Organic Chemistry 6th Edition solutions

Organic Chemistry 6
Each compound gives only one signal in its 1 H-NMR spectrum. Propose a structural formula for each compound. (a) C3H6O (b) C5H10 (c) C5H12 (d) C4H6Cl4

Organic Chemistry 6
The line of integration of the two signals in the 1 H-NMR spectrum of a ketone with the molecular formula C7H14O rises 62 and 10 chart divisions, respectively. Calculate the number of hydrogens giving rise to each signal, and propose a structural formula for this ketone.

Organic Chemistry 6
Following are two constitutional isomers with the molecular formula C4H8O2. (1) O CH3CH2OCCH3 (2) O CH3CH2COCH3 (a) Predict the number of signals in the 1 H-NMR spectrum of each isomer. (b) Predict the ratio of areas of the signals in each spectrum. (c) Show how you can distinguish between these isom

Organic Chemistry 6
Following are pairs of constitutional isomers. Predict the number of signals in the 1 H-NMR spectrum of each isomer and the splitting pattern of each signal. CH3OCH2CCH3 and CH3CH2COCH3 O O CH3CCH3 and ClCH2CH2CH2Cl Cl Cl

Organic Chemistry 6
Following is a 1 H-NMR spectrum of 2-butanol. Explain why the CH2 protons appear as a complex multiplet rather than as a simple quintet. 98 654 7 0 a a b b e e c d c 321 ppm Chemical Shift ( ) expansion Solvent OH d c

Organic Chemistry 6
Explain how to distinguish between the members of each pair of constitutional isomers based on the number of signals in the proton-decoupled 13C-NMR spectrum of each member. (a) and (b) C C and CH2CH2CH3 H H3C H C C CH2CH3 H CH3CH2 H CH2 CH3

Organic Chemistry 6
Calculate the index of hydrogen defi ciency of these compounds. (a) Aspirin, C9H8O4 (b) Ascorbic acid (vitamin C), C6H8O6 (c) Pyridine, C5H5N (d) Urea, CH4N2O (e) Cholesterol, C27H46O (f) Dopamine, C8H11NO2

Organic Chemistry 6
Complete the following table. Which nucleus requires the least energy to fl ip its spin at this applied fi eld? Which nucleus requires the most energy? Applied Field Radio Frequency Energy Nucleus (tesla, T) (MHz) ( J/mol) 1 H 7.05 300 ______ 13C 7.05 75.5 ______ 19F 7.05 282

Organic Chemistry 6
The natural abundance of 13C is only 1.1%. Furthermore, its sensitivity in NMR spectroscopy (a measure of the energy difference between a spin aligned with or against an applied magnetic fi eld) is only 1.6% that of 1 H. What are the relative signal intensities expected for the 1 H-NMR and 13C- NMR s

Organic Chemistry 6
Following are structural formulas for three constitutional isomers with the molecular formula C7H16O and three sets of 13C-NMR spectral data. Assign each constitutional isomer its correct spectral data. CH3CCH2CH2CH2CH3 (b) (a) CH3CH2CH2CH2CH2CH2CH2OH CH3 OH CH3CH2CCH2CH3 (c) CH2CH3 OH Problems Spect

Organic Chemistry 6
Following are structural formulas for the cis isomers of 1,2-, 1,3-, and 1,4-dimethylcyclohexane and three sets of 13C-NMR spectral data. Assign each constitutional isomer its correct spectral data. CH3 CH3 (a) (b) (c) CH3 CH3CH3 CH3 Spectrum 1 Spectrum 2 Spectrum 3 31.35 34.20 44.60 30.67 31.30 35.1

Organic Chemistry 6
Following are structural formulas, dipole moments, and 1 H-NMR chemical shifts for acetonitrile, fl uoromethane, and chloromethane. CH3C#N CH3F CH3Cl Acetonitrile Fluoromethane Chloromethane 3.92 D 1.85 D 1.87 D d 1.97 d 4.26 d 3.05 (a) How do you account for the fact that the dipole moments of fl uo

Organic Chemistry 6
Following are three compounds with the molecular formula C4H8O2, and three 1 H-NMR spectra. Assign each compound its correct spectrum and assign all signals to their corresponding hydrogens. CH3COCH2CH3 O (1) HCOCH2CH2CH3 O (2) CH3OCCH2CH3 O (3) 10 9 8 7 6 5 4 3 2 1 0 ppm Chemical Shift ( ) Problems

Organic Chemistry 6
Following are 1 H-NMR spectra for compounds D, E, and F, each with molecular formula C6H12. Each readily decolorizes a solution of Br2 in CCl4. Propose structural formulas for compounds D, E, and F, and account for the observed patterns of signal splitting. 10 9 8 7 6 5 4 3 2 1 0 ppm Chemical Shift (

Organic Chemistry 6
Following are 1 H-NMR spectra for compounds G, H, and I, each with the molecular formula C5H12O. Each is a liquid at room temperature, is slightly soluble in water, and reacts with sodium metal with the evolution of a gas. (a) Propose structural formulas of compounds G, H, and I. (b) Explain why ther

Organic Chemistry 6
Propose a structural formula for compound J, molecular formula C3H6O, consistent with the following 1 H-NMR spectrum. 10 9 8 7 6 5 4 3 2 1 0 ppm Chemical Shift ( ) expansion C3H6O Compound J 1H 3H 1H 1H 3 2 1H 1H 1H

Organic Chemistry 6
Compound K, molecular formula C6H14O, readily undergoes acid-catalyzed dehydration when warmed with phosphoric acid to give compound L, molecular formula C6H12, as the major organic product. The 1 H-NMR spectrum of compound K shows signals at d 0.90 (t, 6H), 1.12 (s, 3H), 1.38 (s, 1H), and 1.48 (q, 4

Organic Chemistry 6
Compound M, molecular formula C5H10O, readily decolorizes Br2 in CCl4 and is converted by H2/Ni into compound N, molecular formula C5H12O. Following is the 1 H-NMR spectrum of compound M. The 13C-NMR spectrum of compound M shows signals at d 146.12, 110.75, 71.05, and 29.38. Deduce the structural for

Organic Chemistry 6
Following is the 1 H-NMR spectrum of compound O, molecular formula C7H12. Compound O reacts with bromine in carbon tetrachloride to give a compound with the molecular formula C7H12Br2. The 13C-NMR spectrum of compound O shows signals at d 150.12, 106.43, 35.44, 28.36, and 26.36. Deduce the structural

Organic Chemistry 6
Treatment of compound P with BH3 followed by H2O2/NaOH gives compound Q. Following are 1 H- NMR spectra for compounds P and Q along with 13C-NMR spectral data. From this information, deduce structural formulas for compounds P and Q. C7H12 1. BH3 2. H2O2, NaOH C7H14O (P) (Q) 13C-NMR (P) (Q) 132.38 Pro

Organic Chemistry 6
The 1 H-NMR of compound R, C6H14O, consists of two signals: d 1.1 (doublet) and d 3.6 (septet) in the ratio 6 : 1. Propose a structural formula for compound R consistent with this information.

Organic Chemistry 6
Write structural formulas for the following compounds. (a) C2H4Br2: d 2.5 (d, 3H) and 5.9 (q, 1H) (b) C4H8Cl2: d 1.60 (d, 3H), 2.15 (m, 2H), 3.72 (t, 2H), and 4.27 (m, 1H) (c) C5H8Br4: d 3.6 (s, 8H) (d) C4H8O: d 1.0 (t, 3H), 2.1 (s, 3H), and 2.4 (quartet, 2H) (e) C4H8O2: d 1.2 (t, 3H), 2.1 (s, 3H), a

Organic Chemistry 6
The percent s-character of carbon participating in a C!H bond can be established by measuring the 13C!1 H coupling constant and using the relationship Percent s-character 5 0.2 J(13C!1 H) The 13C!1 H coupling constant observed for methane, for example, is 125 Hz, which gives 25% s-character, the valu

Organic Chemistry 6
Ascaridole is a natural product that has been used to treat intestinal worms. Explain why the two methyls on the isopropyl group in ascaridole appear in its 1 H-NMR spectrum as four lines of equal intensity, with two sets of two each separated by 7 Hz. O O Ascaridole

Organic Chemistry 6
The 13C-NMR spectrum of 3-methyl-2-butanol shows signals at d 17.88 (CH3), 18.16 (CH3), 20.01 (CH3), 35.04 (carbon-3), and 72.75 (carbon-2). Account for the fact that each methyl group in this molecule gives a different signal.

Organic Chemistry 6
Sketch the NMR spectrum you would expect from a partial molecule with the following parameters. C R C Ha R C R Hc Hc Hb Ha 5 1.0 ppm Hb 5 3.0 ppm Hc 5 6.0 ppm J ab 5 5.0 Hz Jbc 5 8.0 Hz J ac 5 1.0 Hz R