|Problem Set #10||Answers||January 16, 1998|
1. Propose a mechanism for the following reaction -
2. Show how you would convert (R)-2-butanol to (S)-2-butanethiol?
The conversion involves a change in configuration at C-2 of the butanol. In other words a bimolecular nucleophilic displacement (SN2) is needed.
SH- would be an effective nucleophile. This can be prepared by bubbling H2S into sodium hydroxide solution in water/ethanol.
BUT one cannot do a direct displacement of an OH group of an alcohol. This means that we must make the alcohol into a better leaving group. To do this we could react the 2-butanol with p-toluenesulphonyl chloride in pyridine as a solvent, isolate the tosylate ester, and then treat with SH- in water ethanol..........
3. Give the structural formula of an alkene and show the reagents needed to make the following alcohols.
4. Triethanolamine (TEA) is used in industry to remove acid components from gas streams. It also finds extensive use as a buffer in biological systems. "TEA" is made from ammonia and ethylene oxide as shown below. Show how this synthesis occurs and propose a mechanism for one of the steps.
5. Show you would effect the following reaction.
6. Try question 12.43 in Ege.
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