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2004
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March
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In the Laboratory
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Developing Investigation Skills in an Introductory Multistep Synthesis Using Fluorene Oxidation and Reduction
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Mark G. Stocksdale, Steven E. S. Fletcher, Ian Henry, and Paul J. Ogren
Department of Chemistry, Earlham College, Richmond, IN 47374
Michael A. G. Berg, Roy D. Pointer, and Barrett W. Benson
Department of Chemistry, Bloomsburg University, Bloomsburg, PA 17815
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March 2004
Vol. 81 No. 3
p. 388
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| Abstract |
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A two-step reaction sequence in the beginning organic laboratory provides a useful introduction to the importance of multistep synthesis. In addition to introducing several common synthetic methods and techniques, a two-step preparation can quickly establish the importance of testing alternative reactions in order to optimize intermediate yields. This article describes the preparation of 9-fluorenol in a sequence that first oxidizes fluorene to 9-fluorenone, followed by reduction of the ketone to 9-fluorenol. The entire experiment occurs over three lab periods. Air oxidation of fluorene under basic conditions is compared with an alternative oxidation using acidic chromate conditions. Students use semiquantitative TLC and product recoveries from column chromatography to determine which procedure provides the better yield of fluorenone. A final sodium borohydride reduction of the fluorenone then provides 9-fluorenol. All isolated products can be characterized using a variety of methods including melting points, IR, 1H, and 13C NMR. Students report crude and pure product yields as well as the overall yield of the two-step sequence. They are also asked to present supporting evidence for their findings as part of a formal report on this project.
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| Supplement |
Detailed laboratory instructions for the students, notes for the instructor, additional information on the TLC product analysis for the chromate oxidation method, and NMR and IR data are available.
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 Contents |
JCE2004p0388W.doc (Microsoft Word)
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| Download |
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| More Information |
Citation |
Stocksdale, Mark G.; Fletcher, Steven E. S.; Henry, Ian; Ogren, Paul J.; Berg, Michael A. G.; Pointer, Roy D.; Benson, Barrett W. J. Chem. Educ. 2004 81 388.
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Keywords |
Chromatography; IR Spectroscopy; Laboratory Instruction; NMR Spectrometry; Organic Synthesis
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History |
Created:
Last Updated: |
February 3, 2004
February 18, 2005
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| Home > JCE Print > Journal of Chemical Education > Issues >
2004
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March
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388
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