Organic Chemistry
9th Edition
ISBN: 9781305080485
Author: John E. McMurry
Publisher: Cengage Learning
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Chapter 29.SE, Problem 30MP
Interpretation Introduction
Interpretation:
The amino acid leucine is biosynthesized from α-ketoisocaproate, which is itself prepared from α-ketoisovalerate by a multistep route that involves (1) reaction with acetyl CoA, (2) hydrolysis, (3) dehydration, (4) hydration, (5) oxidation, and (6) decarboxylation. Show the steps in the transformation, and propose a mechanism for each.
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Pyruvate carboxylase is thought to activate CO2 by ATP, through formation of carboxyphosphate as an intermediate. Propose a mechanism for the formation of this intermediate.
The vitamin Niacin is used to form nicotinamide adenosine dinucleotide, which readily shuttles between its oxidized (NAD+) and reduced (NADH) forms. The latter serves as a cellular equivalent to NaBH4. The essential portions of the structures are shown below. Outline a mechanism for the cellular conversion of pyruvate to lactate. (Note: like NaBH4, NADH cannot reduce carboxylic acid carbonyls).
A variation of the acetamidomalonate synthesis can be used to synthesize serine. The process involves the following steps:
Ethoxide ion deprotonates diethyl acetamidomalonate, forming enolate anion 1;
Enolate anion 1 makes a nucleophilic attack on formaldehyde, forming tetrahedral intermediate 2;
Protonation of the oxyanion forms alcohol 3;
Acid hydrolysis yields dicarboxyamino alcohol 4;
Decarboxylation leads to the final amino acid.
Write out the mechanism on a separate sheet of paper, and then draw the structure of tetrahedral intermediate 2.
You do not have to consider stereochemistry.
You do not have to explicitly draw H atoms.
Do not include lone pairs in your answer. They will not be considered in the grading.
Draw carboxyl and amino groups in their uncharged forms.
Chapter 29 Solutions
Organic Chemistry
Ch. 29.1 - Prob. 1PCh. 29.3 - Write the equations for the remaining passages of...Ch. 29.3 - Prob. 3PCh. 29.4 - Write a mechanism for the dehydration reaction of...Ch. 29.4 - Evidence for the role of acetate in fatty-acid...Ch. 29.4 - Does the reduction of acetoacetyl ACP in step 6...Ch. 29.5 - Prob. 7PCh. 29.5 - Look at the entire glycolysis pathway, and make a...Ch. 29.6 - Prob. 9PCh. 29.7 - Prob. 10P
Ch. 29.7 - Write mechanisms for step 2 of the citric acid...Ch. 29.7 - Prob. 12PCh. 29.8 - Prob. 13PCh. 29.9 - Write all the steps in the transamination reaction...Ch. 29.9 - What -keto acid is formed on transamination of...Ch. 29.9 - Prob. 16PCh. 29.SE - Prob. 17VCCh. 29.SE - Identify the following intermediate in the citric...Ch. 29.SE - The following compound is an intermediate in the...Ch. 29.SE - Prob. 20VCCh. 29.SE - In the pentose phosphate pathway for degrading...Ch. 29.SE - Prob. 22MPCh. 29.SE - One of the steps in the pentose phosphate pathway...Ch. 29.SE - One of the steps in the pentose phosphate pathway...Ch. 29.SE - Prob. 25MPCh. 29.SE - Prob. 26MPCh. 29.SE - Prob. 27MPCh. 29.SE - Prob. 28MPCh. 29.SE - Prob. 29MPCh. 29.SE - Prob. 30MPCh. 29.SE - Prob. 31MPCh. 29.SE - Prob. 32APCh. 29.SE - Prob. 33APCh. 29.SE - Prob. 34APCh. 29.SE - Prob. 35APCh. 29.SE - Prob. 36APCh. 29.SE - Prob. 37APCh. 29.SE - Prob. 38APCh. 29.SE - Prob. 39APCh. 29.SE - Prob. 40APCh. 29.SE - Prob. 41APCh. 29.SE - Prob. 42APCh. 29.SE - Prob. 43APCh. 29.SE - Prob. 44APCh. 29.SE - Prob. 45APCh. 29.SE - Prob. 46APCh. 29.SE - Prob. 47APCh. 29.SE - Prob. 48APCh. 29.SE - Prob. 49APCh. 29.SE - Prob. 50APCh. 29.SE - In glycerol metabolism, the oxidation of...Ch. 29.SE - Prob. 52APCh. 29.SE - Prob. 53APCh. 29.SE - Prob. 54APCh. 29.SE - In step 7 of fatty-acid biosynthesis (Figure...Ch. 29.SE - Prob. 56AP
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