(a) The iSH group is sometimes called the mercapto group. 6-Mercaptopurine is used in the treatment of acute leukemia. Write its structure. (b) Allopurinol, a compound used to treat gout, is...
Explain how 13C NMR spectroscopy could be used to distinguish the ortho-, meta-, and para-dibromobenzene isomers one from another.
Write the structure of the product formed when each of the following compounds reacts with one molar equivalent of HCl. (a) (b) HCI(1 equiv.) CH3 HCl (1 equiv)
Which of the hydrogen atoms shown below is more acidic? Explain your answer. A
Although none of the [10]annulenes given in Section 14.7B is aromatic, the following 10 p-electron system is aromatic: What factor makes this possible?
Cycloheptatrienone (I) is very stable. Cyclopentadienone (II) by contrast is quite unstable and rapidly undergoes a Diels-Alder reaction with itself. (a) Propose an explanation for the different...
If benzene were 1,3,5-cyclohexatriene, the carbon-carbon bonds would be alternately long and short as indicated in the following structures. However, to consider the structures here as resonance...
For each of the pairs below, predict specific aspects in their 1H NMR spectra that would allow you to distinguish one compound from the other. (a) (b) (c) Br Br
Assign structures to each of the compounds A, B, and C whose 1H NMR spectra are shown in Fig. 14.27.
Apply the polygon-and-circle method to cyclopentadienyl cation and explain whether it would be aromatic or not. Cyclopentadienyl cation
Show how loss of a proton can be represented using each of the three resonance structures for the arenium ion and show how each representation leads to the formation of a benzene ring with three...
Chloroethene adds hydrogen chloride more slowly than ethene, and the product is 1,1-dichloroethane. How can you explain this using resonance and inductive effects? HCI CI CI
Write resonance structures for the arenium ions formed when ethylbenzene reacts with a Br+ ion (as formed from Br2/FeBr3) to produce the following ortho and para products. Br FeBr Br
Primary halides of the type ROCH2X apparently undergo SN1-type reactions, whereas most primary halides do not. Can you propose a resonance explanation for the ability of halides of the type ROCH2X to...
Given that the pKa of H2SO4 is -9 and that of HNO3 is -1.4, explain why nitration occurs more rapidly in a mixture of concentrated nitric and sulfuric acids than in concentrated nitric acid alone.
Both of the following syntheses will fail. Explain what is wrong with each one. (a) (b) NO2 (1) HNO/H SO (2) CH3COC/AIC (1) NBS, light (2) NaOEt, EtOH, heat (3) Br2, FeBr3
Predict the major products of the following reactions: (a) (c) (e) Product of (c) + H2O Product of (c) + H2 (1 molar equivalent) (g) Product of (f) HCI Styrene EtONa HA, heat OH peroxides HA heat Pt...
2,6-Dichlorophenol has been isolated from the females of two species of ticks (Amblyomma americanum and A. maculatum), where it apparently serves as a sex attractant. Each female tick yields about 5...
Give structures (including stereochemistry where appropriate) for compounds A-G: (a) (b) (c) (d) 2 NaNH2 Benzene+ o c heat (1) Li, EtNH2 E (C9H10 (2) NHCI (Section 7.15B)) Br2 D F+ enantiomer (major...
A C-D bond is harder to break than a C-H bond, and, consequently, reactions in which C-D bonds are broken proceed more slowly than reactions in which C-H bonds are broken. What mechanistic...
Furan undergoes electrophilic aromatic substitution. Use resonance structures for possible arenium ion intermediates to predict whether furan is likely to undergo bromination more rapidly at C2 or at...
Acetanilide was subjected to the following sequence of reactions: (1) concd H2SO4; (2) HNO3, heat; (3) H2O, H2SO4, heat, then HO-. The 13C NMR spectrum of the final product gives six signals. Write...
Explain how the percentages just given show that the methyl group exerts an ortho-para directive effect by considering the percentages that would be obtained if the methyl group had no effect on the...
Use resonance theory to explain why the hydroxyl group of phenol is an activating group and an ortho-para director. Illustrate your explanation by showing the arenium ions formed when phenol reacts...
When compound C, which is often used to model a more frequently occurring unit in lignins, was ozonized, product D was obtained. In a variety of ways it has been established that the stereochemistry...
What product would be obtained if A were treated with lithium aluminum hydride without first converting it to a cyclic acetal?
Give the structure of the product that would result from a Baeyer-Villiger oxidation of cyclopentanone.
Give a structural formula and another acceptable name for each of the following compounds: (a) Formaldehyde (b) Acetaldehyde (c) Phenylacetaldehyde (d) Acetone (e) Ethyl methyl ketone (f)...
Give structural formulas for the products formed (if any) from the reaction of acetone with each reagent?
Show how you would synthesize propanal from each of the following: (a) 1-propanol and (b) propanoic acid (CH3CH2CO2H).
(a) What would be the frequencies of the two absorption bands expected to be most prominent in the infrared spectrum of 4-hydroxycycloheptanone (C)? (b) In reality, the lower frequency band of these...
When (semicarbazide) reacts with a ketone (or an aldehyde) to form a derivative known as a semicarbazone, only one nitrogen atom of semicarbazide acts as a nucleophile and attacks the carbonyl carbon...
Dissolving formaldehyde in water leads to a solution containing primarily the gem-diol CH2(OH)2. Show the steps in its formation from formaldehyde.
Shown below is the structural formula for sucrose (table sugar). Sucrose has two acetal groupings. Identify these. OH O HO HO HO OH HO OH OH
(a) Provide the reagents required to accomplish the following transformation. (b) What product would you likely obtain if you attempted to synthesize the nitrile above by the following method? CO,H...
Give an IUPAC systematic or common name for each of the following compounds: (a) (b) (c) (d) (e) (f) (g) (h) CH3CN Cl NH2
Write structural formulas for the major organic products from each of the following reactions. (a) (b) (c) (d) (e) (f) (g) (h) O (excess), H SO (cat.) OH 0 H2O, H,so, (cat.) (1) Mg (2) CO2 (3) H2O Br...
Write structural formulas for the major organic products from each of the following reactions. (a) (b) (c) (d) (e) CI CH CH.SH NH2 (excess Cl OH H SO, (cat.) HO AlCl3
Provide a detailed mechanism for each of the following reactions. (a) (b) (c) H,so, (cat.) OCH3 + CH OH (excess) 0 EtNH2 (excess) Cl NH H,O, H,SO, (cat.) OH
The IR and 1H NMR spectra of phenacetin (C10H13NO2) are given in Fig. 17.7. Phenacetin is an analgesic and antipyretic compound and was the P of A-P-C tablets (aspirin-phenacetin-caffeine). (Because...
Given here are the 1H NMR spectra and carbonyl IR absorption peaks of five acyl compounds. Propose a structure for each. (a) (b) (c) (d) (e) OgH 1404 H NMR Spectrum Triplet 1.2(6H) Singlet 2.5(4H)...
(a) Which of the carboxylic acids in Practice Problem 17.6 could be prepared by a nitrile synthesis as well? In problem 17.6 (b) Which synthesis, Grignard or nitrile, would you choose to prepare OH ...
Provide a structural formula for the product from each of the following reactions. (a) (b) (c) (d) (e) (f) (1) LDA (2) CH,CH Br. CH,COH NaH Cl Br2 (excess), NaOH (1) LDA (3) H20 ), NaoH
The following reaction illustrates the Robinson annulation reaction (Section 19.7A). Provide a mechanism. base
Predict the products from each of the following aldol reactions. (a) (b) (c) (d) (e) H NaOH H20 H H NaOH H2O o'H H HOEN NaOH H2O H NaOH H2O
Show how you might prepare benzylamine from each of the following compounds: (a) (b) (c) Benzyl bromide (two ways) (d) Benzyl tosylate (e) Benzaldehyde (f) Phenylnitromethane (g) NH2 Benzylamine CN...
(a) Write resonance structures for the phthalimide anion that account for the acidity of phthalimide. (b) Would you expect phthalimide to be more or less acidic than benzamide? Why? (c) In step 3 of...
Review the chemistry of amines given in earlier sections and provide a specific example for each of the previously illustrated reactions.
Show how you might prepare each of the following amines through reductive amination: (a) (b) (c) NH2 CH3 CH3
When 2-bromo-1, 3-dimethylbenzene is treated with sodium amide in liquid ammonia, no substitution takes place. This result can be interpreted as providing evidence for the elimination-addition...
Provide a mechanism for the following reaction OH H2SO4 H20
1-Fluoro-2, 4-dinitrobenzene is highly reactive toward nucleophilic substitution through an SNAr mechanism. (In Section 24.5B we shall see how this reagent is used in the Sanger method for...
A, B, and C are three aldohexoses. Compounds A and B yield the same optically active alditol when they are reduced with hydrogen and a catalyst; A and B yield different phenylosazones when treated...
(a) Using the first codon given for each amino acid in Table 25.2, write the base sequence of mRNA that would translate the synthesis of the following pentapeptide: Arg Ile Cys Tyr Val (b) What...
Mutations can also be caused chemically, and nitrous acid is one of the most potent chemical mutagens. One explanation that has been suggested for the mutagenic effect of nitrous acid is the...
Draw the products of each of the following reactions indicated by the curved-arrow notation. (a) (b) CH CH NH2
Indicate whether each of the following statements is true or false. If false, explain why. (a) In every case, pair of enantiomers have a mirror- image relationship. (b) If a compound has an...
Draw a structure for each of the following compounds in its more stable chair conformation. Explain your choice. (a) (b) CH3 CH3 CH (CH),C CHA CH, ," CH3 CH3
Draw the structure of each of the following compounds. (a) Isobutyl alcohol (b) 3-methyl-2-pentanol (c) 2-cyclohexenol
Draw the structure of each of the following compounds. (a) Dicyclohexyl ether (b) Tert-butyl isopropyl sulfide (c) Phenyl vinyl ether (d) 5-(ethylthio)-2-methylheptane
(a) Show that the dipole moment of l,4-dioxane (Sec. 8.1C) should be zero if the molecule exists solely in a chair conformation, (b) Account for the fact that the dipole moment of 1,4- dioxane,...
What is the expected substitution product (including its stereochemical configuration) in the SN2 reaction of potassium iodide in acetone solvent with the following compound? (D = 2H = deuterium, an...
Predict the products expected in each of the following situations, and show the mechanism of any reaction that takes place using the curved-arrow notation. (a) 2-bromobutaneintert-butyl alcohol...
Choose the alkyl halide(s) frorn the following list of C6H13Br isomers that meet each criterion below. (1) l-bromohexane (2) 3 -bromo-3 -methylpentane (3 ) I -bromo-2,2-dimethylbutane (4) 3 -bromo-2-...
Give the curved-arrow mechanism for the reaction in Problem 10.la. In each step, identify all Bronsted acids and bases, all electrophiles and nucleophiles, and all leaving groups.
(a) Give a curved-arrow mechanism for the reaction in Eq. 10.6. (b) After reading Study Guide Link 10.2, explain why the rearrangement in Eq. 10.7 is favorable even though both of the carbocation...
Show two different Friedel-Crafts acylation reactions that can be used to prepare the following compound. CH3 CH CH3
Propose a curved-arrow mechanism for the reaction given in Fig. P16.64. Fig. P16.64 (CH)C
Two general mechanisms (or various versions of them) for alkene metathesis were originally considered. In the first (pair wise) mechanism, shown in Fig. P18.81, the catalyst brings about cyclobutane...
How many CO ligands would be accommodated by Fe(O) if we assume that the resulting complex follows the 18-electron rule?
Propose syntheses of each of the following acetals from carbonyl compounds and alcohols.
Identify the following compounds. C5H10O NMR: 9.8 (1H, s), 1.1 (9H, s)
Starting with any organic compound you wish, outline synthetic procedures for preparing each of the following isotopically labeled materials using the indicated source of the isotope. Although...
Show why HBr is a stronger acid in acetic acid solvent than it is in water.
How would you synthesize each of the following compounds from an acid chloride? (a) (b) ,-- NO, (CH),C-o-C-CH, C-o-c C CH2 C-O-C(CH)
Propose a synthesis for each of the following compounds from butyric acid and any other reagents. (a) 2-methyl-2-pentanol (b) CH3CH2CH2CH2CH2CH2NH2 (c) CH3CH2CH2CH2NH2
Propose a structure for a compound A that has an infrared absorption at 1820 cm-1 and a single proton NMR absorption at 1.5. Compound A reacts with water to give dimethylmalonic acid and with...
The reactions of ester enolate ions are not restricted to simple alkylations. With this in mind, suggest the structure of the product formed when the enolate ion formed by the reaction of fm-butyl...
Each of the following compounds is unstable and either exists as an isomer or spontaneously decomposes to other compounds. In each case, give the more stable isomer or decomposition product and...
Outline a second synthesis of N-ethyl-N-methylaniline (the target molecule in Study Prob-lem 23.3) by reductive amination.
Provide curved-arrow mechanisms for each of the reactions given in Fig. P25.41. Give the structure for the intermediates A and B in parts (d) (a) (b) + DSo, (dilute) + HCI
Give the major product expected when (a) Leucine is treated with p-toluenesulfonyl chloride (tosyl chloride). (b) Alanine is heated in methanol solvent with HCI catalyst.
What average yield per amino acid would be required to synthesize a protein containing 100 amino acids in 507% overall yield?
In paper electrophoresis, amino acids and peptides can be separated by their differential migration in an electric field. To the center of a strip of paper is applied a mixture of the following three...
Draw complete Lewis structures, including lone pairs, for the following compounds. (a) (b) (c) (d) (e) (f) (g) (h) pyridine pyrrolidine furan y-aminobutyric acid a neurotransmitter) CHO SO H
All of the following compounds can react as acids. Without using a table of acidities, rank them in order of increasing acidity. Explain your ranking. (a) CH3CH2SO3H (b) CH3CH2OH (c) CH3CH2COOH (d)...
Draw a line-angle formula for each compound in Problem 1-26. In problem (a) CH3COCH2CHCHCOOH (b) NCCH2COCH2CHO (c) CH2CHCH(OH)CH2CO2H (d) CH2CHC(CH3)CHCOOCH3
Draw Lewis structures for (a) Two compounds of formula C4H10 (b) Two compounds of formula C2H6O (c) Two compounds of formula C2H7N (d) Three compounds of formula C2H7NO (e) Three compounds of formula...
Give the molecular formula of each compound shown in Problem 1-31. In problem (a) (b) (c) (d) (e) (f) (g) (h) pyridine pyrrolidine furan y-aminobutyric acid a neurotransmitter) CHO SO H
Determine whether the following pairs of structures are actually different compounds or simply resonance forms of the same compounds. (a) (b) (c) (d) (e) (f) (g) (i) (j) and O- and and O- CH C H and...
In the following sets of resonance forms, label the major and minor contributors and state which structures would be of equal energy. Add any missing resonance forms. (a) (b) (c) (d) (e) CH,_...
Label the reactants in these acid-base reactions as Lewis acids (electrophiles) or Lewis bases (nucleophiles). Use curved arrows to show the movement of electron pairs in the reactions. (a) (b) (c)...
In each reaction, label the reactants as Lewis acids (electrophiles) or Lewis bases (nucleophiles). Use curved arrows to show the movement of electron pairs in the reactions. Draw in any nonbonding...
Use your results from Problem 3-25 to complete the following table. Each entry shows the positions of two groups arranged as shown. For example, two groups that are trans on adjacent carbons...
Label each hydrogen atom in the following compounds as primary (1°), secondary (2°), or tertiary (3°). (a) CH3 CH2 CH (CH3)2 (b) (CH3)3 CCH2CH3 (c) (CH3)2 CHCH (CH3) CH2 CH3 (d) (e) (f) ...
Determine whether the following objects are chiral or achiral. T 0/
Which of the following compounds are chiral? Draw each compound in its most symmetric conformation, star (*) any asymmetric carbon atoms, and draw any mirror planes. Label any meso compounds. You may...
For each pair of compounds, state which compound is the better SN2 substrate. (a) 2-methyl-1-iodopropane or tert-butyl iodide (b) cyclohexyl bromide or 1-bromo-1-methylcyclohexane (c) 2-bromobutane...
Each of the two carbocations in Solved Problem 6-2 can also react with ethanol to give a substitution product. Give the structures of the two substitution products formed in this reaction.
Under appropriate conditions, (S)-1-bromo-1-fluoroethane reacts with sodium methoxide to give pure (S)-1-fluoro-1-methoxyethane. (a) Why is bromide rather than fluoride replaced? (b) Draw perspective...