Amines Flashcards
1
Q
Amines
A
- Nitrogen has a lone pair
and sp3 hybridization
2
Q
Lewis Base
A
A nucleophile that
uses lone pair to form a bond
with an electrophile
3
Q
Brønsted-Lowry Base
A
Reacting as a nucleophile by
accepting a H acid
4
Q
Basicity of Amines
A
- Need for lone pair want to break
away from the Nitrogen nucleus and form a
bond with H
5
Q
Basicity
A
- pKa of ammonia ions larger stronger base
- Alkyl amines are typically stronger bases than
heterocyclic or aryl amines
6
Q
Factors Affecting Basicity of Amines
A
- In heterocycles, N is sp2
hybridised - Increasing s-character brings electrons
closer to the nucleus - A proton compared to sp3 hybridsed
7
Q
Resonance stabilisation
A
Lone pair shared with the ring
in aryl amines
8
Q
Inductive Stabilisation
A
Alkyl groups donate electron to the more electronegative N increasing the electron
density of N and making it more basic
9
Q
Amines with Ketones and Aldehydes
A
Hydroxyl amines to oxime (OH attached to nitrogen)
10
Q
Resonance Stabilisation
A
- There will be lone pair stabilisation by
the N lone pair - Attack will be ortho or para to the
NH2 group
11
Q
Hofmann Elimination
A
- Methylation of amine heat and base
- Poor ammonia leaving group and good leaving group is with halide
- Least Substituted Alkene is the product
12
Q
Resonance stablisation
A
- Lone pair stablisation via the N lone pair
- Attacks ortho para to the NH2 group
13
Q
Primary amine reaction with primary halide
A
- Formation of the salt of secondary amine +NH2
14
Q
Amine to amide
A
- NH2 attacks acid halide forming the salt
- Pyridine is added causing the neutralisation of HCl
- Amide doesn’t undergo futher actylation
15
Q
Formation of sulphonamides
A
- Primary or secondary amine attacaks sulfonyl chloride to yeild sulphonamide
16
Q
Amine to nitro
A
- Primary amine to hydroxylamine by adding H2O2
- Hydroxylamine to nitroso N=O
17
Q
Nucleophilic aromatic substitution
A
- Cl is a good leaving group Addition of amine causes the replacing of the NH2
18
Q
Thiols
A
- More acidic compared to alcohols
- Formed from SN2 reaction of sodium hydrosulfide
