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Organic chemistry II
Zdeněk Friedl
Chapter 22
Acyl derivatives II
Solomons & Fryhle: Organic
Chemistry 8th Ed., Wiley 2004
Nitriles, substituent derivatives of carboxylic acids,
carbonic acid derivatives
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reaction scheme of nitriles, preparation, reactions
α-amino acids, stereochemistry, nomenclature
physical properties, isoelectric point
synthesis of α-amino acids
peptides, polyamides, lactams
α-halogeno acids, preparation, reactions
γ- and δ-hydroxy acids, lactones, polyesters
carbonic acid derivatives, phosgene, urea
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AN
The reaction scheme of nitriles
H
α
δ+
R CH C
H
+
δ−
N|
|Nu
B
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The electrostatic potential map of acetonitrile
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Preparation of nitriles I
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SN2
Preparation of nitriles II
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Reactions of nitriles I
acid-catalyzed hydrolysis of nitriles
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Reactions of nitriles II
base-catalyzed hydrolysis of nitriles
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Reactions of nitriles III
synthesis of 3° alcohols by organomagnesium or lithium reagents
The creating ketone is more reactive than initial nitrile a immediately reacts with
other molecule of R’-MgBr and the 3° alcohol RR’R’C-OH is the final product
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Reactions of nitriles IV
the reduction of nitriles to aldehydes by DIBAL
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α-Amino acids found in proteins I
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α-Amino acids found in proteins II
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α-Amino acids found in proteins III
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Stereochemistry of α-amino acids
Enantiomeric
α-amino acids
Diastereomeric
α-amino acids
COOH
COOH
H2N C H
CH2OH
L-Serine
(S)-2-amino-3hydroxypropanoic acid
N
o
m
e
n
k
H2N C H
H3C
C H
C2H5
Isoleucine
(2S,3S)-2-amino-3methylpentanoic acid
COOH
H2N C H
H C OH
CH3
Threonine
(2S,3R)-2-amino-3hydroxybutanoic acid
Among 20 α-AA 19 are chiral and 18 from them are of (S)-configuration.
configuration.
Only L-Cysteine is of (R) configuration.
configuration.
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Synthesis of α-amino acids I
ammonolysis α-halogeno acids
STRECKER synthesis
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Synthesis of α-amino acids II
phthalimide method (modification of the GABRIEL synthesis )
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The Annunciation of the Virgin Mary
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Synthesis of α-amino acids III
phthalimide – α-bromomalonate synthesis
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pI
A titration curve for alanine
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pI
Isoelectric point of amino acids
Calculation of isoelectric point of alanine
pKa
CH3 CH2 COOH
4.91
pI = (pKa1 + pKa2) / 2
= ( 2.34 + 9.69 ) / 2
CH3
CH2 NH2
10.75
= 6.02
CH3 CH COOH
CH3-CH-COO|
NH3+
2.34
NH2
CH3
CH COOH
9.69
NH2
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Polyamides I
polycondenzation of α-amino acids a proteins
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The nomenclature of peptides
O
H2N CH2
CH3
C NH CH COOH
glycyl-L-alanine Gly-Ala
CH3 O
H2N CH C NH CH2 COOH
L-alanyl-glycine
Ala-Gly
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Lactams
β-, γ-, δ- and ε-amino acids undergo intramolecular dehydration
a β-, γ-, δ- and ε-lactams
O
NH
ε-caprolactam
Physiological active compounds
condensed β-lactams
ANTIBIOTICS
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Polyamides II
Nylon 6,6 (Nylon)
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Polyamides III
Nylon 6 (Silon)
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Preparation of α-halogeno carboxylic acids
HELL-VOLHARD-ZELINSKII reaction (Br,Cl)
O
P + Br2
(PBr3)
R CH2 C
O
R CH2 C
OH
δ−
Br
OH
+
R CH C
O
CH C
Br
O
+
Br
R CH C
Br
R
- HBr
O
CH C
Br
Br
R
OH
+
Br
δ+
Br
H
R
Br
O
CH C
R CH2 C
OH
Br
O
+
OH
R CH2 C
Br
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AN(E)
Reaction of C=O compounds with cryptobases
addition of R:ZnBr reagents
REFORMATSKY reaction
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Lactones
γ- and δ-hydroxy acids undergo intramolecular esterification a γ- and δ-lactones
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Physiological active compounds
α,β-unsaturated γ-lactones
Butenolid
H3C
influences germination of coniferous trees
O
O
O
a it forms by thermal decomposition of cellulose
during a forest fire
OH
O
O
O
Patulin
antibiotics
a metabolite of many mushrooms
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Polyesters I
Poly(ethylene terephthalate), PET
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Polyesters II
chemical recycling of poly(ethylene terephthalate), PET
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Carbonic acid derivatives
H2CO3 g H2O + CO2
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Carbonic acid derivatives – PHOSGENE I
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Carbonic acid derivatives – PHOSGENE II
Ar-NH2 + COCl2 g Ar-N=C=O + 2 HCl
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Carbonic acid derivatives – PHOSGENE III
polyurethanes
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Carbonic acid derivatives – UREA I
At present the urea is made as follows:
CO2 + 2 NH3 g [H2N-COONH4] g H2N-CO-NH2 + H2O
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Carbonic acid derivatives – UREA II
synthesis of barbituric acid
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Physiological active compounds
5,5-dialkylbarbituric acids
Barbiturates
HYPNOTICA
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