The photochemistry of trans-1-o-hydroxyphenyl-2-phenylcyclopropane, trans-1, was studied under a variety of experimental conditions. Direct irradiation through quartz in cyclohexane gave rise mainly to ring-expanded products, 2-phenyl-3,4-dihydro-2H-benzopyran, 2, 2-benzyl-2,3-dihydrobenzofuran, 3, and 1-o-hydroxyphenylindan, 4. The major products, 2 and 3, are rationalized by intramolecular proton transfer. However, a significant fraction of 3 is formed via ring-opening to cinnamylphenol, 5. An additional product, o-(alpha-cyclohexylmethyl)phenol, 7, suggests fragmentation of trans-1 and (formal) insertion of o-hydroxyphenylcarbene into cyclohexane. Direct irradiation in methanol produced methanol adducts 8 and 9 instead of 2, 3, 4, or 7. Finally, acetone-sensitized irradiation of trans-1 resulted in geometric isomerization to cis-1; this result can be rationalized via a biradical intermediate.

The interaction dynamics between the drug flurbiprofen (FBP) and human serum albumin (HSA) has been investigated by time-resolved fluorescence spectroscopy, combining femtosecond fluorescence upconversion and picosecond time-correlated single photon counting. In order to obtain additional information on the drug/ protein interaction, several covalently linked model dyads, composed of FBP and tryptophan or tyrosine, were also studied. For all systems, the main feature was a remarkable dynamic FBP fluorescence quenching, more prominent in the dyads than in the protein complex. All systems also displayed a clear stereoselectivity depending on the (S)- or (R)-form of FBP, that was strongly influenced by the conformational arrangement of the investigated chromophores.

No abstract