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प्रश्न
Write the chemical equation involved in the following reaction:
Hoffmann-bromamide degradation reaction
Illustrate the following reaction giving a suitable example in the case:
Hoffmann bromamide degradation reaction
Write the reactions involved in Hofmann bromamide degradation reaction
Write the chemical equation involved in Hoffmann Bromamide degradation for acetamide.
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उत्तर १
- Primary amine can be prepared by reaction of the amide with bromine and aqueous or alcoholic sodium hydroxide. 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.
- This reaction is useful for decreasing the length of carbon chain by one carbon atom.
\[\ce{CH3 - CO - NH2 + 4NaOH + Br2 ->CH3 - NH2 + Na2CO3 + 2NaBr + 2H2O}\]
उत्तर २
\[\ce{R - CO - NH2 + 4NaOH + Br2 ->R - CH2 - NH2 + Na2CO3 + 2NaBr + 2H2O}\]
\[\ce{CH3 - CH2 - CO - NH2 + 4NaOH + 2NaBr + 2H2O->CH3 - CH2 - NH2 + Na2CO3 + 2NaBr + 2H2O}\]
APPEARS IN
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 :
Write a short note on the following:
Hoffmann’s bromamide reaction
Accomplish the following conversion:
Benzyl chloride to 2-phenylethanamine
Accomplish the following conversion:
Benzamide to toluene
Give the structures of A, B and C in the following reaction:
\[\ce{C6H5NO2 ->[Fe/HCl] A ->[HNO2][273 K] B ->[C6H5OH] C}\]
Give a plausible explanation for 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.
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.
The following amines is the product of Gabriel phthalimide synthesis.
Name the process of breaking C-X bond by ammonia in preparation of amines.
Write reactions to bring about the following conversions.
Acetamide to Ethylamine
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 ____________.
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.
Which of the following reactions is appropriate for converting benzamide to aniline?
The reduction of alkyl cyanide with sodium and ethanol to give primary amines is, ____________.
In aqueous phase the order of basic strength of alkylamine is ______.
Which of the following amines cannot be prepared by Gabriel phthalimide synthesis?
Which of the following reagents is used in Hofmann's elimination reaction of amines?
Which of the following reactions does NOT yield an amine?
Which of the following reagents would not be a good choice for reducing an aryl nitro compound to an amine?
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:
The reagents that can be used to convert benzenediazonium chloride to benzene are:
(i) \[\ce{SnCl2/HCl}\]
(ii) \[\ce{CH3CH2OH}\]
(iii) \[\ce{H3PO2}\]
(iv) \[\ce{LiAlH4}\]
Which of the following amines can be prepared by Gabriel synthesis.
(i) Isobutyl amine
(ii) 2-Phenylethylamine
(iii) N-methylbenzylamine
(iv) Aniline
Which of the following reactions are correct?
(i)
(ii)
(iii)
(iv)
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?
Write following conversions:
acetanilide `->` p-nitroaniline
How will you carry out the following conversion?
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 \[\ce{NH3}\] |
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)
Account for the following:
Aniline cannot be prepared by the ammonolysis of chlorobenzene under normal conditions.
The Gabriels' phthalimide synthesis is used in the synthesis of
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?
\[\begin{array}{cc}
\ce{O}\phantom{.......................}\\
||\phantom{.......................}\\
\phantom{}\ce{R - C - OH <-[H3O] Χ ->[H] RCH2NH2}
\end{array}\]
Which of the following compound is expected to be most basic?
C6H5CONHCH3 can be converted into C6H5CH2NHCH3 by:-
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 statement(s) is/are incorrect in case of Hofmann bromamide degradation?
Which of the following would not be a good choice for reducing nitrobenzene to aniline?
Amides can be converted into amines by the reaction named ______.
Identify the compo ds A and B in the following reactions:
\[\ce{A ->[Nitrating mixture] B ->[(i) Sn/cone. HCI][(ii) NaOH] Aniline}\]
Write a short note on Ammonolysis.
