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In the Hofmann-Bromamide rearrangement i...

In the Hofmann-Bromamide rearrangement intermediate
compounds are :

A

`R - CONHBr`

B

`[ R - overset(overset(O)(||))C - bar(N) - Br ] Na^(+)`

C

`R - N = C = O`

D

All of these

Text Solution

AI Generated Solution

The correct Answer is:
To solve the question regarding the intermediate compounds in the Hofmann-Bromamide rearrangement, we will outline the process step by step. ### Step-by-Step Solution: 1. **Understanding the Reaction**: The Hofmann-Bromamide rearrangement involves the conversion of a primary amide into a primary amine with the loss of one carbon atom. The general structure of the starting material is R-C(=O)-NH2. 2. **Initial Reaction with Bromine**: The primary amide (R-C(=O)-NH2) reacts with bromine (Br2) in the presence of a base such as sodium hydroxide (NaOH). This leads to the formation of an N-bromoamide intermediate: \[ R-C(=O)-NH2 + Br2 + NaOH \rightarrow R-C(=O)-NBr + HBr + H2O \] Here, the first intermediate is R-C(=O)-NBr. 3. **Formation of Isocyanate**: The N-bromoamide can further react with hydroxide ions (OH-) to form an isocyanate intermediate: \[ R-C(=O)-NBr + OH- \rightarrow R-N=C=O + Br- + H2O \] This is the second intermediate, which is the alkyl isocyanate (R-N=C=O). 4. **Hydrolysis of Isocyanate**: The isocyanate (R-N=C=O) can undergo hydrolysis in the presence of water to yield the primary amine: \[ R-N=C=O + H2O \rightarrow R-NH2 + CO2 \] This results in the formation of the final product, which is the primary amine (R-NH2). 5. **Summary of Intermediates**: The intermediates formed during the Hofmann-Bromamide rearrangement are: - N-bromoamide (R-C(=O)-NBr) - Alkyl isocyanate (R-N=C=O) ### Final Answer: The intermediate compounds in the Hofmann-Bromamide rearrangement are: 1. N-bromoamide (R-C(=O)-NBr) 2. Alkyl isocyanate (R-N=C=O)
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