हिंदी
Karnataka Board PUCPUC Science 2nd PUC Class 12

Preparation of Amines

Advertisements

Topics

Estimated time: 10 minutes
CBSE: Class 12
Maharashtra State Board: Class 12

Key Points: Preparation of Amines

Reduction of Alkyl Nitriles (Nitrile Reduction):

\[ \mathrm{R} - \mathrm{C} \equiv \mathrm{N} \xrightarrow[\mathrm{LiAlH}_4 \text{ or } \mathrm{Na} / \mathrm{C}_2\mathrm{H}_5\mathrm{OH}]{\text{Raney Ni} / \mathrm{H}_2} \mathrm{R} - \mathrm{CH}_2\mathrm{NH}_2 \]

Reduction of Amides:

\[ \mathrm{R} - \mathrm{CONH}_2 \xrightarrow{\mathrm{LiAlH}_4 / \text{ether}} \mathrm{R} - \mathrm{CH}_2\mathrm{NH}_2 \]

Reduction of Oximes:

\[ \mathrm{R} - \mathrm{CH} = \mathrm{NOH} + 4[\mathrm{H}] \xrightarrow[\mathrm{LiAlH}_4]{\mathrm{Na} / \mathrm{C}_2\mathrm{H}_5\mathrm{OH}} \mathrm{R} - \mathrm{CH}_2\mathrm{NH}_2 + \mathrm{H}_2\mathrm{O} \]

Reductive Amination (from Aldehydes/Ketones):

\[ \mathrm{R} - \mathrm{CH} = \mathrm{O} \xrightarrow{\mathrm{NH}_2\mathrm{OH}} \mathrm{R} - \mathrm{CH} = \mathrm{N} - \mathrm{OH} \xrightarrow{\mathrm{LiAlH}_4} \mathrm{R} - \mathrm{CH}_2 - \mathrm{NH}_2 \]

Gabriel Phthalimide Reaction (for 1° amines only):

Hoffmann Bromamide Degradation (gives 1° amine with one less carbon):

\[ \underset{\text{Amide}}{\mathrm{RCONH}_2} + \mathrm{Br}_2 + 4\mathrm{KOH} \longrightarrow \underset{1^\circ \text{ amine}}{\mathrm{RNH}_2} + 2\mathrm{KBr} + 2\mathrm{H}_2\mathrm{O} + \mathrm{K}_2\mathrm{CO}_3 \]

Mechanism:

 
Schmidt Reaction:
Monocarboxylic acid react with hydrazoic acid give primary amine.
\[ \underset{\text{Acid}}{\mathrm{RCOOH}} + \underset{\text{Hydrazoic acid}}{\mathrm{N}_3\mathrm{H}} \xrightarrow{\mathrm{H}_2\mathrm{SO}_4} \underset{1^\circ\text{amine}}{\mathrm{RNH}_2} + \mathrm{CO}_2 + \mathrm{N}_2 \]
In this reaction
 
Mendius Reaction:
Alkyl cyanide on reduction with Na+ C2H5OH gives a primary amine. This reaction is known as Mendius reaction.
\[ \underset{\text{Alkylcyanide}}{\mathrm{RCN}} + 4[\mathrm{H}] \xrightarrow[\text{or } \mathrm{Na}/\mathrm{C}_2\mathrm{H}_5\mathrm{OH} \text{ or } \mathrm{LiAlH}_4]{\mathrm{H}_2/\mathrm{Ni}} \underset{1^\circ\text{amine}}{\mathrm{RCH}_2\mathrm{NH}_2} \]

Shaalaa.com | Preparation :- Reduction of nitro compounds

Shaalaa.com


Next video


Shaalaa.com


Preparation :- Reduction of nitro compounds [00:06:42]
S
Advertisements
Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×