Amines - Chp 19 Flashcards
NH2 group added to a benzene is called…
Aniline.
Which has lower b.ps? Tertiary or secondary/primary amines? Why?
Tertiary b/c it cannot H-bond.
______ amines are soluble in water.
Small
Do all amines accept H-bonds from water and alcohols?
Yes.
Give the order of basicity of amines from least to greatest in gas phase.
NH3 < RNH2 < R2NH < R3N
(tertiary is the highest/most basic)
Give the order of basicity of amines from least to greatest in solution phase.
NH3 < R3N < RNH2 < R2NH
Amines react as ______
with compounds that
contain _______________.
bases; acidic protons
Amines can react as both Nu and bases. True or false?
True.
Which has less s character? Sp3 or sp2?
sp3
Which is less basic? Amides or amines?
Amides
Electron donating groups makes the amine more ________ than ________.
basic; aniline
List 5 electron donating groups.
-NH2
-OH
-OR
-NHCOR
-R (ex.CH3)
List at electron withdrawing groups.
-CHO
-COR
-COOH
-CN
-NO2
-SO3H
-NR3+
List in order of increasing basicity.
Pyrrole, piperidine, pyridine, aniline
pyrrole, aniline, pyridine, piperidine
How does resonance affect basicity?
It decreases it.
Which has a higher s-character? sp3 or sp2? What does it mean?
sp2; the more tightly the lone pair is held, and the weaker the base.
Electron withdrawing groups makes the amine ______ basic than aniline.
less
Which is more basic between amide and amine? Why?
Amide b/c the electron pair on the nitrogen is delocalized.
Aldehydes or ketones reacting with primary amines forms what?
Imine
C=N-R’
Aldehydes or ketones reacting with secondary amines forms what?
=C-NR’2
Is NH2 a strong activator or deactivator? Ortho, para, or meta?
Activator; ortho and para director.
Aromatic substitution of pyridine goes to which position? Why?
Meta position; 2 or 4-position would have an unfavorable resonance structure in
which the positive charge is localized on the nitrogen
Nucleophilic substitution of pyridine goes to which position? Why?
Ortho and para position (2- or 4-position); b/c it places a negative charge on the N.
Primary or secondary amines react with acid halides to form what?
Amides.
(through nucleophilic acyl substitution)
Hofmann elimination convert amine to _______ using ___ (E1E2) elimination.
alkene; E2
What is the difference b/w E2 elimination reactions using alkyl halides and amines?
Alkyl halides form a more substituted major product while amines form the less substituted major product.
Nitrous acid (HNO2) reacts with 1° alkylamines and arylamines to form…
diazonium salts
Acylation–reduction converts a secondary amine to __________ using _____ reagent.
tertiary amine; LiAlH4
