Question: A racemic mixture with the constitution shown
A racemic mixture with the constitution shown below was isolated from the Maytenus apurimacensis plant that is used in South American folk medicine. In an effort to find another source of these compounds, all of the stereoisomers with this constitution have been made in the laboratory. Draw all possible stereoisomers of this compound and identify whether each one is chiral or achiral. Deduce which two stereoisomers were isolated from the plant. 
Transcribed Image Text:
но- -OH 0-CH3
> For each of the following reactions identify the arrow-pushing pattern that is being utilized: (a) (b) (다) он H. (d)
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> The following compound is an amino acid derivative (Chapter 25). In solution, molecules of this compound show a tendency to “stick” together, or self-assemble, via a series of intermolecular hydrogen bonds.
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> Each of 10 stereoisomeric sugar derivatives can be prepared via a multiple-step synthesis starting from either glucuronolactone 1D or its enantiomer 1L. Depending on the specific series of reactions used, the configuration at carbons 2, 3, and 5 can be s
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> Triphenylmethane dyes are among the first synthetic dyes developed for commercial use. A comparison of the structures of these compounds reveals that even small differences in structure can lead to large differences in color.15 The structures of three su
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> The following questions apply to the five compounds in the previous problem. a. Which compound is meso? b. Would an equal mixture of compounds b and c be optically active? c. Would an equal mixture of compounds d and e be optically active?
> Draw bond-line structures using wedges and dashes for the following compounds: CH Et Et H- -OH H- -OH но но но -H H- FOH H- -OH H- он но (a) ČH, (b) Me (c) Me Me Me H- -CI C- -H но но- (d) Me (e) Me
> Determine whether each of the following compounds is optically active or optically inactive: CH3 он Et но H. Ме Me- .CI H- он Me (a) H Me OH H CH, (Ь) (с) CH,CH, H. HO H H- он CH,OH CH, ČH, (d) (е) (f) (9) (h) I
> For each of the following pairs of compounds, determine the relationship between the two compounds: Me Me -CI CI- HO Me -H но (а) Me (b) (с) (d) CH, CH, Et Et H- -OH но- H- OH HO но H- -OH но- -H H- он H- -он но- H- OH но FH (е) ČH, ČH, (f) Me Me
> cis-1,3-Dimethylcyclobutane has two planes of symmetry. Draw the compound and identify both planes of symmetry.
> Each of the following compounds possesses a plane of symmetry. Find the plane of symmetry in each compound. In some cases, you will need to rotate a single bond to place the molecule into a conformation where you can more readily see the plane of symmetr
> (R)-Limonene is found in many citrus fruits, including oranges and lemons: For each of the following compounds identify whether it is (R)-limonene or its enantiomer, (S)-limonene: (a) (b) (c) (d)
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> Draw the enantiomer of each compound in the previous problem.
> Determine the configuration for every chiral center in each of the following compounds: OH он он он но- -H но -H HO H но—н H- OH H- -OH HO H HO H ČH,OH CH,OH CH,OH (a) (b) (c)
> Draw a plausible mechanism for each of the following transformations он Br conc. H2SO4 HBr heat (b) OH Он conc. HSO4 HBr HO. Br (d) heat
> Determine whether each statement is true or false: a. A racemic mixture of enantiomers is optically inactive. b. A meso compound will have exactly one nonsuperimposable mirror image. c. Rotating the Fischer projection of a molecule with a single chira
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> The specific rotation of l-alanine in water (at 25°C) is +2.8. A chemist prepared a mixture of l-alanine and its enantiomer, and 3.50 g of the mixture was dissolved in 10.0 mL of water. This solution was then placed in a sample cell with a pathlength of
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> Identify the number of stereoisomers expected for each of the following: Me он CI он Me (а) OH (b) Он (с) (d) (е) Но OH (f)
> Predict the major product for each of the following reactions. OH он ? ? HBr conc. H2SO4 heat (a) (b)
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> Carbon is not the only element that can function as a chiral center. In Problem 5.6 we saw an example in which a phosphorus atom is a chiral center. In such a case, the lone pair is always assigned the fourth priority. Using this information, assign the
> Assign the configuration of the chiral center in the following compound:
> Paclitaxel (marketed under the trade name Taxol) is found in the bark of the Pacific yew tree, Taxus brevifolia, and is used in the treatment of cancer: a. Draw the enantiomer of paclitaxel. b. How many chiral centers does this compound possess? он
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> Atorvastatin is sold under the trade name Lipitor and is used for lowering cholesterol. Annual global sales of this compound exceed $13 billion. Assign a configuration to each chiral center in atorvastatin: он он но. F
> Bogorol A is a natural product with the potential to fight antibiotic-resistant bacteria. Shown below is an intermediate that was used in a synthesis of bogorol A. Assign the configuration of the alkene unit as either E or Z. R. N. OMe Intermediate i
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> Determine whether each of the following allenes is chiral or achiral: H3C H3C CC=C CH, *CH3 C=C=c "CH,CH3 C=C=C CH3 (a) H (b) (c) (d) CH3
> Protease inhibitors are a class of anti-viral drugs that have had success in treating HIV/AIDS. The following molecules were synthesized as potential HIV protease inhibitors. Compound 1 was found to be an effective protease inhibitor, while compound 2 wa
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> In the field of chemical research, one area of interest is the study of how variations in structure, including stereochemical variations, affect the biological activity of natural products. (−)-Lariciresinol, shown on the right, is a na
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> An unknown compound with the molecular formula C6H13Cl is treated with sodium ethoxide to produce 2,3-dimethyl-2-butene as the major product. Identify the structure of the unknown compound.
> A common method for confirming the proposed structure and stereochemistry of a natural product is to synthesize the proposed structure and then compare its properties with those of the natural product. This technique was used to verify the structure of c
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> Levetiracetam is used for the treatment of seizures in patients with epilepsy. For patients who have a hard time swallowing the needed pills twice daily, relief is in sight now that the FDA has granted approval for the use of rapidly dissolving, porous t
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> In Chapter 24, we will see that amino acids (like the ones shown below) can be linked together to give short chains, called peptides, or longer chains (≈50–2000 amino acids linked together) called proteins. High-protei
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> Draw the enantiomer of each of the following compounds: он но 'N HO HO OH Albuterol (sold under the trade name Ventolin) Propranolol A beta blocker used in the treatment of hypertension Oxybutynin (c) Used to treat urinary and bladder disorders A bro
> Compound A and compound B are constitutional isomers with the molecular formula C4H9Cl. Treatment of compound A with sodium methoxide gives trans-2-butene as the major product, while treatment of compound B with sodium methoxide gives a different disubst
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> Consider the following tetra-substituted cyclohexane: a. Draw both chair conformations of this compound. b. Determine which conformation is more stable. c. At equilibrium, would you expect the compound to spend more than 95% of its time in the more st
> Determine whether the following compounds are constitutional isomers: H H. H3C CH CH H3C CH3 H
> Compare the three staggered conformations of ethylene glycol. The anti conformation of ethylene glycol is not the lowest energy conformation. The other two staggered conformations are actually lower in energy than the anti conformation. Suggest an explan
> Consider the structures of cis-1,2-dimethylcyclopropane and trans-1,2-dimethylcyclopropane: a. Which compound would you expect to be more stable? Explain your choice. b. Predict the difference in energy between these two compounds. A A
> For each pair of compounds below, determine whether they are identical compounds, constitutional isomers, or stereoisomers: CH,CH, CH CH, H. H,C- CH,CH, H CH,CH, (b) H (a) (c) (d) CH, CH, H H CH, CH, H CH, CH, (F) H CH, H CH, H (e) H CH, H. H H (g)
> trans-1,3-Dichlorocyclobutane has a measurable dipole moment. Explain why the individual dipole moments of the C−Cl bonds do not cancel each other to produce a zero net dipole moment. CI- trans-1,3-Dichlorocyclobutane
> Derivatives of griselimycin, a natural product isolated in the 1960s, are being investigated for the treatment of tuberculosis. For each of the highlighted substituents in the griselimycin derivative shown below, indicate the systematic name as well as t
> There are 18 constitutional isomers with the molecular formula C8H18. Without drawing all 18 isomers, determine how many of the isomers will have a parent name of heptane.
> Identify the major and minor product(s) that are expected for each of the following reactions. Br Br ? ? Naci NaOH DMSO (a) (b) Br ? I-BUOK DBN (c) (d) ? ? 1-BUOK NASH (e) (f) Br ? Br ? NaOH NaOE (g) (h) Br ? ? EIOH NaOH Heat (i) Br Br ? NaOMe NaOMe
> Below is the numbered skeleton of trans-decalin: Identify whether each of the following substituents would be in an equatorial position or an axial position: a. A group at the C-2 position, pointing UP b. A group at the C-3 position, pointing DOWN c.
> myo-Inositol is a polyol (a compound containing many OH groups) that serves as the structural basis for a number of secondary messengers in eukaryotic cells. Draw the more stable chair conformation of myo-inositol. OH но HO он HO,
> Consider the following two conformations of 2,3-dimethylbutane. For each of these conformations, use Table 4.6 to determine the total energy cost associated with all torsional strain and steric strain. CH, H- CH, H,C H CH3 CH H CH3 (a) (b) HCH, I I
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> Glucose (a sugar) is produced by photosynthesis and is used by cells to store energy. Draw the most stable conformation of glucose: OH но, O. HO OH OH Glucose
> Draw a Newman projection of the following compound as viewed from the angle indicated: CI Br CI Br
> For each of the following pairs of compounds, determine which compound is more stable (you may find it helpful to draw out the chair conformations): (b) (c) (d)
