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Solutions to Problems Amines

Building Bridges to Knowledge

Perspective, Photo of an unknown fence

MichaelleCadet

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1. Suggests syntheses for each of the following from benzene

and any other necessary organic and/or inorganic materials.

(a)

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(b)

5

(c)

6

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(d)

8

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(e)

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(f)

2. Which of the following is more basic? Rationalize your

answer.

(a)

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(b)

(c)

(c) > (b) > (a) 3. Which of the following is the stronger acid, tetrahydropyrrole

or pyrrole? Give a rationale for your answer.

because the lone pair of electrons in pyrrole contributes to the aromatic character of the ring; therefore, the lone pair are not available to function as a Lewis base. On the other hand, the lone pair of electrons in tetrahydropyrrole ate available fo function as a Lewis base.

4. Write the series of elementary steps (the mechanism) to

rationalize the following conversion.

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(1)

(2)

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(3)

5. Phosphate esters, referred to as phospholipids, are

biologically important chemicals. Choline, constituent of phosphate esters, has a molecular formula

C5H14NO dissolves in water to form a solution with a pH that is considerably higher than 7. Choline can be synthesized from trimethylamine, water, and ethylene oxide. Suggest a structural formula for choline.

Write an equation showing the Arrhenius definition of choline as a base.

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An important derivative of choline is acetylcholine, a

neurotransmitter in the peripheral and central nervous systems, is an important biological molecule. Suggest a structure for acetylcholine.

6. The proton magnetic resonance and C-13 magnetic resonance spectra of a compound containing 78.5% carbon, 8.4% hydrogen, and 13.1% nitrogen are indicated below. Suggest a structural formula for the compound.

H1 NMR

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13C NMR

7. Suggest structural formulas for A, B, C, D, E, F, and G in the

following pathway:

A + heat → B (C9H15N) B + CH3I → C10H18NI + Ag2O → C (C10H19ON) C + heat → D (C10H17N) D + CH3I → C11H20NI + Ag2O → E (C11H21ON) E + heat → F (C8H10) F + Br2 → G (C8H10Br2)

NCH3

ONaBH4

H2OA

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G + alc KOH → H (C8H8)

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8. Vitamin B5,C9H17O5N, is a water soluble vitamin called

pantothenic acid. Vitamin B5 is needed to synthesize coenzyme Q and to metabolize proteins. Vitamin B5 reacts with sodium hydroxide, and then ethyl alcohol to produce C11H21O5N. C11H21O5N reacts with NaOH to give C6H11O4Na and sodium 3-aminopropionate. Acid hydrolysis of C6H11O4Na and sodium 3-aminopropionate produced C6H12O4 and 3-aminopropionic acid.

Following is a pathway for the formation of Vitamin B5 : (1)

(2)

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(3)

(4)

(5)

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9. An unknown compound exhibited the following H1 NMR, 13C

NMR, and partial mass spectra. In addition, the compound exhibited prominent infrared transmittance signals at 2222 cm-1 and 3333 cm-1. The molecular formula for the unknown compound is C3H4NClO.

H1 NMR

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13C NMR

Partial Mass Spectrum

The unknown dissolves in sodium hydroxide to form a substance that gives a negative test for chlorine. Suggest structural formulas for the unknown that exhibits the given spectra and the compound that is formed when the unknown is treated with NaOH.

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10. A popular anesthetic with the molecular formula C13H20O2N2

is insoluble in water and aqueous NaOH; however, the compound is soluble in dilute hydrochloric acid. When C13H20O2N2 is treated with sodium nitrite and hydrochloric acid under chilled conditions, C13H18O2N3Cl produced. The proton magnetic spectrum of the anesthetic is listed below. Boiling C13H20O2N2 in sodium hydroxide followed by acidification produces two separable compounds, C7H7O2N and C6H15ON. Spectra of these two compounds are indicated below.

H1 NMR of C13H20O2N2

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13C NMR of C13H20O2N2

H1 NMR of C6H15ON

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13C NMR of C6H15ON

H1 NMR C7H7O2N

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3C NMR of C7H7O2N

Suggest structures for C13H20O2N2, C13H18O2N3Cl, C7H7O2N and C6H15ON.

C13H20O2N2

C13H18O2N3Cl

C7H7O2N

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C6H15ON

11. Suggest a synthesis for the following compound from

benezene as the only organic starting material and any necessary inorganic material.

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12. Compound H is an anti-inflammatory agent. Suggest a synthesis for compound H from benzene as the only organic starting material and any other necessary inorganic reagents.

Compound H

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13. The following reaction is known as the Hoesch reaction.

Suggest mechanistic pathways, i.e., the series of elementary steps to account for the formation of this compound.

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(1)

(2)

Acid Hydrolysis (1)

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(2)

(3)

(4)

(5)

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(6)

14. Suggest a synthesis for 1,3-dihydoxybenzene (resorcinol or

m-dihydroxybenzene or m-hydroxphenol) from benzene as the only organic starting material and any other necessary inorganic reagents.

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15. The synthesis of compounds K, L, M and N can be

accomplished by the following sequence of reactions.

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The molecular formula of G and H is C7H7ONa

I

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H J

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H1 NMR compounds K and L

C13 NMR compounds K and L

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H1 NMR compounds M and N

C13 NMR compounds M and N