Acid Derivatives (anhydrides, amides, esters)

Question 1

factors in derivative stability

Answer 1

o has partial neg (good nucleophone, wants to bond to electrophiles)
c has partial pos (good electrophile, wants electrons

1. leaving group stability
2. charge (how much inc/dec charge on carbon, more pos charge is more reactive)

Question 2

what does group attached to carbonyl affect?

Answer 2

reactivity

higher energy is more reactive
lower energy is less reactive

Question 3

how to stabilize charge

Answer 3

they have opposite effects
_______________________________
induction - pushing or pulling electron density across polar bonds

At carbonyls electrons are pulled away from carbonyl making it positive and reactive

resonance - partial double bond through carbon makes carbon less reactive

Question 4

stability of acid derivatives ranked

Question 5

stability of acid derivatives

Answer 5

amides are most stable with NH2 group

induction
N is less EN than O and less able to draw density from carbon carbon

amide nitrogen bonded to 2 Hs which are less EN than N so they donate electron density

it doesnt pull E density from carbon

**leaving group
**forms NH2-, bc N less EN than O, it cant stabilize a negative charge and it is not a good leaving group

**resonance
**nitrogen can donate a pair to oxygen which makes N more positve
large effect and makes carbonyl carbon less positive

Question 6

why does it matter than amides are very stable and not reactive?

Answer 6

peptide bonds in proteins are amide bonds so life depends on the stability of amides

Question 7

stability of esters

Answer 7

O has higher EN than C and it can pull more electron density from C and increases its positivy

only one R group (H) donating electron yadensity compared to 2 groups in amides

Question 8

why are amides generally less reactive than carboxylic acids?

Answer 8

nitrogen allows for resonance which increases stability and decreases the partial positive charge on the carbonyl carbon and makes it less reactive

Nitrogen donates a lone pair through resonance

greater stability means less reactive

Question 9

what kind of reaction is this?

Answer 9

an ester with an alcohol and a base or acid
transesterification which produces another ester and alcohol

Question 10

which one of the acyl halides is the most reactive to nucleophillic substitution?

Answer 10

reactivity depends on stability of leaving group (good leaving group increases reactivity)

most stable leaving group is idodine due to its increased atomic radius which means an ion is able to disperse a neg charge over greater area which increases stability

atomic radius increases down peroid, so idodine is largest

Question 11

how is peptide bond breakage an example of amide hydrolysis

Answer 11

amide hydrolysis is a breakdown of an amide into a carboxylic acid and an amine group through the addition of water. The breaking of peptide bonds between amino acids breaks up an amide through the addition of water and forms a carboxylic acid on one amino acid and an amine group on another