Nitrogen compounds Flashcards
Synthesis of amines/phenylamines
- Nucleo sub of RX
- Reduction of amides
- Reduction of nitriles
$. Reduction of nitrobenzene to phenylamine (ONLY WAY!)
R&C for nucleo sub of RX
Mono-sub: Excess NH3 in ethanol, heat in sealed tube
R&C for reduction of amides to amines
LiAlH4 in dry ether
R&C for reduction of nitriles to amines
LiAlH4 in dry ether OR H2, Ni, heat
Reactions of amines/ phenylamines
- Condensation of amines to amides
- Acid-base reaction
- Phenylamines: Electo-sub
Distinguishing test for phenylamines
Electro-sub
Observations:
1. Orange Br2 decolourises
2. White ppt of 2.4.6-tribromophenylamine formed
3. White fumes of HBr
R&C for nitrobenzene to phenylamine
- Sn, conc HCl. heat under reflux
- NaOH (aq)
R&C for acid-base rxn for amines
HCl(aq)
* All amines are lewis bases
R&C for condensation of amines to amides
anhydrous acyl chloride, rtp
Why are phenylamines more reactive towards electrosub than phenols?
- N is less EN than O
- LP of electrons on N delocalises into benzene ring to a larger extent than LP of electrons on O
- Benzene in phenylamine more electron rich than in phenol
- Phenylamines more reactive
Synthesis of amides
- Condensation of amines to amides (ONLY ONE WAY)
Reactions of amides
- Hydrolysis
- Reduction
Explain the basicity of nitrogen compounds
- electron-donating –> electron density on N increases –> LP of electrons more available for donation –> Strong base
R&C for hydrolysis of amides and products
Acidic Hydrolysis:
R&C: H2SO4, heat
Basic Hydrolysis:
R&C: NaOH, heat