Organic Chemistry
9th Edition
ISBN: 9781305080485
Author: John E. McMurry
Publisher: Cengage Learning
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Textbook Question
Chapter 26.SE, Problem 25MP
The chloromethylated polystyrene resin used for Merrifield solidphase peptide synthesis is prepared by treatment of polystyrene with chloromethyl methyl ether and a Lewis acid catalyst. Propose a mechanism for the reaction.
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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.
CH,OCH,CI
SnCl,
CH,CI
The chloromethylated polystyrene resin used for Merrifield solid-phase peptide synthesis is prepared by treatment of polystyrene with chloromethylmethyl ether and a Lewis acid catalyst. The
reaction involves the following steps:
1. Reaction of the ether with the Lewis acid to form cation 1;
2. Electrophilic aromatic substitution to form resonance stzbilized cation 2:
3. Deprotonation yields aromatic ether 3:
4. Protonation to žorm protonated ether 4;
5. Displacement by chloride ion to form the final product
Write out the mechanism on a separate sheet of paper and then draw the structure of the resonance contributors of the resonance stabilized cation 2.
• Use Rl groups to indicate the points where the polymer repeats. The R group tool is located in the charges and lone pairs drop-down menu.
• Draw one structure per sketcher. Add additional sketchers using the drop-down menu in the bottom right corner.
• Separate resonance structures using the symbol from the…
tert-Butoxycarbonyl azide was developed as a reagent for peptide synthesis at OWL's home institution, the University of Massachusetts, by Prof. L.A. Carpino. It is prepared by treating tert-butoxycarbonyl chloride with sodium azide. Propose a structure for the initially-formed intermediate in this reaction.
Chapter 26 Solutions
Organic Chemistry
Ch. 26.1 - How many of the -amino acids shown in Table 26-1...Ch. 26.1 - Prob. 2PCh. 26.1 - Prob. 3PCh. 26.2 - Hemoglobin has pI=6.8. Does hemoglobin have a net...Ch. 26.3 - Show how you could prepare the following -amino...Ch. 26.3 - What alkyl halides would you use to prepare the...Ch. 26.3 - Prob. 7PCh. 26.4 - There are six isomeric tripeptides that contain...Ch. 26.4 - Draw the structure of M-P-V-G, and indicate its...Ch. 26.5 - Prob. 10P
Ch. 26.5 - Prob. 11PCh. 26.6 - The octapeptide angiotensin II has the sequence...Ch. 26.6 - Prob. 13PCh. 26.6 - Prob. 14PCh. 26.6 - Give the amino acid sequence of hexapeptides that...Ch. 26.7 - Prob. 16PCh. 26.7 - Write all five steps required for the synthesis of...Ch. 26.10 - Prob. 18PCh. 26.SE - Identify the following amino acids:Ch. 26.SE - Prob. 20VCCh. 26.SE - Isoleucine and threonine are the only two amino...Ch. 26.SE - Prob. 22VCCh. 26.SE - Give the sequence of the following tetrapeptide:Ch. 26.SE - Prob. 24MPCh. 26.SE - The chloromethylated polystyrene resin used for...Ch. 26.SE - Prob. 26MPCh. 26.SE - Prob. 27MPCh. 26.SE - Prob. 28MPCh. 26.SE - Except for cysteine, only S amino acids occur in...Ch. 26.SE - Prob. 30APCh. 26.SE - Prob. 31APCh. 26.SE - Show the structures of the following amino acids...Ch. 26.SE - Prob. 33APCh. 26.SE - Using both three- and one-letter codes for amino...Ch. 26.SE - Prob. 35APCh. 26.SE - Show how you could use the acetamidomalonate...Ch. 26.SE - Prob. 37APCh. 26.SE - Show how you could prepare the following amino...Ch. 26.SE - Prob. 39APCh. 26.SE - Predict the product of the reaction of valine with...Ch. 26.SE - Prob. 41APCh. 26.SE - Prob. 42APCh. 26.SE - Propose two structures for a tripeptide that gives...Ch. 26.SE - Show the steps involved in a synthesis of...Ch. 26.SE - Prob. 45APCh. 26.SE - Prob. 46APCh. 26.SE - Prob. 47APCh. 26.SE - Which of the following amino acids are more likely...Ch. 26.SE - Leuprolide is a synthetic nonapeptide used to...Ch. 26.SE - The -helical parts of myoglobin and other proteins...Ch. 26.SE - Prob. 51APCh. 26.SE - Cytochrome c is an enzyme found in the cells of...Ch. 26.SE - Prob. 53APCh. 26.SE - Prob. 54APCh. 26.SE - Prob. 55APCh. 26.SE - What is the structure of a nonapeptide that gives...Ch. 26.SE - Oxytocin, a nonapeptide hormone secreted by the...Ch. 26.SE - Aspartame, a nonnutritive sweetener marketed under...Ch. 26.SE - Prob. 59APCh. 26.SE - Prob. 60APCh. 26.SE - Prob. 61APCh. 26.SE - Prob. 62AP
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