Regioselective three-component synthesis of highly fluorescent 1,3,5-trisubstituted pyrazoles

作者：Willy Benjamin; Mueller Thomas J J

来源：European Journal of Organic Chemistry, 2008, 2008(24): 4157-4168.

DOI：10.1002/ejoc.200800444

• C-C coupling
• cyclocondensation
• fluorescence
• microwave reactions
• multi-component reactions
• pyrazoles

3,5-Disubstituted and 1,3,5-trisubstituted pyrazoles are readily synthesized from acyl chlorides, terminal alkynes, and hydrazines by a consecutive one-pot three-component Sonogashira coupling/Michael addition/cyclocondensation sequence in good to excellent yields. These pyrazoles are highly fluorescent, both in solution and in the solid state. Investigation of the electronic properties by UV/Vis and fluorescence spectroscopy and by DFT and ZINDO Cl computations reveal that the excited state is highly polar and allows fine-tuning of the absorption and emission properties. X-ray structure analyses of 3,5-disubstituted pyrazoles reveal self-organization by hydrogen bonding and pi-stacking.

• 出版日期2008-8