Ch. 9: Carboxylic Acid Derivatives

Question 1

Amides

Answer 1

Condensation products of carboxylic acids and ammonia or amines.

Question 2

Amide nomenclature

Answer 2

Given suffix -amide The alkyl groups on a substituted amide are written at the beginning of the name w the prefix N-

Question 3

Cyclic amides

Answer 3

Called lactams. Named by the greek letter of the carbon forming the bond w the nitrogen (beta lactam, gamma lactam etc)

Question 4

Esters

Answer 4

Condensation products of carboxylic acids w alcohols (Fischer esterification)

Question 5

Ester nomenclature

Answer 5

given the suffix -oate. The esterifying group is written as a substituent w/o a number

Question 6

Cyclic esters

Answer 6

Called lactone. Named by the number of carbons in the ring and the Greek letter of the carbon forming the bond with the oxygen (alpha acetolactone, beta propiolactone, and so on)

Question 7

Triacylglycerols

Answer 7

A form of fat storage, include 3 ester bonds between glycerol and fatty acids

Question 8

Anhydrides

Answer 8

Condensation dimers of carboxylic acids. Some cyclic anhydrides can be synthesized by heating dioic acids. Five-or six membered rings are generally stable

Question 9

Anhydride nomenclature

Answer 9

Symmetric anhydrides are named for the parent carboxylic acid, followed by anhydride. Asymetric anhydrides are named by listing the parent carboxylic acids alphabetically, followed by anhydride.

Question 10

Relative reactivity in nucleophilic substitution reactions

Answer 10

Anhydrides are more reactive than esters which are more reactive than amides

Question 11

Steric hindrance

Answer 11

Describes when a rxn cannot proceed (or significantly slows) bc of substituents crowding the reactive site.

Question 12

Protecting groups

Answer 12

Such as acetals, can be used to increase steric hindrance or otherwise decrease the reactivity of a particular portion of a molecule

Question 13

Induction

Answer 13

Refers to uneven distribution of charge across a σ bond bc of differences in electronegativity. The more electronegative groups in a carbonyl-containing compound, the greater its reactivity

Question 14

Conjugation

Answer 14

Refers to the presence of alternating single and multiple bonds, which creates delocalized pi electron clouds above and below the plane of the molecule

Question 15

Resonance

Answer 15

Electrons experience resonance through the unhybridized p-orbitals, increasing stability. Conjugated carbonyl containing compounds are more reactive bc they can stabilize their transition states

Question 16

Strain relation to reactivity

Answer 16

Increased strain in a molecule can make it more reactive. Beta lactams are prone to hydrolysis bc they have significant ring strain

Question 17

Ring strain

Answer 17

Due to torsional strain from compressing bond angles below 109.5*

Question 18

Determination of rate of nucleophilic substitution rxns

Answer 18

All carboxylic acid derivatives can undergo nucleophilic substitution rxns. The rates at which they do so are determined by their relative reactivities

Question 19

Cleavage in anhydrides

Answer 19

Anhydrides can be cleaved by the addition of a nucleophile. Addition of ammonia or an amine results in an amide and a carboxylic acid. Addition of an alcohol results in an ester and a carboxylic acid. Addition of water results in 2 carboxylic acids

Question 20

Transesterification

Answer 20

Exchange of one esterifying group for another on an ester. The attacking nucleophile is water or the hydroxide anion

Question 21

Amides

Answer 21

Can be hydrolyzed to carboxylic acids under strongly acidic or basic conditions. The attacking nucleophile is water or the hydroxide anion