CH223 Part 7: Amines (Conceptual) Flashcards
Are amines nucleophilic or electrophilic?
nucleophile, don’t need to be activated with an acid
Nomenclature Rules of Amines
- primary amines are called alkyl amines
- replace alkyl with the name of any alkyl group
- the NH2 group is called amino if other groups have priority
- 2° amines are called dialkylamines or named with an N
- 3° amines are called trialkylamines or named with 2 Ns
- name priority is given to the substituent with more carbons or the cyclic substituent
Are amines more or less basic then alcohols?
more basic
What is the common pKa for ammonia?
around 9
What is the common pKa for alkyl amines?
around 10-11
What is the common pKa for aryl amines?
very low; around 5-1
Why are alkylamines more basic than ammonia?
the EDG is more willing to share electrons
Why are alkylamines more basic than arylamines?
the loss of a proton for arylamines causes it to have no resonance
What is the effect of EDGs on alkylamine basicity?
increases basicity due to inductive stability
What is the effect of EWG on alkylamine basicity?
decreases basicity due to destabilizing resonance
Why does a nucleophilic substitution with alkyl halides and ammonia make a salt?
the product is very nucleophilic so it just keeps reacting
What is the best way to make an amine?
gabriel synthesis with phthalimide (acts as a protecting group)
What is reductive amination used for?
the synthesis of 2° amines
Why does the reductive amination reaction use NaBH3CN instead of NaBH4?
since the iminium ion is so electrophilic, NaBH4 doesn’t have to be crazy reactive
What is a Hofmann Elimination?
the use of quaternary ammonium salts as an intermediate for the synthesis of alkenes
