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Organic Chemistry , 6 th Edition L. G. Wade, Jr. Chapter 21 Carboxylic Acid Derivatives (continued). Jo Blackburn Richland College, Dallas, TX Dallas County Community College District ã 2006, Prentice Hall. =>. Hydrolysis of Acid Chlorides and Anhydrides.

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chapter 21 carboxylic acid derivatives continued

Organic Chemistry, 6th EditionL. G. Wade, Jr.

Chapter 21Carboxylic Acid Derivatives(continued)

Jo Blackburn

Richland College, Dallas, TX

Dallas County Community College District

ã 2006,Prentice Hall

hydrolysis of acid chlorides and anhydrides

=>

Hydrolysis of Acid Chlorides and Anhydrides
  • Hydrolysis occurs quickly, even in moist air with no acid or base catalyst.
  • Reagents must be protected from moisture.

Chapter 21

acid hydrolysis of esters

=>

Acid Hydrolysis of Esters
  • Reverse of Fischer esterification.
  • Reaches equilibrium.
  • Use a large excess of water.

Chapter 21

saponification
Saponification
  • Base-catalyzed hydrolysis of ester.
  • “Saponification” means “soap-making.”
  • Soaps are made by heating NaOH with a fat (triester of glycerol) to produce the sodium salt of a fatty acid - a soap.
  • One example of a soap is sodium stearate, Na+ -OOC(CH2)16CH3. =>

Chapter 21

hydrolysis of amides

=>

Hydrolysis of Amides

Prolonged heating in 6 M HCl or 40% aqueous NaOH is required.

Chapter 21

hydrolysis of nitriles

=>

Hydrolysis of Nitriles
  • Under mild conditions, nitriles hydrolyze to an amide.
  • Heating with aqueous acid or base will hydrolyze a nitrile to an acid.

Chapter 21

reduction to alcohols

=>

Reduction to Alcohols

Lithium aluminum hydride reduces acids, acid chlorides, and esters to primary alcohols.

Chapter 21

reduction to aldehydes

=>

Reduction to Aldehydes

Acid chlorides will react with a weaker reducing agent to yield an aldehyde.

Chapter 21

reduction to amines

=>

Reduction to Amines
  • Lithium aluminum hydride reduces amides and nitriles to amines.
  • Nitriles and 1 amides reduce to 1 amines.
  • A 2 amide reduces to a 2 amine.
  • A 3 amide reduces to a 3 amine.

Chapter 21

organometallic reagents

=>

Organometallic Reagents

Grignard reagents and organolithium reagents add twice to acid chlorides and esters to give alcohols after protonation.

Chapter 21

grignard reagents and nitriles

=>

Grignard Reagentsand Nitriles

A Grignard reagent or organolithium reagent attacks the cyano group to yield an imine which is hydrolyzed to a ketone.

Chapter 21

acid chloride synthesis

=>

Acid Chloride Synthesis
  • Use thionyl chloride, SOCl2, or oxalyl chloride, (COCl)2.
  • Other products are gases.

Chapter 21

acid chloride reactions 2

acylbenzene

=>

Acid Chloride Reactions (2)

3° alcohol

ketone

1° alcohol

aldehyde

Chapter 21

AlCl3

industrial synthesis of acetic anhydride

=>

Industrial Synthesis of Acetic Anhydride
  • Four billion pounds/year produced.
  • Use high heat (750°C) and triethyl phosphate catalyst to produce ketene.

Chapter 21

lab synthesis of anhydrides

=>

Lab Synthesisof Anhydrides
  • React acid chloride with carboxylic acid or carboxylate ion.
  • Heat dicarboxylic acids to form cyclic anhydrides.

Chapter 21

anhydride reactions

acylbenzene

=>

Anhydride Reactions

acid

ester

amide

AlCl3

Chapter 21

anhydride vs acid chloride

=>

Anhydride vs. Acid Chloride
  • Acetic anhydride is cheaper, gives a better yield than acetyl chloride.
  • Use acetic formic anhydride to produce formate esters and formamides.
  • Use cyclic anhydrides to produce a difunctional molecule.

Chapter 21

synthesis of esters

acid

acid chloride

acid anhydride

=>

methyl ester

Synthesis of Esters

Chapter 21

reactions of esters

3° alcohol

=>

Reactions of Esters

acid

ester

amide

1° alcohol

Chapter 21

lactones

=>

Lactones
  • Formation favored for five- and six-membered rings.
  • For larger rings, remove water to shift equilibrium toward products

Chapter 21

polyesters
Dacron® thread

Mylar® tape

Glyptal resin

PET bottles

=>

Polyesters

Chapter 21

synthesis of amides

acid

acid chloride

acid anhydride

ester

=>

nitrile

Synthesis of Amides

Chapter 21

reactions of amides

nitrile

=>

Reactions of Amides

acid and amine

amine

1° amine

Chapter 21

lactam formation
Lactam Formation
  • Five- and six-membered rings can be formed by heating - and -amino acids.
  • Smaller or larger rings do not form readily. =>

Chapter 21

lactams

Amide  ester !!

=>

-Lactams
  • Highly reactive, 4-membered ring.
  • Found in antibiotics isolated from fungi.

Chapter 21

polyamides
Polyamides

Nylon 6.6

=>

Chapter 21

synthesis of nitriles

1° amide

alkyl halide

diazonium salt

aldehyde or ketone

cyanohydrin

=>

Synthesis of Nitriles

Chapter 21

reactions of nitriles

amide

acid

ketone

=>

Reactions of Nitriles

1° amine

Chapter 21

thioesters

=>

Thioesters

More reactive than esters because:

  • -S-R is a better leaving group than -O-R
  • Resonance overlap is not as effective.

Chapter 21

carbonic acid esters

phosgene

=>

Carbonic Acid Esters
  • CO2 in water contains some H2CO3.
  • Diesters are stable.
  • Synthesized from phosgene.

Chapter 21

urea and urethanes

=>

Urea and Urethanes
  • Urea is the diamide of carbonic acid.
  • Urethanes are esters of a monoamide of carbonic acid.

Chapter 21

polycarbonates

=>

Polycarbonates

Long-chain esters of carbonic acid

Chapter 21

polyurethanes

=>

Polyurethanes

A diol reacts with a diisocyanate.

Chapter 21