergo Mendius reduction to furnish primary amine \[\ce{(R - NH2)}\]?
The reduction of alkyl cyanide with sodium and ethanol to give primary amines is, ____________.
Identify the INCORRECT statement regarding Hofmann bromamide reaction.
Which of the following reagents is used in Mendius reduction reaction of alkyl cyanide?
Which of the following amines cannot be prepared by Gabriel phthalimide synthesis?
Given below are two statements labelled as Assertion (A) and Reason (R).
Assertion (A): Alkyl halides are insoluble in water.
Reason (R): Alkyl halides have halogen attached to sp3 hybrid carbon.
Select the most appropriate answer from the options given below:
The best reagent for converting, 2-phenylpropanamide into 1- phenylethanamine 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?
The reagents that can be used to convert benzenediazonium chloride to benzene are:
(i) \[\ce{SnCl2/HCl}\]
(ii) \[\ce{CH3CH2OH}\]
(iii) \[\ce{H3PO2}\]
(iv) \[\ce{LiAlH4}\]
What is the best reagent to convert nitrile to primary amine?
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.
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)
Reduction of nitro alkanes yields which compound?
Acetamide and ethyl amide can be distinguished by reacting with.
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.
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?
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 ______.
What is the IUPAC name of \[\ce{(CH3)2 - N - CH3}\]?
Write a 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 a short note on the following:
Ammonolysis.
