BODIPYS in Multicomponent Reactions. Synthesis of BODIPY-4 H -Pyran Hybrids

The Liebeskind-Srogl (LSCC) and Suzuki cross-coupling reactions were employed to prepare 10 formyl-substituted BODIPY dyes in high yields (64–98%). These derivatives were reacted with malononitrile, ethyl acetoacetate and ammonium hydroxide in a multicomponent reaction (MCR) to furnish highly substituted 4 H -pyranes. In Method A, conventional heating was employed to prepare nine such derivatives in yields that range from 25 to 72%. In Method B, six derivatives were prepared under ultrasound-activation in 35–64% isolated yields and reduced reaction times. The photophysical properties of the 4 H -pyranes thus prepared were measured. A rather low fluorescence quantum yield (Φ F = 0.61–5.67%) of the products was observed. Moreover, absorption and emission are in accordance with typical for BODIPY green-yellow region. Finally, it was observed excellent chromophore behavior (log ε max = 3.94–4.91 M –1 cm –1 ) and moderate Stokes shift values for the product series (599–728 cm –1 ), and finally 2,3,5,6-tetraarylBODIPY product with absorption and emission displaced to red (627 and 718 nm, respectively).