|
|
| Home > JCE Print > Journal of Chemical Education > Issues >
2006
>
September
> |
|
In the Laboratory
|
|
|
|
3,5-Diarylisoxazoles: Individualized Three-Step Synthesis and Isomer Determination Using 13C NMR or Mass Spectroscopy
|
Chad E. Stephens and Reem K. Arafa
Department of Chemistry, Georgia State University, Atlanta, GA 30303
|
|
September 2006
Vol. 83 No. 9
p. 1336
|
|
|
|
|
|
|
| Abstract |
|
As a multistep synthetic project for the second-semester organic laboratory, the three-step synthesis and definitive characterization of a 3,5-diarylisoxazole via the chalcone and the chalcone dibromide is described. As each student prepares a differently substituted chalcone, and thus isoxazole, the project is individualized with regard to compound purification, characterization, and literature searches. To determine which isoxazole isomer was obtained from the synthesis, students compare their experimental 13C NMR data for C4 of the isoxazole to that predicted for each isomer. The predicted values are calculated using a formula that utilizes Hammett constants for estimating substituent NMR-shift effects on C4. Isomer determination can also be accomplished through interpretation of the fragmentation pattern observed in the mass spectrum.
|
| Supplement |
Experimental procedures for students, notes for instructor including laboratory equipment needs, suggested requirements for the student report, CAS registry numbers for starting benzaldehydes and acetophenones, tables containing literature mp, observed mp, and CAS registry numbers for all products shown in Scheme I (including calculated and observed 13C NMR values for C4 of all isoxazoles), 13C NMR spectra of the parent isoxazole and isoxazole 6b, mass spectra of isoxazoles 4a and 4b, representative 1H NMR spectra of a chalcone, dibromide, and isoxazole, and a handout showing a number of isoxazole-containing drugs are available.
|
|
| More Information |
|
Citation |
Stephens, Chad E.; Arafa, Reem K. J. Chem. Educ. 2006 83 1336.
|
|
Keywords |
Alkenes; Hands-On Learning / Manipulatives; Heterocycles; Inquiry-Based / Discovery Learning; IR Spectroscopy; Laboratory Instruction; Mass Spectrometry; NMR Spectroscopy; Organic Chemistry; Second-Year Undergraduate; Spectroscopy; Synthesis; Upper-Division Undergraduate
|
|
History |
Created:
Last Updated: |
8/7/2006
8/18/2006
|
|
|
|
|
|
 Caution! | | Experiments, laboratory exercises, lecture demonstrations, and other descriptions of the use of chemicals, apparatus, instruments, computers, and computer interfaces are presented in the Journal of Chemical Education as illustrative of new or improved ideas or concepts in chemistry instruction and are directed at qualified teachers. Although every effort is made to assure and encourage safe practices and safe use of chemicals, the Journal of Chemical Education cannot assume responsibility for uses made of its published materials. Many chemicals are hazardous. Precautions for the safe use of hazardous chemicals and directions for their proper disposal are described in the Material Safety Data Sheets and on the labels. We strongly urge all those planning to use materials from our pages to make choices and to develop procedures for laboratory and classroom safety in accordance with local needs and situations. |
|
|
| |
|
| Home > JCE Print > Journal of Chemical Education > Issues >
2006
>
September
> Page
1336
|
|
|
| JCE HS CLIC |
|
Our Secondary School editors work hard to distill all the JCE materials to produce a fraction of particular interest to high school teachers. We call it CLIC.
|
| Contributions Welcome |
| JCE welcomes your submission |
| Advertisers |
| In recent years we have worked hard to better match our advertisers with our readers. When shopping for chemistry education materials, visit our advertisers' WWW sites first. |
| Be An Ambassador |
| Take JCE along on your outreach missions. Copies of the Journal, guest access to JCE Online, our publications catalog, and more are available for your participants. |
|
