Flavone-Nitrogen Heterocycle Conjugate Formation by 1,3-Dipolar Cycloadditions

作者：Sousa Regina M S; Pinto Diana C G A; Silva Artur M S^*; Serra Vanda Vaz; Barros Ana I R N A; Faustino Maria A F; Neves Maria G P M S; Cavaleiro Jose A S

来源：European Journal of Organic Chemistry, 2012, (1): 132-143.

DOI：10.1002/ejoc.201101185

• Nitrogen heterocycles
• Flavones
• Porphyrinoids
• Ylides
• Cycloaddition
• Medicinal chemistry

Azomethine ylides generated in situ from the reaction of N-[2-,3- and 4-(chromon-2-yl)phenyl] glycine and paraformaldehyde can be trapped with dipolarophiles in 1,3-dipolar cycloaddition reactions to yield flavone-nitrogen heterocycle dyads. These azomethine ylides proved to be reactive with electron-poor dipolarophiles, affording the expected adducts. The use of microwave irradiation as an alternative source of heating has significant advantages and allows a reduction of both reaction time and temperature. The use of benzaldehydes as dipolarophiles afforded flavone-oxazolidine dyads, and the results indicate that electron-withdrawing groups in the para position of the benzaldehyde increases the dipolarophile reactivity. This work was also extended to the use of meso-tetrakis(pentafluorophenyl) porphyrin as a dipolarophile, allowing new flavone-dihydroporphyrin conjugates to be prepared.

• 出版日期2012-1