Questions and Answers of Organic Chemistry 4th

Using the equation given in Problem 13.34, calculate the energy required to effect the electronic excitation of buta-1,3-diene (λmax = 217 nm).Problem 13.34The energy of electromagnetic radiation in
Draw the following amino acids in their zwitterionic forms:(a) Serine(b) Tyrosine(c) Threonine
If the gene sequence -TAA-CCG-GAT- on DNA were miscopied during replication and became -TGA-CCG GAT-, what effect would the mutation have on the sequence of the protein produced?
The pathway for metabolism of a drug depends on the species doing the metabolizing. Coumarin, an anticoagulant, metabolizes to a toxic compound in rats but not in humans. How would the UV spectra
Dehydration of 1-methylcyclohexanol might lead to either of two isomeric alkenes, 1-methylcyclohexene or methylenecyclohexane. How could you use NMR spectroscopy (both 1H and 13C) to determine the
Convert the following tetrahedral representation of (S)-glyceraldehyde into a Fischer projection: HO H CHO CH₂OH (S)-Glyceraldehyde
The amino acid analysis data in Figure 15.2 indicate that proline is not easily detected by reaction with ninhydrin. Suggest a reason. Absorbance Asp 0.0 10.0 Thr Ser Ile Leu
When an unprotected -amino acid is treated with dicyclohexylcarbodiimide (DCC), a 2,5-diketopiperazine results. Explain. H₂N HR O An a-amino acid DCC R HJ H- -N H- N -H R A 2,5-diketopiperazine
The mosquito attractant oct-1-en-3-ol can be prepared by reduction of oct-1-en-3-one. How can UV spectroscopy be used to show when the reaction is complete?
If C-O single-bond stretching occurs at 1000 cm-1 A and C=O double-bond stretching occurs at 1700 cm-1, which of the two requires more energy? How does your answer correlate with the relative
Draw the product you would obtain from the acid-catalyzed reaction of-D-galactopyranose with ethanol.
Write an open-chain structure for a deoxyaldohexose.
Look at the structures of estradiol and ethynylestradiol, and point out the differences. What common structural feature do they share that makes both estrogens?
Write representative structures for the following:(a) A fat(b) A vegetable oil(c) A steroid
Identify the following bases, and tell whether each is found in DNA, RNA, or both: (a) (b) (c)
Write the structures of the following molecules:(a) Sodium stearate(b) Ethyl linoleate(c) Glyceryl dioleopalmitate
Cholesterol has the following structure. Tell whether the -OH group is axial or equatorial.
Eleostearic acid, C18H30O2, is a rare fatty acid found in tung oil. On oxidation with KMnO4, eleostearic acid yields 1 part pentanoic acid, 2 parts oxalic acid (HO2COCO2H), and 1 part nonanedioic
Draw the products you would obtain from treatment of cholesterol with the following reagents:(a) Br2(b) H2, Pd catalyst(c) CH3COCl, pyridine
If the average molecular weight of soybean oil is 1500, how many grams of NaOH are needed to saponify 5.00 g of the oil?
At what pH would you carry out an electrophoresis experiment if you wanted to separate a mixture of histidine, serine, and glutamic acid? Explain.
Draw structures of the following compounds. Which would you expect to have a higher melting point?(a) Glyceryl trioleate(b) Glyceryl monooleate distearate
Draw the structure of magnesium oleate, one of the components of bathtub scum.
What was the base sequence in the original DNA strand on which the mRNA sequence in Problem 16.15 was made?Problem 16.15What amino acid sequence is coded by the following mRNA base sequence?(5')
Eleostearic acid, C18H30O2, is a rare fatty acid found in tung oil. On oxidation with KMnO4, eleostearic acid yields 1 part pentanoic acid, 2 parts oxalic acid (HO2COCO2H), and 1 part nonanedioic
Stearolic acid, C18H32O2, yields oleic acid on catalytic hydrogenation over the Lindlar catalyst. Propose a structure for stearolic acid.
Spermaceti, a fragrant substance from sperm whales, was much used in cosmetics until it was banned in 1976 to protect whales from extinction. Chemically, spermaceti is cetyl palmitate, the ester of
Draw the products you would obtain from treatment of cholesterol with the following reagents:(a) Br2(b) H2, Pd catalyst(c) CH3COCl, pyridine
If the average molecular weight of soybean oil is 1500, how many grams of NaOH are needed to saponify 5.00 g of the oil?
Give codons for the following amino acids:(a) Th(b) Asp(c) Thr
Draw the complete structure of the deoxyribonucleotide sequence from which the codon in Problem 16.35 was transcribed.Problem 16.35Draw the complete structure of the ribonucleotide codon UAC. For
What amino acids do the following ribonucleotide codons code for?(a) AAU(b) GAG(c) UCC(d) CAU(e) ACC
From what DNA sequences were each of the mRNA codons in Problem 16.37 transcribed?Problem 16.37What amino acids do the following ribonucleotide codons code for?(a) AAU(b) GAG(c) UCC(d) CAU(e) ACC
Give an mRNA sequence that codes for synthesis of metenkephalin, a small peptide with morphine-like properties: Tyr-Gly-Gly-Phe-Met
Give a DNA gene sequence (sense strand) that will code for metenkephalin (Problem 16.42).Problem 16.42Give an mRNA sequence that codes for synthesis of metenkephalin, a small peptide with
Human and horse insulin both have two polypeptide chains with one chain containing 21 amino acids and the other containing 30 amino acids. How many nitrogen bases are present in the DNA to code for
What amino acid sequence is coded by the following mRNA sequence?CUA-GAC-CGU-UCC-AAG-UGA
What anticodon sequences of tRNAs are coded by the mRNA in Problem 16.46? What was the base sequence in the original DNA strand on which this mRNA was made? What was the base sequence in the DNA
Nandrolone is an anabolic steroid sometimes taken by athletes to build muscle mass. Compare the structures of nandrolone and testosterone, and point out their structural similarities.
Is the bicarbonate anion (HCO3) a strong enough base to react with methanol (CH3OH)? In other words, does the following reaction take place s written? (The pKa of methanol is 15.5; the pKa of H2CO3
Draw trans-1,2-dichlorocyclohexane in chair conformation, and explain why both chlorines must be axial or both equatorial.
Consider the energy diagram shown: Energy Reaction progress
What are the likely formulas of the following molecules?(a) AlCl?(b) CF2Cl?(c) NI?(d) CH?O
E or Z stereochemistry to the following compounds: (a) H3C C=C CH3CH2 CH₂OH CI (b) CI CH30 C=C CH₂CH3 CH₂CH₂CH3 (c) H H3C C=C CN CH₂NH2
Change the following old names to new, post-1993 names, and draw the structure of each compound:(a) 2,5,5-Trimethyl-2-hexene(b) 2,2-Dimethyl-3-hexyne(c) 2-Methyl-2,5-heptadiene(d)
Tamoxifen and clomiphene have similar structures but very different medical uses. Tell whether the alkene double bond in is E or Z.
Retin A, or retinoic acid, is a medication commonly used to reduce wrinkles and treat severe acne. How many different isomers arising from double bond isomerizations are possible? مع
Lycopene, the pigment that gives tomatoes their red color, is a terpene derived formally by the joining together of numerous isoprene units (see the Interlude in this chapter). Start at one end of
Line-bond structures appear to imply that there are two different isomers of 1,2-dibromobenzene, one with the bromine bearing carbon atoms joined by a double bond and one with the bromine-bearing
Draw and name the products you would expect to obtain by reaction of the following substances with Cl2 and FeCl3 (blue=N, reddish brown=Br): (a) (b)
There are three resonance structures of naphthalene, of which only one is shown. Draw the other two. Naphthalene
Show the structure of Teflon by drawing several repeating units. The monomer unit is tetrafluoroethylene, F2C=CF2.
Buta-1,3-diene reacts with Br2 to yield a mixture of 1,2- and 1,4-addition products. Show the structures of both.
Give the structure of all possible mono adducts of HCl and penta-1,3-diene, CH3CH-CH=CH=CH2.
There are three products that might form on reaction of toluene (methylbenzene) with Br2. Draw and name them.
Show the mechanism of the reaction of benzene with nitric acid and sulfuric acid to yield nitrobenzene.
Chlorination of o-xylene (o-dimethylbenzene) yields a mixture of two products, but chlorination of p-xylene yields a single product. Explain.
What products would you expect to obtain from the reaction of the following compounds with chloroethane and AlCl3?(a) Benzene (b) p-Xylene
What products would you expect to obtain from the reaction of benzene with the following reagents?(a) (CH3)3CCl, AlCl3 (b) CH3CH2COCl, AlCl3
What product(s) would you expect from sulfonation of the following compounds?(a) Nitrobenzene(b) Bromobenzene(c) Toluene(d) Benzoic acid(e) Benzonitrile
Draw resonance structures of the three possible carbocation intermediates to show how an acetyl group, CH3CPO, directs bromination toward the metal position.
Synthesize the following substances from benzene:(a) o-Bromotoluene(b) 2-Bromo-1,4 dimethylbenzene
Which of the following compounds are chiral? Label all chirality centers. (a) (d) H3C CH3 | | CH3CH₂CHCCH₂CH3 CH3 BrCH₂CHCHCH₂Br (b) H3C (e) Н- H3C 0 CH3 (c) (f) H3C Н H3C-- H CH3
The following structure represents a carbocation. Draw two resonance structures, indicating the positions of the double bonds.
In some cases, the Friedel–Crafts acylation reaction can occur intramolecularly, that is, within the same molecule. Predict the product of the following reaction: CI AICI 3 ?
The herbicide metolachlor is broadly used in the United States to control weeds but is being phased out in Europe because of possible environmental risks. Usually marketed under the name Dual,
Would you expect the trimethylammonium group to be an activating or deactivating substituent? Explain. N(CH3)3 Br Phenyltrimethylammonium bromide
Synthesis of the herbicide 2,4-D begins with chlorination of phenol followed by reaction of the product with NaOH and chloroacetic acid. Name the chlorinated intermediate, and use resonance
Draw structures corresponding to the following names:(a) m-Bromophenol(b) Benzene-1,3,5-triol(c) p-Iodonitrobenzene(d) 2,4,6 TrinitrTrinitrotolueneotoluene (TNT)(e) o-Aminobenzoic acid(f) 3-Methyl-2
Draw and name all isomeric bromomethyl benzenes.
What is the structure of the compound with formula C8H9Br that gives p-bromobenzoic acid on oxidation with KMnO4?
Show the steps involved in the Friedel–Crafts reaction of benzene with CH3Cl.
Carbocations generated by reaction of an alkene with a strong acid catalyst can react with aromatic rings in a Friedel-Crafts reaction. Propose a mechanism to account for the industrial synthesis of
Which of the following objects are chiral?(a) A basketball (b) A fork(c) A wine glass(d) A golf club(e) A monkey wrench(f) A snowflake
Which of the following compounds are chiral?(a) 2,4-Dimethylheptane(b) 5-Ethyl-3,3-dimethylheptane(c) cis-1,3-Dimethylcyclohexane(d) 4,5-Dimethylocta-2,6-diene
Draw chiral molecules that meet the following descriptions:(a) A chloroalkane, C5H11Cl(b) An alcohol, C6H14O(c) An alkene, C6H12(d) An alkane, C8H18
There are eight alcohols with the formula C5H12O. Draw them, and tell which are chiral.
Cholic acid, the major steroid found in bile, was found to have a rotation of +2.22° when a 3.00 g sample was dissolved in 5.00 mL of alcohol in a sample tube with a 1.00 cm pathlength. Calculate
Polarimeters are so sensitive that they can measure rotations to the thousandth of a degree, an important advantage when only small amounts of a sample are available. For example, when 7.00 mg of
Naturally occurring (S)-serine has [α]D = -6.83. What specific rotation do you expect for (R)-serine?
Rank the substituents in each of the following sets:(a) -H, -OH, -OCH3, -CH3(b) -Br, -CH3, -CH2Br, -Cl(c) -CH=CH2, -CH(CH3)2, -C(CH3)3, -CH2CH3(d) -CO2CH3, -COCH3, -CH2OCH3, -OCH3
Rank the substituents in each of the following sets: (a) CH3 -CH₂CCH3 CH3 (b) →→→SH -NH₂ -SO3H CH3 -CH₂CHCH₂CH3 -OCH₂CH₂OH -CH2CH2CH2CH2CH3
Convert the following skeletal structures into molecular formulas, and tell how many hydrogens are bonded to each carbon: (a) N Pyridine (b) Cyclohexanone (c) Indole N H
Which of the butane conformations you drew Problem 2.13 do you think is the most stable? Explain.Problem 2.13Looking along the C2-C3 bond of butane, there are two different staggered conformations
Propose skeletal structures for the following molecular formulas:(a) C4H8(b) C3H6O(c) C4H9Cl
Draw both cis and trans isomers of 1,2-dibromocyclobutane.
Draw cis-1,2-dichlorocyclohexane in a chair conformation, and explain why one chlorine must be axial and one equatorial.
Draw two chair structures for methylcyclohexane, one with the methyl group axial and one with the methyl group equatorial.
Is either of the following reactions likely to take place according to the pKa data in Table 1.2?(a)(b) HCN + CH3CO₂- Na+ Î Na+ CN + CH3CO₂H
Convert the following molecular model of ethane, C2H6, into a structure that uses wedged, normal, and dashed lines to represent three-dimensionality. Ethane
Convert the following molecular model of aspirin into a line-bond structure, and identify the hybridization of each carbon atom (gray = C, red = O, ivory = H). Aspirin (acetylsalicylic acid)
Electrostatic potential maps of (a) acetamide and (b) methylamine are shown. Which of the two has the more basic nitrogen atom? Which of the two has the more acidic hydrogen atoms?(a)(b)
Which of the following are likely to act as Lewis acids and which as Lewis bases? Which might act both ways? (a) CH3CH2OH (d) (CH3)3B (b) (CH3)2NH (e) H3C+ (c) MgBr2 (f) (CH3)3P
Convert the following line-bond structures into molecular formulas:(a)(b)(c) НО. Н н CH₂OH С. C НО C C=C OH Vitamin C (ascorbic acid)
Show how the species in part (a) can act as Lewis bases in their reactions with HCl, and show how the species in part (b) can act as Lewis acids in their reaction with OH-. (a) CH3CH₂OH, (CH3)2NH,
Imidazole, which forms part of the structure of the amino acid histidine, can act as both an acid and a base. Look at the electrostatic potential map of imidazole, and identify the most acidic
Draw a tetrahedral representation of tetrachloromethane, CCl4, using the standard convention of solid, dashed, and wedged lines.
Why do you think a C - H bond (109 pm) is longer than an H-H bond (74 pm)?
Draw both an electron-dot and a line-bond structure for acetaldehyde, CH3CHO.
Order the bonds in the following compounds according to their increasing ionic character: CCl4, MgCl2, TiCl3, Cl2O.

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