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2003
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June
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In the Laboratory
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Bromination and Debromination of Cholesterol: An Inquiry-Based Lab Involving Structure Elucidation, Reaction Mechanism, and 1H NMR
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Andrew Grant
Department of Chemistry, Mount Allison University, Sackville, NB, Canada, E4L 1G8
Devin Latimer
Department of Chemistry, University of Winnipeg, Winnipeg, MB, Canada, R3B 2E9
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June 2003
Vol. 80 No. 6
p. 670
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| Abstract |
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A classic laboratory experiment involving the bromination of cholesterol and subsequent zinc-mediated debromination back to cholesterol has been reworked for use in an upper-level organic lab. The emphasis has been changed from the purification of cholesterol to a structure determination, conformation, stereochemistry, and mechanism investigation. A series of instructions and questions designed to help the students deduce the structure and three-dimensional shape of dibromocholesterol from approximate 1H NMR data has been developed. Dihedral angles from the three-dimensional perspective drawings and the approximate coupling constants gleaned from 1H NMR data provide the basis for a structural assignment of the dibromocholesterol and allow for a mechanism of bromination to be proposed.
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| Supplement |
Instructions for the students, suggested answers to questions, a note for the instructor, and CAS registry numbers for required chemicals are available.
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 Contents |
Folder JCE2003p0670W containing JCE2003p0670W.wpd (WordPerfect), CHOLEST.CDX, CHOLEST2.CDX, and CHOLEST3.CDX
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| More Information |
Citation |
Grant, Andrew S.; Latimer, Devin. J. Chem. Educ. 2003 80 670.
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Keywords |
Inquiry-Based / Discovery Method; Mechanisms; NMR Spectrometry; Organic Chemistry; Stereochemistry; Natural Products; Organic Synthesis
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History |
Created:
Last Updated: |
May 5, 2003
February 28, 2005
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Link to Featured Molecules added (April 2004).
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| Home > JCE Print > Journal of Chemical Education > Issues >
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June
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670
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