Carboxylic acid derivatives_1 Flashcards

Terms Definitions
Benzoic Acid
Formic Acid
Common name for 1,5-pentanediamine
As resonance donation increases, restricted rotation ________.
Naming: Nitrile
1) Alkanenitrile
2) Example: 4-oxopentanenitrile
Anhydride + Alcohol -->
Mechanism: NAS
As resonance donation increases, C=O IR peak ________.
Carboxylic Acid + SOCl2 -->
Acyl Halide
Mixed Claisen w/ ketones -->
Mechanism: Use alkoxide anion corresponding to alkyl group on ester O -> alpha-C of ketone deprotonated -> alpha-C of ketone attacks C of 2nd carbonyl -> lose LG
Beta-dicarbonyl compound
Naming: Anhydride
1) Alkanoic Anhydride
2) Example: propanoic anhydride
Acyl Halide + Carboxylic Acid -->
Mechanism: NAS
reduction-esters by DIBAlH
-Diisobutylaluminum hydride (DIBAlH) at -78 selectively reduces ester to aldehyde
*at -78 TCAI doesn't collapse and it's not til hydrolysis in aqueous A that C=O group of aldehyde is liberated
Nitrile + H2, Pd -->
Mechanism: Nu Addition
(Ketone or Aldehyde) + Amine -->
Imine (C=N)
Nitrile + Water, H+/OH- -->
Mechanism: Nu Addition
Carboxylic Acid
Naming: Carboxylate Anion
1) Alkanoate Anion
2) Example: propanoate anion
Naming: Nitrile as substituent
1) Cyano
2) Example: 4-cyanopentanoic acid
Naming: Carboxylic Acid
1) Alkanoic Acid
2) Example: propanoic acid
Naming: Amide
1) Alkanamide
2) Substituents on N
a) N-alkyl
b) N,N-dialkyl
c) N-ethyl-N-methyl
3) Example: N-methylpropanamide
Nitrile + 1) LAH 2) Water, H+ -->
Mechanism: Nu Addition
Amide + 1) LAH 2) Water, H+ -->
Mechanism: Add H- -> Elim O- due to e- donation of N (form db) -> Add H- (e- moves back onto N)
acidity of NH bonds
-amides=comparable to alcohols in acidity
*H2O insoluble amides don't react w/ NaOH/other alkali metal hydroxides to form H2O soluble salts
-sulfonamides and imides=more acidic than amides
*imides=more acidic bcuz:
1. e- w/drawing inductive effect of 2 adjacent C=O groups weakens NH bond
2. imid anion is stabilized by resonance delocalization of neg. charge
rxn w/ H2O-esters contd
-saponification: hydrolysis of an ester in aqueous B
*each mole of ester hydrolyzed requires 1 mole B
*involves formation of TCAI followed by its collapse and proton transfer
R-X + Mg -->
(Changes partial - R group into partial + R group)
RMgX (Grignard)
Boiling point trends
1) Amines higher that similar sized alkanes
2) Amines lower than similar sized alcohols
3) Tertiary amines lower than primary/secondary of similar size
a) Due to lack of H-bonding
Naming: Order of precedence
Carboxylic acids & derivatives > nitriles > aldehydes > ketones > alcohols > amines > alkenes, alkynes
rxn w/ alcohols
-sulfonic acid esters prepared by rxn of alkane/arenesulfonyl chloride w/ alcohol or phenol
*key pt is that OH- (poor LG) transformed into sulfonic ester (good LG) w/ retention of configuration at chiral center
rxn w/ H2O-nitriles
-cyano group is hydrolyzed in aqueous A to a carboxyl group and ammonium ion
*protonation of cyano N gives cation that reacts w/ H2O to give imidic acid
*keto-enol tautomerism gives the amide
-hydrolysis in aqueous B gives carboxylic anion and ammonia; acidification then converts anion to carb. acid
-hydrolysis of nitriles=valuable route to carb acids
reduction-nitriles by LiAlH4
-cyano group of nitrile reduced by LiAlH4 to 1' amine
Rxn w/ H2O-acid chlorides
-low MW acid chlorides react rapidly w/ H2O
*higher MW acid chlorides=less soluble in H2O and react less readily
reduction-esters by LiAlH4
-most reductions of C=O compounds now use hydride reducing agents
*esters reduced by LiAlH4 to 2 alcohols
*alcohol derived from C=O group is primary
-3 steps plus workup:
1 and 2. reduce ester to an aldehyde
3. reduction of aldehyde followed by workup gives 1' alcohol derived from C=O group
Define: Enolate
An anion derived bg the loss of a proton from the alpha-carbon of a carbonyl group. They are stabilized by resonance.
Nitrile + 1) RLi or RMgX 2) Water, H+ -->
Mechanism: Nu Addition
acid chlorides w/ salts
-acid chlorides react w/ salts of carb. acids to give anhydrides
*most commonly used are Na or K salts
rxn w/ H2O-amides contd
2 steps in aqueous A:
1. protonation of C=O O gives resonance-stabilized cation intermediate
2. addition of H2O (Nu) to C=O C (electrophile) followed by proton transfer gives TCAI
rxn w/ ammonia, etc.
-acid halides react w/ ammonia, 1' amines, and 2' amines to form amides
*2 moles amine required per mole of acid chloride
-acid anhydrides react w/ ammonia, and 1' and 2' amines to form amides
*2 moles ammonia/amine required
-esters react w/ ammonia and w/ 1' and 2' amines to form amides
*esters=less reactive than acid halides and anhydrides
-amides don't react w/ ammonia or w/ 1' or 2' amines
Trends in amine basicity
1) Amines > anilines > amides > nitriles
2) e- donating groups increase basicity
3) e- withdrawing groups decrease basicity
4) hybridization increases basicity
a) sp3 > sp2 > sp
5) amines more basic than alcohols (o more EN), amides (resonance)
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