Chapter 21: Carboxylic Acids and Their Derivatives

Question 1

H3O+, Heat with cyanide group

Answer 1

Hydrolysis of Nitriles

-forms carboxylic acid

Question 2

BH3 THF with carboxylic acid

Answer 2

Reduction of Carboxylic Acids with Borane

-selectively reduces carboxylic acids to alcohols

Question 3

1)LAH, 2)H3O+ with carbonyl

Answer 3

Reduction of Carboxylic Acids with LAH

• the alcohol group is first deprotenated
• this is because the LAH is not a good nuc but instead a good base
• the carbonyl attacks the Al, while the hydride from LAH attacks the carbonyl carbon
• the anion oxiygen then pushes its electron density down and expels the O-AlH2
• another hydride atttacks to form an alkoxide
• H3O+ is added at this point, to protenate the alkoxide

Question 4

SOCl2 with carboxylic acid

Answer 4

Preparation of Acid Chlorides

• carbonyl forms excellent LG with SOCl
• Cl- that was expelled attacks carbonyl and displaces SO2Cl, forms SO2, Cl-

Question 5

H2O with Acid Chloride

Answer 5

Hydrolysis of Acid Chlorides

• H2O nuc attacks carbonyl
• Cl leaves as LG
• H2O is deprotenated

Question 6

ROH, Pyridine with Acid Chloride

Answer 6

Alcoholysis of Acid Chlorides

• ROH nuc attacks carbonyl
• Cl leaves as LG
• ROH is deprotenated
  
  • pyrdine is used to neutralize HCl

Question 7

2 NH3 with Acid Chloride

Answer 7

Aminolysis of Acid Chlorides

• NH3 nuc attacks carbonyl
• Cl leaves as LG
• NH3 is deprotenated
  
  • pyrdine is used to neutralize HCl
  • canwork for primary and secondary amines

Question 8

1)Excess LAH 2) H2O with Acid Chloride

Answer 8

Reduction of Acid Chlorides

• LAH delivers hydride
• carbonyl reforms, expells Cl
• LAH delivers hydride
• H2O protenated alkoxide ioN

Question 9

1)LiAl(OR)3H 2)H2O with Acid Chloride

Answer 9

Reduction of Acid Chloride

-reaction with aldehyde occurs more slowly, so reaction simply produces carbonyl

Question 10

1) Excess RMgBr 2)H2O with Acid Chloride

Answer 10

Acid Chloride and Grignard Reagent

• R- nuc attacks carbonyl
• carbonyl reforms, expels Cl
• R- attacks again
• H2O protenates alkoxide ion

Question 11

R2CuLi with Acid Chloride

Answer 11

Reaction between Acid Chlorides and Organometallic Reagents
0Cu forms less polarized bonds
-can produce ketones

Question 12

800 deg C with carboxylic acid

Answer 12

Preparing Acid Anhydride
Can convertcarboxylic acid to acetic anhydride
-only useful for acetic acid
-forms H2O as side product

Question 13

Carboxylate ion with acid chloride

Answer 13

Preparing Acid Anhydride

-nuc attack and loss of Cl

Question 14

1) NaOH 2) R-I with carboxylic acid

Answer 14

Preparation of Esters via SN2

• carboxylate ion acts as nuc that attacks the R gorup
• tert alkyl halides don’t work

Question 15

R-OH, [H+] with carboxylic acid

Answer 15

Preparation of Esters Via Fisher Esterification

• carbonyl on carboxylic acid is protenated
• acid attacks carbonyl C
• acid deprotenated
• hydroxyl protenated
• carbonyl reforms, pushes off H2O
• carbonyl deprotenated

Question 16

ROH, Pyridine with Acid Chloride

Answer 16

Preparation of Esters Via Acid Chlorides

• ROH nuc attacks carbonyl
• Cl leaves as LG
• ROH is deprotenated
  
  • pyrdine is used to neutralize HCl

Question 17

1) NaOH 2) H3O+ with ester

Answer 17

Saponification

• BASIC conditions
• OH attacks carbonyl
• OR leaves
• OR is protenated by OH
• carboxylate ion must thenbe protenated in 2nd step

Question 18

H3O+ with ester

Answer 18

Acid-Catalyzed Hydrolysis of Esters

• carbonyl is protenated
• H2O attacks carbonyl
• H2O deprotenated
• O-R protenated
• carbonyl reforms, ester-H leaves
• carbonyl deprotenated

Question 19

NH3

Answer 19

Aminolysis of Esters

Slow reaction, not as practical as acid chloride

Question 20

1)Excess LAH 2) H2O with ester

Answer 20

Reduction of Esters

• LAH delivers hydride
• carbonyl reforms, expells R-O
• LAH delivers hydride
• H2O protenated alkoxide ion

Question 21

DIBAH, low temp. with ester

Answer 21

Reduction of Esters

-stops reduction at aldehyde

Question 22

1) Excess RMgBR 2)H2O with ester

Answer 22

Grignard Reaction with Esters

• Two R groups and an OH as product
• R- nuc attacks carbonyl
• carbonyl reforms, expels RO
• R- attacks again
• H2O protenates alkoxide ion

Question 23

H3O+ heat with amide

Answer 23

Acid Catalyzed Hydrolysis of Amides

• carbonyl is protenated
• H2O attacks carbonyl
• H2O deprotenated
• NH2 protenated
• carbonyl reforms, NH3 leaves
• carbonyl deprotenated

Question 24

1)NaOH, heat 2) H3O+ with amide

Answer 24

Base-Catalyzed Hydrolysis of Amides

• BASIC conditions
• OH attacks carbonyl
• OR leaves
• NH2 is protenated by OH
• carboxylate ion must thenbe protenated in 2nd step
• deprotenation of carboxylic acid makes reaction irreversible

Question 25

NaCN with alkyl halide

Answer 25

Preparation and Reactions of Nitriles Via SN2 Reactions Cyanide replaces halide

Question 26

SOCl2 with nitrile

Answer 26

Preparation and Reactions of Nitriles Via Amides -carbonyl double bond attacks S, N lone pair forms double bond -S-O forms carbonyl expels Cl -Base deprotenated NH2 -Base deprotenates NH, forms triple bond (N-C) and O-S forms double bond, Cl expelled

Question 27

H3O+, Heat with nitrile | Acid-catalyzed

Answer 27

``` Hydrolysis of Nitriles N is protenated with H3O+ -H2O attacks C -H2O is deprotenated -NH is protenated [resonance: OH forms carbonyl, NH gets e- from double bond] -carbonyl is deprotenated -forms amide ```

Question 28

1)NaOH, H2O 2)H3O+ wth nitrile

Answer 28

``` Base-catalyzed Hydrolysis of Nitriles --OH attacks C -N is protenated -Oh deprotenated [resonance: O- forms carbonyl] -N- is protenated ```

Question 29

1) RMgBr 2)H3O+ with Nitrile

Answer 29

Reactions With Grignard Reagents and Nitriles - grignard attacks carbonyl, forms N- - treated with acid to form imine - hydrolyzed to ketone under acidic conditions

Question 30

1) Excess LAH 2) H2O

Answer 30

Reductions of Nitriles | -Forms amine at end of carbon