Ch11 - 242 S olutions C hapter 10 Alcohols Problem 10.56 Paroxetine(paxil is an antidepressant that is a member o f a family o f d rugs known as

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--- 242 Solutions Chapter 10: Alcohols . Problem 10.56 Paroxetine (paxil) is an antidepressant that is a member of a family of drugs known as Selective Serotonin Reu Inhibitors (SSRls). This family of drugs also includes fluoxetine (Prozac) and sertraline (Zoloft). SSRls work by inhibiting the reuptake of the neurotransmitter serotomn In the synapses of the central nervous system following releas'e of serotonin durin<> exc!tat!on of individual nerve cells. Between ~rings, the serotonin .is taken back up by ~ nerve cell in preparation for firing ag~n. InhIbItIOn of reuptake has the effect of IncreasIng the time serotomn molecules remaIn In the synapsesfollowin<> excitation,lea to a therapeutic effect. In one synthesis of paroxetine, the following reagents are used. Draw the structures of synthetic intermediates Aand B. 6 ·0"'''-0 N I A B The first reaction generates a primarily alkyl chloride (A) from the primary alcohol, which is displaced by the nucleophilic OH group in an SN2 reaction to give ether product B. . . . Probleml0.57Tartaric acid is an inexpensive and readily available chiralstarting material for the'synthesis of chiral molecules. ~ well-known prostaglandin synthe~is~ the (S,S)-tartaric aeid enantiomer was used to prepare the chiral diol in several steps. The ~hu'al dl~1 was Isolated as a synthetIC lI1termedlate and the follOWIng reagents are used. Draw the structures of synthetic . IntermedIates A and B.. ..' HOVOH ':;:;:1 H0J--\0H H,COt CI Nal ... B A HO OH -=:~"~ ... ~..... ~ /,0. Pyridine'" Acetone (S,s)-Tartaric acid /"-. H.JCY"n . oCH.J . ~~o' ~ "~ I . S~S . c!f '0. j \ . 0/ ~ . o X ° A B The first reaction OCqlfS on the two primary alcohol 'groups to give the corresponding double sulfonic ester (A); which are both displaced by the nucleophilic iodide anion in an SN2 reaction in the second step to give the diiodo product (B). ' Chapter 11: Ethers, Epoxides, and Sulfides Solutions 243 CHAPTER 11 Solutions to the Problems Eroblem 11.1 Write IUPAC and common names for these ethers. · OEt (c) (a) ex OEt 1_Ethoxy-2-methylpropane 1,2-Dimethoxyethane cis-1 ,2-Diethoxycyelohexane. (Ethyl isobutyl ether) (Ethylene glycol dimethyl ether) Emblem 11,2 Arrange these compounds in order of increasing boiling point. HO . ~OM /'~OH Boiling point increases with an increasing number of hydrogen bonding groups. In order of increasing boiling point, they are: o~ ./'- HO, /'- /' ~ 'OH ~ 125°C 198°C problem 11.3 Show how you might use the Williamson ether synthesis to prepare each ether: ~.O~ (a) V . There are two combinations of reagents that could produce the desired ether in high yield because both involve primary haloalkanes and are thus unlikely. to eliminate via an E2 pathway. ~o~.# + ~O-'K+ V + ~Br (b) ~O~ . Treatment of 1-bromobutane with sodium butoxide gives dibutyl ether. Problem llA Show how ethyl hexyl ether might be prepared by a Williamson ether synthesis. Using the Williamson ether synthesis, ethyl hexyl ether could be synthesized by either of the two following routes: CH 3 2 Br + CH3(CH2)4CH20-Na+ .
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This note was uploaded on 07/09/2011 for the course CHE 301 taught by Professor Diver during the Spring '08 term at SUNY Buffalo.

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Ch11 - 242 S olutions C hapter 10 Alcohols Problem 10.56 Paroxetine(paxil is an antidepressant that is a member o f a family o f d rugs known as

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