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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:
Write the chemical equation involved in the following reaction:
Hoffmann-bromamide degradation reaction
How do you convert the following: C6H5CONH2 to C6H5NH2
Write a short note on the following:
Hoffmann’s bromamide reaction
Accomplish the following conversion:
Nitrobenzene to benzoic acid
Accomplish the following conversion:
Benzyl chloride to 2-phenylethanamine
Give the structure of A, B and C in the following reaction:
\[\ce{CH3CH2I ->[NaCN] A ->[OH-][Partial hydrolysis] B ->[NaOH + Br2] C}\]
Why cannot aromatic primary amines be prepared by Gabriel phthalimide synthesis?
Mention 'two' uses of propan-2-one.
Identify 'A' and 'B' in the following reaction and rewrite the complete reaction :
Account for the following:
Gabriel phthalimide synthesis is not preferred for preparing aromatic primary amines.
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.
The following amines is the product of Gabriel phthalimide synthesis.
Mendius reaction is used to convert _____________
Write reactions to bring about the following conversions.
Acetamide to Ethylamine
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?
\[\ce{Acetonitrile ->[Na/alcohol] A ->[NaNO2/dil.HCI] B}\]
Acetamide on reduction using Na/C2H5OH gives ____________.
The end product C of the following reaction is
\[\ce{C2H5NH2 ->[HNO2] A ->[PCl5] B ->[NH3][Alcohol] C}\]
____________ can be prepared exclusively by Gabriel phthalimide synthesis.
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?
For producing amines, the reaction of nitro compounds with iron scrap is preferred because:
Amongst the following, the strongest base in aqueous medium is ______.
Which of the following reagents would not be a good choice for reducing an aryl nitro compound to an amine?
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 ______.
Amongst the given set of reactants, the most appropriate for preparing 2° amine is ______.
The best reagent for converting 2–phenylpropanamide into 2-phenylpropanamine is ______.
The best reagent for converting, 2-phenylpropanamide into 1- phenylethanamine is ______.
Best method for preparing primary amines from alkyl halides without changing the number of carbon atoms in the chain 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) \[\ce{LiAlH4}\]
Identify A and B in the following reaction.
How will you carry out the following conversions?
Assertion: Only a small amount of \[\ce{HCl}\] is required in the reduction of nitro compounds with iron scrap and \[\ce{HCl}\] in the presence of steam.
Reason: \[\ce{FeCl2}\] formed gets hydrolysed to release \[\ce{HCl}\] during the reaction.
Ethylamine can be prepared by the action of bromine and caustic potash on which compound?
Reduction of nitro alkanes yields which compound?
In the given reaction what is the X?
\[\begin{array}{cc}
\ce{O}\phantom{.......................}\\
||\phantom{.......................}\\
\phantom{}\ce{R - C - OH <-[H3O] Χ ->[H] RCH2NH2}
\end{array}\]
When primary amines are treated with HCl, the product obtained is which of the following?
Which of the following reaction DOES NOT involve Hoffmann bromamide degradation?
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 ______.
Which of the following statement(s) is/are incorrect in case of Hofmann bromamide degradation?
Write short note on the following:
Ammonolysis
Identify A and B in the following reaction.
\[\ce{C6H5CH2Br ->[Alco.][KCN] A ->[Na/Ethanol][reduction] B}\]
Write a short note on the following:
Ammonolysis
Write short note on the following.
Ammonolysis.
