Outline a general method for the synthesis of each of the following polymers by radical polymerization. Show the monomers that you would use. (a) (b) OCHs OCH3 OCH3 CI CI CI CI CI CI
Alkenes such as ethene, vinyl chloride, and acrylonitrile do not undergo cationic polymerization very readily. On the other hand, isobutylene undergoes cationic polymerization rapidly. Provide an...
Suggest a method for separating and isolating the CH3Cl, CH2Cl2, CHCl3, and CCl4 that may be formed as a mixture when methane is chlorinated. (You may want to consult a handbook.) What analytical...
(a) What monobromo allylic substitution products would result from reaction of each of the following compounds with NBS in the presence of peroxides and/or light? (b) In the case of isomeric products...
Which of the following compounds can be prepared by radical halogenation with little complication by formation of isomeric by-products? CI CI
List in order of decreasing stability all of the radicals that can be obtained by abstraction of a hydrogen atom from 2-methylbutane.
Find examples of C-H bond dissociation energies in Table 10.1 that are as closely related as possible to the bonds to Ha, Hb, and Hc in the molecule at right. Use these values to answer the questions...
Starting with the compound or compounds indicated in each part and using any other needed reagents, outline syntheses of each of the following compounds. (You need not repeat steps carried out in...
How would the molecular ion peaks in the respective mass spectra of CH3Cl, CH2 Cl2, CHCl3, and CCl4 differ on the basis of the number of chlorines? (Remember that chlorine has isotopes 35Cl and 37Cl...
The following reaction is the first step in the industrial synthesis of acetone and phenol (C6H5OH). AIBN (2,29-azobisisobutyronitrile) initiates radical reactions by breaking down upon heating to...
Hydrogen peroxide and ferrous sulfate react to produce hydroxyl radical (HO), as reported in 1894 by English chemist H. J. H. Fenton. When tert-butyl alcohol is treated with HO generated this way, it...
Write a mechanism that accounts for the following reaction. The hydrogen atom bonded to tin in tributyltin hydride is readily transferred in radical mechanisms. Br PhCO22, BuSnH (Major)
(a) Outline two methods for preparing isopropyl methyl ether by a Williamson ether synthesis. (b) One method gives a much better yield of the ether than the other. Explain which is the better method...
Molecular orbital calculations can be used to model the location of electron density from unpaired electrons in a radical. Open the molecular models on the book's website for the methyl, ethyl, and...
When an ether is treated with cold concentrated HI, cleavage occurs as follows: When mixed ethers are used, the alcohol and alkyl iodide that form depend on the nature of the alkyl groups. Use...
Outline a mechanism similar to the one just given that shows how the enantiomeric form of trans-1,2-cyclopentanediol is produced.
Write structures for (a) 15-crown-5 and (b) 12-crown-4.
Provide the alkene needed to synthesize each of the following by hydroboration oxidation. (a) (b) (c) (d)
Starting with each of the following, outline a practical synthesis of 1-butanol: (a) 1-Butene (b) 1-Chlorobutane (c) 2-Chlorobutane (d) 1-Butyne
Propose a reasonable mechanism for the following reaction. cat. H2SO4 OH- C3
Propose a reasonable mechanism for the following reaction. OH
Predict the products from each of the following reactions. (a) (b) (c) (d) (e) (f) (g) (h) (i) (j) Hl (excess) Hi H,so,,H20 O MeONa O MeOH, cat. H2SO (1) EtSNa (2) H2o HCl (1 equiv.) MeONa (1)EtON...
Write equations for the acid-base reactions that would occur (if any) if ethanol were added to solutions of each of the following compounds. In each reaction, label the stronger acid, the stronger...
Compounds of the type Called a-haloalcohols, are unstable and cannot be isolated. Propose a mechanistic explanation for why this is so. HO
When the 3-bromo-2-butanol with the stereochemical structure A is treated with concentrated HBr, it yields meso-2,3-dibromobutane; a similar reaction of the 3-bromo-2-butanol B yields...
(a) What factor explains the observation that tertiary alcohols react with HX faster than secondary alcohols? (b) What factor explains the observation that methanol reacts with HX faster than a...
What products would you expect from the reaction of propyllithium (CH3CH2CH2Li) with each of the following reagents? (a) (b) (c) (d) Ethanol (e) H, then H3O , then NH,CI, H20 1-Pentyne, then , then...
Studies suggest that attack by a Grignard reagent at a carbonyl group is facilitated by involvement of a second molecule of the Grignard reagent that participates in an overall cyclic ternary...
What organic products A-H would you expect from each of the following reactions? MeLi (1) NaH HELO A (2) NH4Cl,H20 OMS Ni,B (P-2), H2 NaBH MeOH (1) LAH (2) aq. H.SO4 MsCI PyT
An unknown X shows a broad absorption band in the infrared at 3200-3550 cm-1 but none in the 1620-1780 cm-1 region. It contains only C, H, and O. A 116-mg sample was treated with an excess of...
Provide the reagents necessary to achieve the following transformations. (a) (b) (D = deuterium)
If (2Z,4Z)-hexa-2,4-diene were able to undergo a Diels-Alder reaction with methyl propenoate, what would be the products? (Hint: There are four products comprised of two pairs of enantiomers. One...
Which diene and dienophile would you employ to synthesize the following compounds? (a) (b) CO2Me CO2Me
Show how each of the following transformations could be accomplished: (a) (b) (c) (d) (e)
Predict the products of the following acid-base reactions. Using pKa values, indicate which side of each equilibrium reaction is favored, and label the species representing the stronger acid and...
1,3-Butadiene and the dienophile shown below were used by A. Eschenmoser in his synthesis of vitamin B12 with R. B. Woodward. Draw the structure of the enantiomeric Diels-Alder adducts that would...
What products would you expect from the reaction of 1 mol of 1,3-butadiene and each of the following reagents? (If no reaction would occur, you should indicate that as well.) (a) 1 mol of Cl2 (b) 2...
When 2-methyl-1,3-butadiene (isoprene) undergoes a 1,4-addition of hydrogen chloride, the major product that is formed is 1-chloro-3-methyl-2-butene. Little or no 1-chloro-2-methyl-2-butene is...
What products would you expect from the following reactions? (a) (b) (c) (d) (e) OMe OMe
(a) The hydrogen atoms attached to C3 of 1,4-pentadiene are unusually susceptible to abstraction by radicals. How can you account for this? (b) Can you provide an explanation for the fact that the...
Provide a mechanism that explains formation of the following products. Include all intermediates, formal charges, and arrows showing electron flow. 0 N-Br (NBS) 0 hv 11
Provide a mechanism that explains formation of the following products. CI HCI (concdCI+
Provide a mechanism that explains formation of the following products. OMe MeOH +CI OMet
(a) Norbornadiene for the aldrin synthesis (Problem 13.46) can be prepared from cyclopentadiene and acetylene. Show the reaction involved. (b) It can also be prepared by allowing cyclopentadiene to...
The following enol (an alkene-alcohol) and keto (a ketone) forms of C2H4O differ in the positions for their electrons, but they are not resonance structures. Explain why they are not. :O C2H4O Enol...
Which diene and dienophile would you employ in a synthesis of each of the following? (a) (b) (c) (d) (e) (f) (g) OMe OMe OMe CN CO2Me
Write structural formulas for each of the following: (a) 3-Nitrobenzoic acid (b) p-Bromotoluene (c) o-Dibromobenzene (d) m-Dinitrobenzene (e) 3,5-Dinitrophenol (f) p-Nitrobenzoic acid (g)...
Write structural formulas and give acceptable names for all representatives of the following: (a) Tribromobenzenes (b) Dichlorophenols (c) Nitroanilines (d) Methylbenzenesulfonic acids (e) Isomers of...
Use the polygon-and-circle method to draw an orbital diagram for each of the following compounds. (a) (b)
Explain the following: (a) Cyclononatetraenyl anion is planar (in spite of the angle strain involved) and appears to be aromatic. (b) Although [16]annulene is not aromatic, it adds two electrons...
Furan possesses less aromatic character than benzene as measured by their resonance energies (96 kJ mol-1 for furan; 151 kJ mol-1 for benzene). What reaction have we studied earlier that shows that...
Give a structure for compound F that is consistent with the 1H NMR spectrum in Fig. 14.28 and IR absorptions at 3020, 2965, 2940, 2870, 1517, 1463, and 818 cm-1.
Compound M has the molecular formula C9H12. The 1H NMR spectrum of M is given in Fig. 14.29 and the IR spectrum in Fig. 14.30. Propose a structure for M.
The IR and 1H NMR spectra for compound X (C8H10) are given in Fig. 14.33. Propose a structure for compound X.
(a) How many signals would you expect to find in the 1H NMR spectrum of caffeine? (b) What characteristic peaks would you expect to find in the IR spectrum of caffeine? CH3 CH3 Caffeine
Given the following information, predict the appearance of the 1H NMR spectrum arising from the vinyl hydrogen atoms of p-chlorostyrene. Deshielding by the induced magnetic field of the ring is...
The cyclopentadienyl cation is apparently antiaromatic. Explain what this means in terms of the p-electron energies of a cyclic and an open-chain compound.
What products would you obtain from acidic and basic hydrolysis of each of the following amides? (a) N, N-Diethylbenzamide (b) (c) NH2 HO (a dipeptide) CeHs
Write structures for the products of the following reactions: (a) C6H5CH2OH + C6H5N==C==O : (b) ClCOCl + excess CH3NH2 : (c) Glycine (H3+NCH2CO2-) + C6H5CH2OCOCI HO:- (d) Product of (c) + H2, Pd :...
Using decarboxylation reactions outline a synthesis of each of the following from appropriate starting materials: (a) 2-Hexanone (b) 2-Methylbutanoic acid (c) Cyclohexanone (d) Pentanoic acid
Amides are weaker bases than corresponding amines. For example, most water-insoluble amines (RNH2) will dissolve in dilute aqueous acids (aqueous HCl, H2SO4, etc.) by forming water-soluble...
What products would you expect to obtain when propanamide reacts with each of the following? (a) H3O+, H2O (b) HO-, H2O (c) P4O10 and heat
Diacyl peroxides decompose readily when heated. (a) What factor accounts for this instability? (b) The decomposition of a diacyl peroxide produces CO2. How is it formed? (c) Diacyl peroxides are...
An alternative synthesis of ibuprofen is given below. Supply the structural formulas for compounds A-D: Cl Ci ACl3 NaCN, -HI red P buprofen (racemic) HCI, Z D
As a method for the synthesis of cinnamaldehyde (3-phenyl-2-propenal), a chemist treated 3-phenyl-2-propen-1-ol with K2Cr2O7 in sulfuric acid. The product obtained from the reaction gave a signal at...
Starting with either cis-or trans-HO2C--CH==CH--CO2H (i.e., either maleic or fumaric acid) and using any other needed compounds, outline syntheses of each of the following: (a) (b) (c) CO2H CO2H
Cantharidin is a powerful vesicant that can be isolated from dried beetles (Cantharis vesicatoria, or "Spanish fly"). Outlined here is the stereospecific synthesis of cantharidin reported by Gilbert...
Shown below is a synthesis of the elm bark beetle pheromone, multistriatin (Problem 16.44). Give structures for compounds A, B, C, and D. TsC OH LiAIH, base Lewis acid C (C10H1BO) Multistriatin
(a) Write a mechanism for all steps of the Claisen condensation that take place when ethyl propanoate reacts with ethoxide ion. (b) What products form when the reaction mixture is acidified?
(a) Write resonance structures for the anion of acetonitrile that account for its being much more acidic than ethane. (b) Give a step-by-step mechanism for the condensation of benzaldehyde with...
Assuming that dehydration occurs, write the structures of the two other products that might have resulted from the aldol cyclization just given. (One of these products will have a five-membered ring...
When acrolein (propenal) reacts with hydrazine, the product is a dihydropyrazole: Suggest a mechanism that explains this reaction. H + H2N-NH2 Acrolein Hydrazine A dihydropyrazole
Write a stepwise mechanism for each of the following reactions. (a) (b) (c) (d) NaOH, H2C NaOD, D2o NaOH, H2O (1) LDA (2) CH
(a) Propose step-by-step mechanisms for both transformations of the Robinson annulations sequence just shown. (b) Would you expect 2-methylcyclohexane-1, 3-dione to be more or less acidic than...
(a) What product would you expect from a Dieckmann condensation of diethyl heptanedioate? (b) Can you account for the fact that diethyl pentanedioate (diethyl glutarate) does not undergo a Dieckmann...
In the presence of sodium ethoxide the following transformation occurs. Explain. (1) NaOEt (2) HCI OEt OEt
(a) Write a reaction involving a lithium enolate for introduction of the methyl group in the following compound (an intermediate in a synthesis by E. J. Corey of cafestol, an anti-inflammatory agent...
Provide a mechanism for the following reaction. NaOH H20
(+)-Fenchone is a terpenoid that can be isolated from fennel oil. (±)-Fenchone has been synthesized through the following route. Supply the missing intermediates and reagents. CO2Me CO2Me...
Allowing acetone to react with 2 molar equivalents of benzaldehyde in the presence of KOH in ethanol leads to the formation of compound X. The 13C NMR spectrum of X is given in Fig. 19.1. Propose a...
Show how each of the following transformations could be accomplished. You may use any other required reagents. (a) (b) (c) (d) (e) (f) (g) NO2 CN CH3CN CH3
What starting materials are needed to synthesize each of the following compounds using an aldol reaction? (a) (b) (c) (d) (e) (f) (g) (h) Ph Ph
(a) Provide a mechanism for the aldol addition of propanal shown here. (b) How can you account for the fact that the product of the aldol addition is 3-hydroxy- 2-methylpentanal and not...
In the preceding examples of diazonium reactions, we have illustrated syntheses beginning with the compounds (a)-(d) here. Show how you might prepare each of the following compounds from benzene: (a)...
(a) In Section 20.7D we showed a synthesis of m-fluorotoluene starting with m-toluidine. How would you prepare m-toluidine from toluene? (b) How would you prepare m-chlorotoluene? (c) m-Bromotoluene?...
Write mechanisms that account for the products of the following reactions: (a) (b) (c) EtO OEt OEt+ EtONa Eto OEt O C OMe OMe CH NHa OMe base CH H3 OEt EtONa (-EtoH) EtO OEt OEt Eto OEt
The mandibular glands of queen bees secrete a fluid that contains a remarkable compound known as "queen substance." When even an exceedingly small amount of the queen substance is transferred to...
Outline a synthesis of orange II from 2-naphthol and p-aminobenzenesulfonic acid.
Azo compounds can be reduced to amines by a variety of reagents including stannous chloride (SnCl2): Give a structure for phenacetin and for the intermediates A, B, and C. SnCl2 (1) HONO, H2O (2)...
Sulfonamides of primary amines are often used to synthesize pure secondary amines. Suggest how this synthesis is carried out.
Give common or systematic names for each of the following compounds: (a) (b) (c) (d) (e) (f) (g) (h) (i) (j) (k) CH3N+H3 CH3CO2 - (l) (m) (n) NH2 HIN NH2 CH3 NH2 OCH NIH N NH2 SO NH2 NH2 CH3
What products would you expect to be formed when each of the following amines reacts with aqueous sodium nitrite and hydrochloric acid? (a) Propylamine (b) Dipropylamine (c) N-Propylaniline (d) N,...
Using reactions that we have studied in this chapter, propose a mechanism that accounts for the following reaction: CN H2 Pd
Give structures for compounds R-W: CHal H.O) Ag20 H20 N-Methylpiperidine- R (CH16NI) 0-5 (C,HyNO) at CHal H2O
Para-nitrosation of N,N-dimethylaniline (C-nitrosation) is believed to take place through an electrophilic attack by N+O ions. (a) Show how N+O ions might be formed in an aqueous solution of NaNO 2...
Propose structures for compounds X, Y, and Z: The 1H NMR spectrum of X gives two signals, a multiplet at δ 7.3 (5H) and a singlet at δ 4.25 (2H); the 680-840-cm-1 region of...
Using a different method for each part, but taking care in each case to select a good method, show how each of the following transformations might be accomplished: (a) (b) (c) (d) (e) NH2 NH2 CH3O...
What products would be obtained from each of the following acid-base reactions? (a) Sodium ethoxide in ethanol + phenol (b) Phenol + aqueous sodium hydroxide (c) Sodium phenoxide + aqueous...
A synthesis of the b-receptor blocker called toliprolol begins with a reaction between 3-methylphenol and epichlorohydrin. The synthesis is outlined below. Give the structures of the intermediates...
Provide a mechanism for the following reaction. H2SO H2O