Organic Chemistry (8th Edition)
8th Edition
ISBN: 9780134042282
Author: Paula Yurkanis Bruice
Publisher: PEARSON
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Chapter 20, Problem 71P
Interpretation Introduction
Interpretation:
The mechanism for the rearrangement that converts an
Concept Introduction:
“Keto-enol tautomerism” is defined as the rearrangement to a
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The following three derivatives of succinimide are anticonvulsants and have found use in the treatment of epilepsy, particularly petit mal seizures.
Ph
Ph
`N'
`N'
ČH3
ČH3
Methsuximide
Ethosuximide
Phensuximide
Following is a synthesis of phensuximide.
CN
Ph
CN
Ph
CN
1. NaOH, H2O
2. HC, Н20
NaOEt
KCN
Ph-CHO
cOOEt
H
cOOEt
NC
COOEt
3. Нeat
Ethyl
cyanoacetate
(A)
(B)
Benzaldehyde
Ph
Ph
Ph
CH;NH2
НООС
СООН
Et0oC
COOEt
`N'
(C)
(D)
ČH3
Phensuximide
Methsuximide is formed by a similar pathway to that shown for phensuximide. Draw the structure of the compound that reacts with ethyl cyanoacetate in the synthesis of
methsuximide.
The following three derivatives of succinimide are anticonvulsants and have found use in the treatment of epilepsy, particularly petit mal seizures.
Ph.
Ph
`N'
ČH3
ČH3
Methsuximide
Ethosuximide
Phensuximide
Following is a synthesis of phensuximide.
CN
Ph
CN
Ph
CN
NaOEt
KCN
1. NaOH, H2O
Ph-CHO
2. HС, Н20
COOET
H
cOOEt
NC
COOEt
3. Нeat
Ethyl
cyanoacetate
(A)
(B)
Benzaldehyde
Ph.
Ph
Ph
CH3NH2
НООС
СООН
EtOOC
COOET
`N'
(C)
(D)
ČH3
Phensuximide
In the conversion of (B) to (C), draw the structure of the product of step 1.
When an α-hydroxy amide is treated with Br2 in aqueous NaOH under Hofmann rearrangement conditions, loss of CO2 occurs and a chain-shortened aldehyde is formed. The mechanism involves the following steps:
Base abstracts an acidic amide proton, yielding amide anion 1;
The amide anion reacts with bromine in an α-substitution reaction to give N-bromoamide 2.
Abstraction of the remaining amide proton by base gives a resonance-stabilized bromoamide anion 3;
Rearrangement occurs to yield isocyanate 4;
Water adds to the isocyanate to yield carbamic acid 5;
Elimination of CO2 yields carbinolamine 6;
Following proton transfer, expulsion of ammonia yields the final product aldehyde.
Write out the mechanism
and then draw the structures of bromoamide anion 3 and amide anion 1.
Chapter 20 Solutions
Organic Chemistry (8th Edition)
Ch. 20.1 - Prob. 1PCh. 20.2 - Prob. 2PCh. 20.2 - Prob. 3PCh. 20.3 - Prob. 4PCh. 20.3 - Prob. 5PCh. 20.3 - Prob. 6PCh. 20.4 - Prob. 7PCh. 20.4 - Prob. 8PCh. 20.5 - Prob. 9PCh. 20.5 - Prob. 10P
Ch. 20.5 - Prob. 11PCh. 20.6 - Prob. 12PCh. 20.6 - Prob. 13PCh. 20.6 - Prob. 14PCh. 20.7 - Prob. 15PCh. 20.8 - Prob. 16PCh. 20.9 - Prob. 18PCh. 20.10 - Prob. 20PCh. 20.10 - Prob. 21PCh. 20.10 - Prob. 22PCh. 20.11 - Prob. 23PCh. 20.11 - Prob. 24PCh. 20.12 - Prob. 25PCh. 20.12 - Prob. 26PCh. 20.14 - Prob. 28PCh. 20.15 - Prob. 29PCh. 20.15 - Prob. 30PCh. 20.16 - Prob. 31PCh. 20.17 - Prob. 32PCh. 20.18 - Refer to Figure 20.5 to answer the following...Ch. 20 - Prob. 34PCh. 20 - Prob. 35PCh. 20 - Prob. 36PCh. 20 - Prob. 37PCh. 20 - Prob. 38PCh. 20 - Prob. 39PCh. 20 - Prob. 40PCh. 20 - Prob. 41PCh. 20 - Prob. 42PCh. 20 - Prob. 43PCh. 20 - Prob. 44PCh. 20 - Prob. 45PCh. 20 - Prob. 46PCh. 20 - Prob. 47PCh. 20 - Prob. 48PCh. 20 - The 1H NMR spectrum of D-glucose in D2O exhibits...Ch. 20 - Prob. 50PCh. 20 - Prob. 51PCh. 20 - Prob. 52PCh. 20 - Prob. 53PCh. 20 - Prob. 54PCh. 20 - Prob. 55PCh. 20 - Prob. 56PCh. 20 - Prob. 57PCh. 20 - Prob. 58PCh. 20 - Prob. 59PCh. 20 - Prob. 60PCh. 20 - Prob. 61PCh. 20 - A hexose is obtained when the residue of a shrub...Ch. 20 - Prob. 63PCh. 20 - Prob. 64PCh. 20 - Prob. 65PCh. 20 - Prob. 66PCh. 20 - Prob. 67PCh. 20 - Prob. 68PCh. 20 - Prob. 69PCh. 20 - Prob. 70PCh. 20 - Prob. 71PCh. 20 - Prob. 72PCh. 20 - Prob. 73P
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