Interpretation:
The structure of the productwhich best represents the stereochemistry of the frog toxin is to be determined on the basis of the information given.
Concept introduction:
A chiral center is one which is attached to four different atoms or groups of atoms.
If a chiral molecule participates in a
The wedge and dash bonds may change in this case, but the overall configuration remains the same.
Natural L-glutamic acid has S configuration. If no reaction takes places at the chiral carbon atom of the amino acid, then its configuration is retained in the products formed.
Want to see the full answer?
Check out a sample textbook solutionChapter 26 Solutions
Organic Chemistry (Binghampton University)
- Leuprolide is a synthetic nonapeptide used to treat both endometriosis in women and prostate cancer in men. (a) Both C-terminal and N-terminal amino acids in leuprolide have been structurally modified. Identify the modifications. (b) One of the nine amino acids in leuprolide has d stereochemistry rather than the usual L. Which one? (c) Write the structure of leuprolide using both one- and three-letter abbreviations. (d) What charge would you expect leuprolide to have at neutral pH?arrow_forwardBradykinin is a linear nonapeptide released by blood plasma globulin in response to a wasp sting. It is a very potent pain-causing agent. Its constituent amino acids are 2R, G, 2F, 3P, S. The sue of 2,4-dinitrofluorobenzene and carboxypeptidase shows that both terminal residues are arginine. Partial hydrolysis of bradykinin gives the following di- and tripeptides: FS + PGF +PP + SPF + FR + RParrow_forwardShow that a phosphatidic acid is chiral, even though none of its fatty acids are chiral.Where is the asymmetric carbon atom?arrow_forward
- Write out a scheme for the resolution of the two enantiomers of theantiplatelet drug clopidogrel with 10-camphorsulfonic acid.arrow_forwardGlutathione (GSH) is a tripeptide that serves as a mild reducing agent to detoxify peroxides and maintain the cysteineresidues of hemoglobin and other red blood cell proteins in the reduced state. Complete hydrolysis of glutathione givesGly, Glu, and Cys. Treatment of glutathione with carboxypeptidase gives glycine as the first free amino acid released.Treatment of glutathione with 2,4-dinitrofluorobenzene (Sanger reagent, Problem 24-21, page 1246), followed bycomplete hydrolysis, gives the 2,4-dinitrophenyl derivative of glutamic acid. Treatment of glutathione with phenylisothiocyanate does not give a recognizable phenylthiohydantoin, however.(a) Propose a structure for glutathione consistent with this information. Why would glutathione fail to give a normalproduct from Edman degradation, even though it gives a normal product from the Sanger reagent followed byhydrolysis?(b) Oxidation of glutathione forms glutathione disulfide (GSSG). Propose a structure for glutathione disulfide, and…arrow_forwardEsterase is an enzyme that catalyzes the hydrolysis of esters. It hydrolyzes esters of L-amino acids more rapidly than esters of d-amino acids. How can this enzyme be used to separate a racemic mixture of amino acids?arrow_forward
- Brucine is a poisonous alkaloid obtained from Strychnos nux vomica, a tree that grows in India, Sri Lanka, and northern Australia. Write out a resolution scheme, which shows how a racemic mixture of phenylalanine can be resolved using brucine.arrow_forwardWrite out a scheme for the resolution of the two enantiomers of the antiplatelet drug clopidogrel with 10-camphorsulfonic acid.arrow_forwardGlutamic acid is a naturally occurring α-amino acid that contains acarboxy group in its R group side chain. (Glutamic acid isdrawn in its neutral form with no charged atoms, a form that does not actually exist at any pH.) a.) What form of glutamic acid exists at pH = 1?b.) If the pH is gradually increased, what form of glutamic acid exists afterone equivalent of base is added? After two equivalents? After threeequivalents?c.) Propose a structure of monosodium glutamate, the common flavorenhancer known as MSG.arrow_forward
- Threonine is a naturally occurring amino acid that has two stereogenic centers.a. Draw the four possible stereoisomers using wedges and dashed wedges.b. The naturally occurring amino acid has the 2S,3R configuration at its two stereogenic centers. Which structure does this correspond to?arrow_forwardIf the side chain of the amino add is a methyl group, the compound is referred to as alanine. What is the Cahn-Ingold-Prelog stereochemical descriptor for the chiral center in alanine? 1. It is a Z-stereocenter. 2. It is an S-stereocenter. 3. It is an E-stereocenter. 4. It is an R-stereocenter.arrow_forwardPredict the reactions ofcarbohydrates in acidic and basicsolutions, and with oxidizingand reducing agentsarrow_forward
- Organic ChemistryChemistryISBN:9781305580350Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. FootePublisher:Cengage LearningEBK A SMALL SCALE APPROACH TO ORGANIC LChemistryISBN:9781305446021Author:LampmanPublisher:CENGAGE LEARNING - CONSIGNMENT