ACYLATION Flashcards
(20 cards)
What is acylation? (1)
the process by which the acyl group is introduced into another molecule
what group of molecules have the acyl group as part of their structure? (1)
acid derivatives
what are the most important acid derivatives? (1)
acid chlorides and acid anhydrides
what are acid derivatie=ves structure of? (1)
acid derivatives are derived from carboxylic acids
what is the general formula for an acid derivative? (1)
R-C=O -Z
how is a carbonyl group polarised in an acid derivative? (1)
it is attacked by nucleophiles at the C+ ans in the process, the nucleophile replaces Z and the nucleophile therefore acquires an acyl group, so the nucleophile has been acylated.
what does how readily a reaction occurs depend on? (3)
-the magnitude of the delta + charge on the carbonyl carbon, which in turn depends on the electron-releasing or attracting power
-how easily Z is lost, (z is called the leaving group)
-how good the nucleophile is
whic factors that effect how reasily a reaction occurs are linked? (1)
groups with are strongly attract electrons tend to form stable negative ions, Z-, and are good leaving groups
what is special about the Z groups of acid chlorides and anhydrides? (1)
Z groups withdraw electrons from the carbonyl carbon, which makes the carbon more positive and makes these compounds reactive towards nucleophiles. so acyl chlorides and anhydrides are good acylating agents.
what are nucleophiles? (1)
must have a lone pair of electrons which they use to attack an electron-deficient carbon, C+.
what nucleophiles will acyl chlorides and hydrides react with in order of reactivity? (4)
- primary amine
- ammonia
- alcohol
- water
what is the reaction called between an acyl chloride or anhydride and a nucleophile? (1)
addition-elimination reactions
what is the product of an addition-elimination reaction involving the nucleophile ammonia? (1)
product is an amide
what is the product of an addition-elimination reaction involving the nucleophile primary amine? (1)
product is an N-substituted amide
what is the product of an addition-elimination reaction involving the nucleophile alccohol? (1)
an ester
what is the product of an addition-elimination reaction involving the nucleophile water? (1)
a carboxylic acid
ALL OTHER MECHANISMS ARE ON PHYSICAL CARDS
What are the uses of acylation reactions? (1)
ethanoic anhydride is manufactured on aa large scale as it possesses advantages over ethanoyl chloride.
what are the advantages of using ethanoic anhydride over ethanoyl chloride? (4)
-its cheaper
-its less corrosive
-it does not react with water as readily
-it is safer
-it produces aspirin
