Synthesis of five-membered heteroaromatic compounds such as pyrazoles, isoxazoles and 1,2,4-oxadiazoles are important for pharmaceutical industry and material science due to their applications. Although there are many methods to prepare such compounds, new variants continue to appear since they exhibit a wide range of biological and medicinal activities.
In this thesis, new methods were developed for the synthesis of 4-iodopyrazoles, pyrazoles, isoxazoles, 1,2,4-oxadiazoles and/or 1,2,4-oxadiazepines. In the first part of the study, electrophilic cyclization of &alpha / ,&beta / -alkynic hydrazones by molecular iodine and copper iodide were investigated as new ways for the synthesis of 4-iodopyrazoles and pyrazoles, respectively. Initially, &alpha / ,&beta / -alkynic hydrazones were prepared by the reactions of propargyl aldehydes and ketones with hydrazines. Then &alpha / ,&beta / -alkynic hydrazones were treated with molecular iodine in the presence of NaHCO3, which afforded 4-iodopyrazoles in good to excellent yields. Subsequently, the same reactions were carried out with CuI in the presence of NEt3, which furnished corresponding pyrazoles in good yields. Moreover, ferrocenyl-substituted 4-iodopyrazoles and pyrazole derivatives were synthesized from corresponding
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/12612945/index.pdf |
| Date | 01 January 2011 |
| Creators | Kivrak, Arif |
| Contributors | Zora, Metin |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | Ph.D. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for public access |
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