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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
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:
Nitrobenzene to benzoic acid
Accomplish the following conversion:
Benzamide to toluene
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?
Give a plausible explanation for the following:
Why are amines less acidic than alcohols of comparable molecular masses?
Mention 'two' uses of propan-2-one.
Account for the following:
Gabriel phthalimide synthesis is not preferred for preparing aromatic primary amines.
Choose the most correct option.
Which of the following compounds will dissolve in aqueous NaOH after undergoing reaction with Hinsberg reagent?
Write reactions to bring about the following conversions.
Acetamide to methylamine
Explain the following reaction with a suitable example.
Hofmann elimination reaction
Alkyl cyanides on reduction by sodium and ethanol give primary amines. This reaction is called as ____________.
Identify the product obtained when benzyl chloride undergoes ammonolysis in presence of excess ammonia followed by the reaction with two moles of methyl iodide.
Which of the following amines exhibits maximum degree of intermolecular hydrogen bonding?
Identify the major product (B).
____________ can be prepared exclusively by Gabriel phthalimide synthesis.
What product is formed when \[\ce{R - C ≡ N}\] is hydrolysed?
\[\ce{CH3-CN ->[Na/C2H5OH]}\]
The product formed is ____________.
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?
The reduction of alkyl cyanide with sodium and ethanol to give primary amines is, ____________.
Identify the INCORRECT statement regarding Hofmann bromamide reaction.
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?
Nitro compounds are reduced by iron scrap and hydrochloric acid to yield one of the following compounds:
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:
In order to prepare a 1° amine from an alkyl halide with simultaneous addition of one \[\ce{CH2}\] group in the carbon chain, the reagent used as source of nitrogen is ______.
The source of nitrogen in Gabriel synthesis of amines is ______.
Amongst the given set of reactants, the most appropriate for preparing 2° amine 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
Under which of the following reaction conditions, aniline gives p-nitro derivative as the major product?
(i) Acetyl chloride/pyridine followed by reaction with conc.\[\ce{H2SO4 }\] + conc. \[\ce{HNO3}\].
(ii) Acetic anyhdride/pyridine followed by conc.\[\ce{H2SO4}\] + conc.\[\ce{HNO3}\].
(iii) Dil. HCl followed by reaction with conc.\[\ce{H2SO4}\] + conc.\[\ce{HNO3}\].
(iv) Reaction with conc.\[\ce{HNO3}\] + conc.\[\ce{H2 SO4}\].
What is the best reagent to convert nitrile to primary amine?
Suggest a route by which the following conversion can be accomplished.
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.
The compound X is which of the following?
\[\ce{CH3CN ->[Na + C2H5OH] x}\]
Acetamide and ethyl amide can be distinguished by reacting with.
When primary amines are treated with HCl, the product obtained is which of the following?
Which of the following CANNOT be prepared by ammonolysis of alkyl halide?
The amine 'A' when treated with nitrous acid gives yellow oily substance. The amine A is ______.
Write a short note on the following:
Ammonolysis
Write a short note on the following:
Ammonolysis
Write a short note on Ammonolysis.
Write a short note on the following:
Ammonolysis
