EBK ORGANIC CHEMISTRY
8th Edition
ISBN: 8220102744127
Author: Bruice
Publisher: PEARSON
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Textbook Question
Chapter 21, Problem 78P
Propose a mechanism for the rearrangement of the thiazoline obtained from the reaction of Ed man's reagent with a peptide to a PTH-amino acid (page 1014). (Hint: Thioesters are very reactive toward nucleophiles.)
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(a) Isoleucine has been prepared by the following sequence of reactions. Give the structure of compounds A through D isolated as intermediates in this synthesis.(b) An analogous procedure has been used to prepare phenylalanine. What alkyl halide would you choose as the starting material for this synthesis?
The reaction of ninhydrin with an -amino acid occurs in several steps
(a) The first step is loss of water to give a triketone. Show the mechanism of the reaction and the structure of the triketone.(b) The second step is formation of an imine by reaction of the amino acid with the triketone. Show its structure. (c) The third step is a decarboxylation. Show the structure of the product and the mechanism of the decarboxylation reaction.
(d) The fourth step is hydrolysis of an imine to yield an amine and an aldehyde. Show the
structures of both products.
(e) The final step is formation of the purple anion. Show the mechanism of the reaction
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Chapter 21 Solutions
EBK ORGANIC CHEMISTRY
Ch. 21.1 - a. Explain why, when the imidazole ring of...Ch. 21.2 - a. Which isomer(R)-alanine or (S)-alanineis...Ch. 21.2 - Prob. 4PCh. 21.3 - Prob. 5PCh. 21.3 - Prob. 6PCh. 21.3 - Draw the predominant form for glutamate in a...Ch. 21.3 - a. Why is the pKa of the glutamate side chain...Ch. 21.4 - Calculate the pI of each of the following amino...Ch. 21.4 - a. Which amino acid has the lowest pI value? b....Ch. 21.4 - Prob. 12P
Ch. 21.4 - Prob. 13PCh. 21.4 - Explain why the pI of lysine is the average of the...Ch. 21.5 - What aldehyde is formed when valine is treated...Ch. 21.5 - Prob. 16PCh. 21.5 - Prob. 17PCh. 21.5 - Prob. 18PCh. 21.5 - Prob. 19PCh. 21.6 - Why is excess ammonia used in the preceding...Ch. 21.6 - Prob. 21PCh. 21.6 - What amino acid is formed using the...Ch. 21.6 - Prob. 23PCh. 21.6 - What amino acid is formed when the aldehyde used...Ch. 21.7 - Esterase is an enzyme that catalyzes the...Ch. 21.8 - Draw the tetrapeptide Ala-Thr-Asp-Asn and indicate...Ch. 21.8 - Draw the resonance contributors of the peptide...Ch. 21.8 - Which bonds in the backbone of a peptide can...Ch. 21.9 - An opioid pentapeptide has the following...Ch. 21.9 - What is the configuration about each of the...Ch. 21.9 - Glutathione is a tripeptide whose function is to...Ch. 21.10 - What dipeptides would be formed by heating a...Ch. 21.10 - Suppose you are trying to synthesize the dipeptide...Ch. 21.10 - Show the steps in the synthesis of the...Ch. 21.10 - a. Calculate the overall yield of bradykinin when...Ch. 21.11 - Show the steps in the synthesis of the...Ch. 21.13 - Prob. 37PCh. 21.13 - In determining the primary structure of insulin,...Ch. 21.13 - A decapeptide undergoes partial hydrolysis to give...Ch. 21.13 - Explain why cyanogen bromide does not cleave on...Ch. 21.13 - Indicate the peptides produced from cleavage by...Ch. 21.14 - Prob. 43PCh. 21.14 - Three peptides were obtained from a trypsin...Ch. 21.14 - Prob. 45PCh. 21.15 - How would a protein that resides in the nonpolar...Ch. 21.16 - a. Which would have the greatest percentage of...Ch. 21.17 - When apples that have been cut are exposed to...Ch. 21 - Glycine has pK2 values of 2.34 and 9.60. At what...Ch. 21 - Prob. 50PCh. 21 - A titration curve is a plot of the pH of a...Ch. 21 - Prob. 52PCh. 21 - Aspartame (its structure is on page 1007) has a pl...Ch. 21 - Draw the form of aspartate that predominates at...Ch. 21 - Show how phenylalanine can be prepared by...Ch. 21 - A professor was preparing a manuscript for...Ch. 21 - What aldehydes are formed when the following amino...Ch. 21 - Prob. 58PCh. 21 - Determine the amino acid sequence of a polypeptide...Ch. 21 - Prob. 60PCh. 21 - Prob. 61PCh. 21 - Which is the more effective buffer at...Ch. 21 - Identify the location and type of charge on the...Ch. 21 - Draw the product obtained when a lysine side chain...Ch. 21 - After the polypeptide shown below was treated with...Ch. 21 - Treatment of a polypeptide with 2-mercaptoethanol...Ch. 21 - Show how aspartame can be synthesized using DCCD.Ch. 21 - -Amino acids can be prepared by treating an...Ch. 21 - Reaction of a polypeptide with carboxypeptidase A...Ch. 21 - a. How many different octapeptides can be made...Ch. 21 - Glycine has pKa values of 2.3 and 9.6. Do you...Ch. 21 - A mixture of 15 amino acids gave the fingerprint...Ch. 21 - Write the mechanism for the reaction of an amino...Ch. 21 - Prob. 74PCh. 21 - Show how valine can be prepared by a. a...Ch. 21 - The primary structure of -endorphin, a peptide...Ch. 21 - A chemist wanted to test his hypothesis that the...Ch. 21 - Propose a mechanism for the rearrangement of the...Ch. 21 - A normal polypeptide and a mutant of the...Ch. 21 - Determine the amino acid sequence of a polypeptide...
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