Questions and Answers of Organic Chemistry 4th

What enzyme cofactor is associated with transamination?
Predict the splitting patterns for each proton in the following molecules: (a) CHBr2CH3 (d) 유 || CH3CHCOCH₂CH3 CH3 (b) CH3OCH₂CH₂Br (e) CH3CH₂COCHCH3 CH3 (c) CICH₂CH₂CH₂CI (f)
Show the products of each of the following reactions: (a) (b) (c) || CH3CH₂CH₂CH₂CH₂CSCOA Product of (a) + H₂O Product of (b) FAD FADH2 Acyl-CoA dehydrogenase Enoyl-CoA hydratase NAD+
What substance is the starting point of the citric acid cycle, reacting with acetyl CoA in the first step and being regenerated in the last step?
List the sequence of intermediates involved in the catabolism of glycerol from hydrolyzed fats to yield acetyl CoA.
Another step in gluconeogenesis (see Problem 17.31) is the conversion of oxaloacetate to phosphoenolpyruvate by decarboxylation phosphorylation. Tell what kind of reaction is occurring, and suggest a
The amino acid tyrosine is metabolized by a series of steps that include the following transformations. Propose a mechanism for the conversion of fumaroylacetoacetate into fumarate plus acetoacetate.
What is the structure of the α-keto formed by transamination of each of the following amino acids?(a) Valine(b) Phenylalanine(c) Methionine
Many drugs function by interfering with metabolic pathways. The anticancer drug methotrexate, for instance, inhibits the dihydrofolate reductase enzyme that catalyzes the following reactions:What
Methylation of tetrahydrofolate produces a cofactor called 5-methyltetrahydrofolate that is used in the conversion of homocysteine to methionine. Propose a mechanism for this reaction.
In addition to transferring a methyl group, tetrahydrofolate can also transfer a formaldehyde group, a process that is critical for the biosynthesis of thymidine. Draw a mechanism for incorporation
Write representative structures for the following:(a) A fat(b) A vegetable oil(c) A steroid
β-Glucose has the following structure. Identify the chirality centers in β-glucose, and tell how many stereoisomers of glucose are possible. НО НО CH₂OH ОН -ОН OH B-Glucose
How would you prepare the following alkyl halides from the appropriate alcohols? (a) CI CH3CCH3 CH3 CH3 ī CH3CHCH₂CHCH3 (b) Br (c) CH3 T BrCH₂CH₂CH₂CH₂CHCH3 (d) CH3 CI I
What substitution products would you expect to obtain from the following reactions? (a) (c) Br T CH3CH₂CHCH3 + LII CH₂Br + NaCN ? (b) CH3 T CH3CHCH₂CI + HS™ ?
Write the product you would expect from reaction of each of the following alkyl halides with(i) Na+ -SCH3(ii) NaOH (yellow-green = Cl): (a) (b) (c)
Assign R or S configuration to the following molecule, write the product you would expect from SN2 reaction with NaCN, and assign R or S configuration to the product (red = O, yellow-green = Cl):
Assign configuration to the following substrate, and show the stereochemistry and identity of the product you would obtain by SN1 reaction with H2O (reddish brown = Br):
Ignoring double-bond stereochemistry, what products would you expect from elimination reactions of the following alkyl halides? (a) Br CH3 | | CH3CH2CHCHCH3 (b) CH3 CI CH3 |
Name the following alkyl halides: (a) H3C Br Br | | || CH3CHCHCHCH₂CHCH3 CH3 (d) CH₂Br CH3CH₂CHCH₂CH₂CH3 (b) I CH3CH=CHCH2CHCH3 (e) CICH₂CH₂CH₂C=CCH₂Br (c) Br CI CH3 |
Draw structures corresponding to the following names:(a) 2-Chloro-3,3-dimethyl hexane(b) 3,3-Dichloro-2-methyl hexane(c) 3-Bromo-3-ethyl pentane(d) 2-Bromo-5-chloro-3-methylhexane
Alkane chlorination can occur at any position in the alkane chain. Draw and name all monochloro products you might obtain from radical chlorination of 3-methylpentane. Which, if any, are chiral?
Show the products obtained from addition of CH3MgBr to the following carbonyl compounds: (a) (b) (c) || CH3CH₂CH₂CCH₂CH3
Predict the products you would expect from the following reactions. Indicate the major product in each case. (a) H3C OH TL CH3CHCCH₂CH3 T CH3 H₂SO4 (b) OH I CH3CH₂CH₂CCH3 CH3 H₂SO4
How might you prepare the following substances by using nucleophilic substitution reactions?(a) CH3CH2CH2CH2OH(b) (CH3)2CHCH2CH2N3
What product would you expect to obtain from the SN2 reaction of (S)-2 bromohexane with sodium acetate, CH3CO2Na? Show the stereochemistry of both product and reactant.
What alcohols might the following alkenes be made from? (a) CH3 CH3 (b) CH3CH₂CH=CHCH₂CH₂CH3
What effect would the following changes have on the rate of the SN1 reaction of tert-butyl alcohol with HBr?(a) The HBr concentration is tripled.(b) The HBr concentration is halved, and the
Name the following ethers by IUPAC rules: (a) (c) CH3 CH3 LL. CH3CHOCHCH3 Br LOCH 3 (b) (d) -OCH₂CH₂CH3 CH3 T CH3CHCH₂OCH₂CH3
What product would you expect from the SN1 reaction of (S)-3-methyloctan-3-ol [(S)-3-hydroxy-3-methyloctane] with HBr? Show the stereochemistry of both starting material and product.
Show how you could prepare the following substances from propan-1-ol: (a) O || CH3CH₂CH (b) O CH3CH₂COH (c) CH3CH₂CH₂O Na+ (d) CH3CH₂CH₂Cl
What effect on the rate of an E1 reaction of 2-chloro-2-methylpropane would you expect if the concentration of the alkyl halide tripled?
Predict the product(s) of the following transformations: (a) (c) CH₂OH Periodinane CH3 Ọ H₂C=CHCHCH₂COCH 1. LIAIH4 2. H₂O ? ? (b) (d) CH3 I OCH₂CHCH3 H₂C-CHCH₂CH3 HBr HBr ? ?
Show how you could prepare the following substances from cyclohexanol: (a) (b) -Br (c) (d)
Draw structures corresponding to the following IUPAC names:(a) 2,3-Dichloro-4-methylhexane(b) 4-Bromo-4-ethyl-2-methylhexane(c) 3-Iodo-2,2,4,4-tetramethylpentane
Predict the likely products of reaction of the following ethers with HI: (a) CH3 T CH3CH₂OCHCH3 (b) CH3 CH3CCH₂OCH3 CH3
Draw and name the monochlorination products you might obtain by reaction of 2-methylpentane with Cl2. Which of the products are chiral?
Describe the effects of the variables on both SN2 and SN1 reactions:(a) Substrate structure(b) Leaving group
What carbonyl compounds would you reduce to prepare the following alcohols? List all possibilities. (a) CH3 CH3CH₂CH₂CH₂CCH₂OH CH3 (b) H3C OH CH3C-CHCH3 H3C (c) OH CHCH₂CH3
Which ion in each of the following pairs is a better leaving group?(a) F- or Br-(b) Cl- or NH2-(c) OH- or I-
Which alkyl halide in each of the following pairs will react faster in an SN2 reaction with OH-?(a) Bromobenzene or benzyl bromide, C6H5CH2Br(b) CH3Cl or (CH3)3CCl(c) CH3CH=CHBr or H2C=CHCH2Br
When 4-chlorobutane-1-thiol is treated with a strong base such as sodium hydride, NaH, tetrahydrothiophene is produced. Suggest a mechanism for this reaction. CICH2CH2CH2CH,SH NaH Ether S + H₂ H₂
Why can’t the Williamson ether synthesis be used to prepare diphenyl ether? Diphenyl ether
But-2-ene-1-thiol is a component of skunk spray. How would you synthesize this substance from but-2-en-1-ol? From methyl but-2-enoate, CH3CH=CHCO2CH3? More than one step is required in both instances.
Tert-Butyl ethers react with trifl uoroacetic acid, CF3CO2H, to yield an alcohol and 2-methylpropene. Tell what kind of reaction is occurring, and propose a mechanism. CH3 CH3 CH3 CF3CO2H + H3C H3C
How would you prepare the following compounds from 2-phenylethanol?(a) Benzoic acid(b) Ethylbenzene(c) 1-Bromo-2-phenylethane(d) Phenylacetic acid (C6H5CH2CO2H)(e) Phenylacetaldehyde (C6H5CH2CHO)
Give the structures of the major products you would obtain from reaction of phenol with the following reagents:(a) Br2 (1 mol)(b) Br2 (3 mol)(c) NaOH, then CH3I(d) Na2Cr2O7, H3O
Bombykol, the sex pheromone secreted by the female silkworm moth, has the formula C16H30O and the systematic name (10E,12Z)-hexadeca-10,12-dien-1-ol. Draw bombykol showing correct stereochemistry for
It’s found experimentally that a substituted cyclohexanol with an axial -OH group reacts with aqueous CrO3 more rapidly than its isomer with an equatorial -OH group. Draw both cis- and
Because all hamsters look pretty much alike, pairing and mating is governed by chemical means of communication rather than by physical attraction. Investigations have shown that dimethyl disulfide,
Reduction of butan-2-one with NaBH4 yields butan-2-ol. Explain why the product is chiral but not optically active. CH3CCH₂CH3 Butan-2-one
Nonoxynol 9 is a potent spermicide made by reacting ethylene oxide with p-nonylphenoxide. Propose a mechanism for this multistep reaction.
Methyl phenyl ether can be cleaved to yield iodomethane and lithium phenoxide when heated with LiI. Propose a mechanism for this reaction.
Captopril is a drug commonly used to treat high blood pressure and heart failure. It functions by decreasing the concentration of chemicals that constrict the blood vessels, so blood flows more
At equilibrium in aqueous solution, D-fructose consists of 70% β-pyranose, 2% α-pyranose, 23% β-furanose, and 5% α-furanose forms. Draw all four.
Human and horse insulin (see Problem 16.44) differ in primary structure at two amino acids: at the 9th position in one chain (human has Ser and horse has Gly) and at the 30th position in the other
What anticodon sequences of tRNAs are coded by each of the codons in Problem 16.37?Problem 16.37What amino acids do the following ribonucleotide codons code for?(a) AAU(b) GAG(c) UCC(d) CAU(e) ACC
Which nitrogen atom in imidazole (Problem 12.16) is more basic according to the following electrostatic potential map? Why?Problem 12.16The five-membered heterocycle imidazole contains two nitrogen
The following 1H NMR resonances were recorded on a spectrometer operating at 300 MHz. Convert each into δ units.(a) CHCl3, 2180 Hz(b) CH3Cl, 915 Hz(c) CH3OH, 1040 Hz(d) CH2Cl2, 1590 Hz
Assign R or S configuration to the chirality centers in the following molecules: (a) HOH (b) CI H (c) H OCH3 HOCH2 CO2H
One enantiomer of lactic acid is shown below. Is it R or S? Draw its mirror image in the standard tetrahedral representation. CO2H С. Н он CH3
Tell whether the following Newman projection of 2-chlorobutane is R or S. H. H3C CI H CH3 H
Draw a Newman projection that is enantiomeric with the one shown in Problem 6.47.Problem 6.47Tell whether the following Newman projection of 2-chlorobutane is R or S. H. H3C CI H CH3 H
What is the stereochemical configuration of the enantiomer of (2S,4R)-dibromooctane?
Draw a Newman projection of meso-tartaric acid.
Draw Newman projections of (2R,3R)- and (2S,3S)-tartaric acid, and compare them to the projection you drew in Problem 6.49 for the meso form.
Draw the two cis–trans stereoisomers of 1,2 dimethyl cyclopentane, assign R,S configurations to the chirality centers, and indicate whether the stereoisomers are chiral or meso.
Alkenes undergo reaction with peroxycarboxylic acids to give epoxides. For example, cis-but-2-ene gives 2,3-epoxybutane: H3C Н Н C=C CH3 Н RCO3H CH3CH-CHCH3 2,3-Epoxybutane
We said in Section 4.9 that an allylic carbocation is stabilized by resonance. Draw resonance structures to account for the similar stabilization of a benzylic carbocation. + CH₂ A benzylic
Hydroxide ion reacts with chloromethane in a single step according to the following equation но: + Н C-CI H/ Н НО-С Н Н H :CI:
If a reaction has Eact = 15 kJ/mol, is it likely to be fast or slow at room temperature? Explain.
Formulate the reaction of benzene with 2-chloro-2-methylpropane in the presence of AlCl3 catalyst to give tert-butylbenzene
Sodium methoxide, NaOCH3, contains both ionic and covalent bonds. Indicate which is which.
Use the δ + / δ - convention to indicate the direction of expected polarity for each of the bonds shown: (a) H3C-Br (d) H3C-SH (b) H3C-NH2 (e) H3C-MgBr (c) H₂N-H (f) H3C-F
Indicate which of the bonds in the following molecules are polar covalent, using the symbol δ + / δ -.(a) Br2(b) CH3Cl(c) HF(d) CH3CH2OH
Draw the product(s) obtained by conjugate addition of the following reagents to cyclohex-2-enone:(a) H2O(b) NH3(c) CH3OH(d) CH3CH2SH How can you explain the observation that the SN2 reaction of
Propose structures for molecules that meet the following descriptions:(a) A ketone, C5H10O(b) An aldehyde, C6H10O(c) A keto aldehyde, C6H10O2(d) A cyclic ketone, C5H8O
Predict the products of the reaction of the following substances with CrO3 in aqueous acid: (a) CH3CH₂CH₂CH₂CH (b) CH3 CH3CH,CH,CH, CHO CH3 (c)
How could you prepare hexan-2-one from the following starting materials? (a) (c) OH CH3CH₂CH₂CH₂CHCH3 CH3 CH3CH₂CH₂CH₂C=CH₂ (b) CH3CH₂CH₂CH₂C=CH
How might you use a Grignard reaction of an aldehyde or ketone to prepare the following molecule (red=O)?
Show how you might carry out the following transformation. (A protection step is needed.) OH HOCHSCHICHYLOCH, 2 HECHICHICHICCHS ? HCCH₂CH₂CH₂COCH3 HCCH₂CH₂CH₂CCH3 CH3
How might you prepare the following alcohols from an aldehyde or ketone? Show all possibilities. (a) H OH (b) CH₂CH₂OH (c) HO CH3 CH3
Show how the following molecule can be prepared from a carbonyl compound and an amine (blue=N):
The herbicide 2,4,5-T (2,4,5-trichlorophenoxyacetic acid) can be prepared by heating a mixture of 2,4,5-trichlorophenol and ClCH2CO2H with NaOH. Show the mechanism of the reaction.
The following compound was prepared by a conjugate addition reaction between an α, β-unsaturated ketone and an alcohol. Identify the two reactants. 0: H3C
Propose structures for molecules that meet the following descriptions:(a) A ketone, C5H10O(b) An aldehyde, C6H10O(c) A keto aldehyde, C6H10O2(d) A cyclic ketone, C5H8O
Judging from the following electrostatic potential maps, which kind of carbonyl compound has the more electrophilic carbonyl carbon atom, a ketone or an acid chloride? Which has the more nucleophilic
Identify the kinds of carbonyl groups in the following molecules (red=O, blue=N): (a) (b)
Draw structures corresponding to the following IUPAC names:(a) 3-Methylbutanal(b) 3-Methylbut-3-enal(c) 4-Chloropentan-2-one(d) Phenylacetaldehyde(e) 2,2-Dimethylcyclohexanecarbaldehyde(f)
How could you prepare pentanal from the following starting materials?(a) Pentan-1-ol(b) CH3CH2CH2CH2CO2H(c) Dec-5-ene
How would you carry out the following transformations? More than one step may be required.(a) Hex-3-ene → Hexan-3-one(b) Benzene → 1-Phenylethanol
Identify the nucleophile that has added to acetone to give the following products: (a) ОН CH3CHCH3 (b) ОН CH3CCH₂CH3 CH3 (c) NCH3 CH3CCH3 (d) OH CH3CCH3 SCH3
What product would you expect from nucleophilic addition of cyanide ion, CN-, to acetone, followed by protonation?
Compounds called cyanohydrins result from the nucleophilic addition of HCN to an aldehyde or ketone. Draw and the carbonyl compound that the following cyanohydrin was prepared from (red=O, blue=N):
Identify the different kinds of carbonyl functional groups in the following molecules: (a) CO₂H O || LOCCH3 Aspirin (b) CH3 CO₂CH3 H Cocaine LOCOC6H5 (c) CH₂OH T CHOH НО OH Ascorbic
What product would you expect from nucleophilic addition of methanol, CH3OH, to benzaldehyde under acidic conditions?
Give IUPAC names for the following structures: (a) (d) O CH3 CH3CHCCH2CH3 T CH3 (b) CHO H-C-OH CH₂OH (e) OH O |_____ || CH3CHCH₂CH (c) (f) OHC O CHO
In light of your answer to Problem 9.35, what stereochemistry would you expect the product from the reaction of phenylmagnesium bromide with butan-2-one to have?Problem 9.35Show the structures of the
Write the mechanism of the acid-catalyzed reaction of methanol with cyclohexanone to give a hemiacetal.
When an aldehyde or ketone is treated with a diol such as ethylene glycol (ethane-1,2-diol) and an acid catalyst, a cyclic acetal is formed. Draw the structure of the product you would obtain from

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