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प्रश्न
Write a short note on the following:
Hoffmann’s bromamide reaction
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उत्तर
Hoffmann developed a method for preparation of primary amines by treating an amide with bromine in an aqueous or ethanolic solution of sodium hydroxide. In this degradation reaction, migration of an alkyl or aryl group takes place from carbonyl carbon of the amide to the nitrogen atom. The amine so formed contains one carbon less than that present in the amide.
\[\begin{array}{cc}
\ce{O}\phantom{.............................................................}\\
||\phantom{.............................................................}\\
\ce{R - C - NH2 + Br2 + 4NaOH -> R - NH2 + Na2CO3 + 2NaBr + 2H2O}
\end{array}\]
संबंधित प्रश्न
How is ethyl amine prepared from methyl iodide?
How are propan-1-amine and propan-2-amine prepared from oxime?
How do you convert the following: C6H5CONH2 to C6H5NH2
Give the structures of A, B and C in the following reactions :
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:
\[\ce{C6H5NO2 ->[Fe/HCl] A ->[NaNO2 + HCl][273 K] B ->[H2O/H+][\Delta] C}\]
Write the reaction of aromatic primary amine with nitrous acid.
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.
Choose the most correct option.
Which of the following compounds will dissolve in aqueous NaOH after undergoing reaction with Hinsberg reagent?
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
Explain Gabriel phthalimide synthesis.
Mendius reaction is used to convert _____________
Explain Hoffmann’s exhaustive alkylation with suitable reactions.
Write reactions for the preparation of ethanamine using 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 ____________.
Alkyl cyanides on reduction by sodium and ethanol give primary amines. This reaction is called as ____________.
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.
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 of the following reactions is appropriate for converting benzamide to aniline?
Identify 'A' and 'B' in the following conversions.
\[\ce{CH3 - I ->[Alc. KCN][\Delta] A ->[Na/C2H5OH] B}\]
Identify the INCORRECT statement regarding Hofmann bromamide reaction.
Which of the following amines cannot be prepared by Gabriel phthalimide synthesis?
Identify product B in the following reaction.
\[\ce{Aniline ->[NaNO2][HCl] A ->[KI] B}\]
Which of the following compounds is obtained when quaternary ammonium hydroxide is strongly heated?
Which of the following does NOT give carbylamine test?
For producing amines, the reaction of nitro compounds with iron scrap is preferred because:
Quaternary ammonium salt is formed:
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:
Amongst the following, the strongest base in aqueous medium is ______.
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 ______.
The best reagent for converting 2–phenylpropanamide into 2-phenylpropanamine is ______.
The best reagent for converting, 2-phenylpropanamide into 1- phenylethanamine is ______.
Among the following amines, the strongest Brönsted base is:
Reduction of nitrobenzene by which of the following reagent gives aniline?
(i) \[\ce{Sn/HCl}\]
(ii) \[\ce{Fe/HCl}\]
(iii) \[\ce{H2 - Pd}\]
(iv) \[\ce{Sn/NH4OH}\]
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 product when \[\ce{C6H5CH2NH2}\] reacts with \[\ce{HNO2}\]?
Identify A and B in the following reaction.
Write following conversions:
nitrobenzene `->` acetanilide
Write following conversions:
acetanilide `->` p-nitroaniline
The compound X is which of the following?
\[\ce{CH3CN ->[Na + C2H5OH] x}\]
In the given reaction what is the X?
\[\begin{array}{cc}
\ce{O}\phantom{.......................}\\
||\phantom{.......................}\\
\phantom{}\ce{R - C - OH <-[H3O] Χ ->[H] RCH2NH2}
\end{array}\]
Which of the following compound is expected to be most basic?
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?
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?
Methyl amine on reaction with chloroform in the presence of NaOH gives ______.
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 the name of the product formed by the action of LiAlH4/ether on acetamide.
Write short note on the following:
Ammonolysis
Write short notes on the following:
Ammonolysis
Write a short note on the following:
Ammonolysis
