A synthesis of tetrasubstituted pyrazoles containing two, three or four pyridinyl substituents is described. Hence, the reaction of 1,3-dipyridinyl-1,3-propanediones with 2-hydrazinopyridine or phenylhydrazine, respectively, affords the corresponding 1,3,5-trisubstituted pyrazoles. Iodination at the 4-position of the pyrazole nucleus by treatment with I/HIO gives the appropriate 4-iodopyrazoles which served as starting materials for different cross-coupling reactions. Finally, Negishi cross-coupling employing organozinc halides and Pd catalysts turned out to be the method of choice to obtain the desired tetrasubstituted pyrazoles. The formation of different unexpected reaction products is described. Detailed NMR spectroscopic investigations (H, C, N) were undertaken with all products prepared. Moreover, the structure of a condensation product was confirmed by crystal structure analysis.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5433223 | PMC |
| http://dx.doi.org/10.3762/bjoc.13.90 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Encapsulation of Candida antarctica lipase B in metal-organic framework under ultrasound and using it to one-pot synthesis of 1,3,4,5-tetrasubstituted pyrazoles.
Bioprocess Biosyst Eng
December 2024
Department of Organic Chemistry, Faculty of Chemistry, Shahid Beheshti University, Tehran, G.C, Iran.
Encapsulating the enzyme in metal-organic frameworks (MOFs) is a convenient method to prepare MOF-enzyme biocomposite. In this study, Candida antarctica lipase B (CAL-B) was chosen to immobilize in Cu-BTC MOF under ultrasound irradiation. CAL-B was immobilized in Cu-BTC under ultrasound at 21 kHz and 11.
View Article and Find Full Text PDFA Highly Potent, Orally Bioavailable Pyrazole-Derived Cannabinoid CB2 Receptor- Selective Full Agonist for Studies.
ACS Pharmacol Transl Sci
August 2024
Institute of Biochemistry and Molecular Medicine, University of Bern, Bern 3012, Switzerland.
The cannabinoid CB2 receptor (CB2R) is a potential therapeutic target for distinct forms of tissue injury and inflammatory diseases. To thoroughly investigate the role of CB2R in pathophysiological conditions and for target validation , optimal pharmacological tool compounds are essential. Despite the sizable progress in the generation of potent and selective CB2R ligands, pharmacokinetic parameters are often neglected for studies.
View Article and Find Full Text PDFNovel tetrasubstituted 5-Arylamino pyrazoles able to interfere with angiogenesis and Ca mobilization.
Eur J Med Chem
October 2024
Department of Pharmacy, Section of Medicinal Chemistry, University of Genoa, Viale Benedetto XV 3, I-16132, Genova, Italy. Electronic address:
In the last years, 5-pyrazolyl ureas and 5-aminopyrazoles have been investigated for their antiangiogenetic properties and their potential interaction with the ubiquitous Ca binding protein Calreticulin. Based on the structure of the active compounds I and GeGe-3, novel 5-arylamino pyrazoles 2 and 3 were synthesized through a stepwise procedure. In MTT assays, all the new derivatives proved to be non-cytotoxic against eight different tumor cell lines, normal fibroblasts, and endothelial cells.
View Article and Find Full Text PDFA highly potent, orally bioavailable pyrazole-derived cannabinoid CB2 receptor-selective full agonist for studies.
bioRxiv
April 2024
Institute of Biochemistry and Molecular Medicine, University of Bern, Bern 3012, Switzerland.
The cannabinoid CB2 receptor (CB2R) is a potential therapeutic target for distinct forms of tissue injury and inflammatory diseases. To thoroughly investigate the role of CB2R in pathophysiological conditions and for target validation , optimal pharmacological tool compounds are essential. Despite the sizable progress in the generation of potent and selective CB2R ligands, pharmacokinetic parameters are often neglected for studies.
View Article and Find Full Text PDFVisible light-induced organo-photocatalyzed route to synthesize substituted pyrazoles.
Org Biomol Chem
March 2024
Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741246, India.
Article Synopsis
- The synthesis of tetra-substituted pyrazoles is achieved through a new method involving organo-photocatalyzed decarboxylative intramolecular cyclization using 1,2-diaza-1,3-dienes and α-ketoacids.
- This method is notable for being metal-free and oxidant-free, which results in shorter reaction times and milder conditions.
- The technique enhances the ability to create different pyrazole derivatives, broadening possibilities for future research and applications in various scientific areas.
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!