Synthesis of 4-iodopyrazole derivatives

Download

index.pdf

Date

2008

Author

Yazıcı, Ceyda

Metadata

Show full item record

Item Usage Stats

183
views

62
downloads

Pyrazoles have been studied for over a century as an important class of heterocyclic compounds and continue to attract considerable interest due to the broad range of biological activities they possess. The electrophilic cyclization of the acetylenic hydrazones initiated by molecular iodine could provide new ways of synthesizing biologically active 4-iodopyrazole derivatives, which are important precursors for the synthesis of highly substituted pyrazole derivatives. For this reason, we investigated the synthesis of 4-iodopyrazole derivatives, such as 1-aryl- 5-alkyl/aryl-4-iodopyrazoles, starting from phenylhydrazine and , -acetylenic aldehyde derivatives. Initially, , -acetylenic aldehydes were synthesized by formylation reaction of corresponding alkynes with DMF. Then, hydrazone derivatives of these aldehydes were prepared by heating them with phenylhydrazine in a neat manner at 55 °C for 5 h. Finally, acetylenic phenyl hydrazone derivatives were subjected to electrophilic cyclization by treating with excess molecular iodine at 80 °C for 3 h. Although electrophilic cyclization is commonly used in organic chemistry, it has not been employed for the cyclization of acetylenic phenyl hydrazones to pyrazole derivatives. Under optimized conditions, these reactions afforded 1-aryl-5-alkyl/aryl-4-iodopyrazole derivatives in moderate to good yields as the single or the major product of the reactions. In some cases, 1-aryl-5-alkyl/arylpyrazole derivatives resulted from these reactions as minor products. In conclusion, 4-iodopyrazole derivatives were synthesized for the first time directly from acyclic starting materials, , -acetylenic phenylhydrazones and iodine, via electrophilic cyclization.

Subject Keywords

Chemistry., Acetylene.

URI

http://etd.lib.metu.edu.tr/upload/3/12609750/index.pdf
https://hdl.handle.net/11511/17719

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Synthesis of ferrocenyl substituted quinolines Velioğlu, Özlem; Zora, Metin; Department of Chemistry (2008) Quinolines have been studied for over a century as an important class of heterocyclic compounds and continue to attract considerable interest due to the broad range of biological activities they possess. The incorporation of the essential structural features of quinolines with a ferrocene moiety could provide new derivatives with unexpected and/or enhanced biological activities since several ferrocene derivatives have already been shown to be active against a number of tumors. For this reason, we investigat...
Synthesis of ferrocenyl substituted pyrazoles Görmen, Meral; Zora, Metin; Department of Chemistry (2005) Pyrazoles have been studied for over a century as an important class of heterocyclic compounds and continue to attract considerable interest due to the broad range of biological activities they possess. The incorporation of the essential structural features of pyrazoles with a ferrocene moiety could provide new derivatives with unexpected and/or enhanced biological activities since several ferrocene derivatives have already been shown to be active against a number of tumors. For this reason, we investigated...
Chemoenzymatic synthesis of 2-ethyl-5-hydroxy-3- methoxy-cyclopent-2-enone Dalfidan, Çağla; Demir, Ayhan Sıtkı; Department of Chemistry (2005) Chiral hydroxylated cyclopentane derivatives are important precursors for biologically active compounds. Synthesis of these types of compounds in optically pure form found increased interest in pharmaceutical chemistry. 2-ethyl-cyclopentane-1.3-dione was acetoxylated using manganese III acetate at preferred positions. Enzyme catalyzed enantioselective hydrolysis or enantioselective acetoxylation of hydrolyzed acetoxy derivatives gives the corresponding hydroxylated diketones in optically pure form.
Synthesis of 5-ferrocenyl-4-((4-nitrophenyl)sulfenyl)-1H-pyrazoles by electrophilic cyclization Karahan Dağ, Fulya; Zora, Metin; Department of Chemistry (2011) Pyrazoles have been intensely studied in the design and synthesis of biologically active agents because they display considerable medicinal activities. Recent studies have shown that integration of a ferrocenyl unit with structural features of pyrazoles can result in the formation of the new products with enhanced or/and unexpected biological activity since several ferrocene derivatives have already been illustrated to be active against a number of tumors. Therefore, we have investigated the electrophilic c...
Addition of carbonyl compounds to the cyclic olefins : synthesis of cyclitols Altun, Yasemin; Balcı, Metin; Department of Chemistry (2008) Cyclitols have attracted a great deal of attention in recent years owing to biological activities exhibited by them and also their usefulness in the synthesis of other natural products and pharmaceuticals. Carbasugars are also a derivative of cyclitols and they are cyclic monosaccharide analogues which posses CH2OH group in their structure. In this study, novel synthetic strategies leading to cyclitol derivatives were investigated and the synthesis of tetraol (72) and pentaol (73) derivatives containing CH2...

Citation Formats

C. Yazıcı, “Synthesis of 4-iodopyrazole derivatives,” M.S. - Master of Science, Middle East Technical University, 2008.