The most important acid derivatives are esters, amides and nitriles, although acid halides and anhydrides are also derivatives (really activated forms of a
all derivatives of carboxylic acids: amides is due to the strong dipolar forces that The reactivity of acid derivatives can be correlated
derivative (amides and esters) are more readily prepared from more reactive acyl derivatives (acid chlorides and anhydrides) carboxylic acid amide
Amides: Primary amides (RCONH2) are named as the carboxylic acid except the -ic acid ending is replaced with -amide or the -carboxylic acid ending is replaced
Since the acid chloride is more reactive than the anhydride, ester or amide, the acid chloride can be converted directly to any of these acyl derivatives
Esters are derivative of carboxylic acids in which the –OH group on the carboxyl has been replaced with an –OR group Esterification (Preparation of Esters)
An amide is a composite of a carboxylic acid and either ammonia or an amine R may be H, alkyl or aryl Amides are derivatives of carboxylic acids, derived by
amide acid chloride acid anhydride
Esters and amides, however, are universally present Amide Ester Anhydride Acid halide Increasing reactivity toward nucleophilic acyl substitution R O
all derivatives of carboxylic acids: R acid ester anhydride acyl halides amides compounds with groups that can be Interconversion of Acid Derivatives (21-5)
Derivatives of carboxylic acids Vladimíra can be oxidized to oxo derivatives (= dehydrogenation) products of esterification (acid + alcohol → ester + water)
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Derivatives of carboxylic acids
Vladimíra Kvasnicová
Derivatives of carboxylic acids
1. substitutional derivatives→substitution in the chain of an acid →no change in the carboxyl group
2. functional derivatives
→functional carboxyl group is changed
Substitutional derivatives
•substitution in the chain of an acid
1.1. HALOGEN DERIVATIVES
R(X)- COOHX = Cl, Br, I, F
•prefix : chloro-, bromo-, iodo-, fluoro-
1.2. HYDROXY DERIVATIVES
R(OH)- COOH
•prefix : hydroxy- • can be oxidized to oxo derivatives (= dehydrogenation) •trivial names! •lactic acid(= 2-hydroxypropanoic acid or a-hydroxypropionic acid) • bbbb-hydroxybutyric acid (= 3-hydroxybutanoic acid) •malic acid(= 2-hydroxybutanedioic acid or a-hydroxysuccinic acid) •citric acid(= 2-hydoxypropane-1,2,3-tricarboxylic acid) •salicylic acid(= 2-hydroxybenzoic acid)
Important hydroxy derivatives
1.3. OXO DERIVATIVES
R- (C ═O)- COOH •prefix: oxo- / keto- • can be reduced to hydroxy derivatives•trivial names!Important oxo derivatives: pyruvic acid(= 2-oxopropanoic acid) acetoacetic acid(= 3-oxobutanoic acid) oxaloacetic acid(= 2-oxobutanedioic acid) aaaa-ketoglutaric acid(= 2-oxopentanedioic acid)
1.4. AMINO DERIVATIVES
R(NH
2)- COOH
•prefix : amino- •a-L-amino acids are found in proteins •trivial names!examples:•glycine(= 2-aminoethanoic acid) •alanine (= 2-aminopropanoic acid) •phenylalanine(= 2-amino-3-phenylpropanoic a.)
Functional derivatives
•functional carboxyl group is changed
2.1. SALTS
R- COO
-M + (M += metal cation) = products of neutralization (acid + base →salt + water) •suffix : -ate or -oate -ic acid →-ate / -oic acid →-oate • R- COO-= carboxylate (anion of c.a.) •full name:cation carboxylate (sodium acetate)
2.2. ESTERS
R1- O-
CO- R 2 = products of esterification (acid + alcohol →ester + water) • the opposite reaction = ester hydrolysis •suffix : -ate •R1- O- = rest of alcohol • R1 = alkyl (from the alcohol name: "alkyl" alkohol) •full name : alkyl carboxylate(methyl acetate = methyl ethanoate)
• ethyl formate = ethyl methanoate• methyl benzoate• methyl salicylate ¹acetylsalicylic acid
• phenyl acetate = phenyl ethanoate • CH 3-CH 2-CH
2-CO-O-CH
3(apple)
• CH 3-CH 2-CH
2-CO-O-(CH
2)4-CH
3(apricot)
• CH
3-CO-O-(CH
2)4-CH
3(banana)
• CH 3-CH 2-CH
2-CO-O-CH
2-CH
3(pineapple)
• H-CO-O-CH 2-CH
3(rum)
Examples of esters
• lower boiling points than carboxylic acids and alcohols (~ absence of hydrogen bonds) • less soluble in water than carboxylic acids• esters have a fruity smell•reactions : ester hydrolysis saponification = hydrolysis by a strong base →salt and alcohol →salts of long chain fatty acids are SOAPS polymerization →polyesters (from difunctional monomers)
Properties and reactions of esters
2.3. ANHYDRIDESR
1- CO- O- CO
- R 2 •acid → anhydride (acetic acid → acetic anhydride ) •organic, organic-inorganic examples• acetic formic anhydride• phtalic anhydride• "phosphoglycerate" (= phosphoric glyceric anhydride)
2.4. AMIDES
R-
CO- NH
2 •suffix : -amide (ethanamide) •-ic or -oic acid →-amide (acetamide ) • substituted -NH
2group:
N-alkyl...amide
•substituted amide groups are found in proteins (the peptide bond = "amide bond")• nitrogen atom contains an unshared pair of electrons → delocalization ⇒ amides are not basic • strong intermolecular H-bonds: amides are solids
• low MW amides are soluble in water• carboxylic acid + ammonia (or amine) →amide + water
2.5. ACYLHALIDES
R- CO- X
X = halogen
•acyl name + halide •e.g. acetyl chloride (= ethanoyl chloride) butyryl bromide (= butanoyl bromide)2.6. NITRILES R-
CººººN
•hydrocarbon + suffix: -nitrile oralkyl cyanide •e.g ethanenitrile or methyl cyanide butanenitrile or propyl cyanide • mostly toxic liquids
Exercise
• H 2N-CH 2-CH 2-CH
2-COOH
• CH
3-CO-CH
2-COOH
• CH
3-CH(OH)-CH
2-COOH
• CH 3-CH 2-CH
2-CO-O-CH
3 • CH
3-CO-COOH
• CH3-CH
2-O-CH
3 • CH
3-CO-CH
2-CH 3 • CH 3-(CH
2)14-COOH
• CH 3-CH 2-CH
2-COONa
• (CH 3-CH
2-COO)
2Ca • CH 3-CH
2-O-CO-H
Exercise
• C 6H
5-CO-Cl
• H-CO-O-CH 2-CH 3 • CH
2=CH-CN
• H-CO-NH 2 • CH 3-CH
2-CO-NH-CH
2-CH 3
Derivatives Documents PDF, PPT , Doc