Nejvíce citovaný článek - PubMed ID 10841475
- MeSH
- fotolýza MeSH
- molekulární struktura MeSH
- organické látky chemie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
- Research Support, N.I.H., Extramural MeSH
- Názvy látek
- organické látky MeSH
A clean bifurcation between two important photochemical reactions through competition of a triplet state Type II H-abstraction reaction with a photo-Favorskii rearrangement for (o/p)-hydroxy-o-methylphenacyl esters that depends on the water content of the solvent has been established. The switch from the anhydrous Type II pathway that yields indanones to the aqueous-dependent pathway producing benzofuranones occurs abruptly at low water concentrations (~8%). The surprisingly clean yields suggest that such reactions are synthetically promising.
- MeSH
- benzenové deriváty chemie MeSH
- benzofurany chemická syntéza chemie MeSH
- estery MeSH
- fotochemické procesy MeSH
- indany chemická syntéza chemie MeSH
- rozpouštědla MeSH
- voda chemie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
- Názvy látek
- benzenové deriváty MeSH
- benzofurany MeSH
- estery MeSH
- indany MeSH
- rozpouštědla MeSH
- voda MeSH
A broadly based investigation of the effects of a diverse array of substituents on the photochemical rearrangement of p-hydroxyphenacyl esters has demonstrated that common substituents such as F, MeO, CN, CO2R, CONH2, and CH3 have little effect on the rate and quantum efficiencies for the photo-Favorskii rearrangement and the release of the acid leaving group or on the lifetimes of the reactive triplet state. A decrease in the quantum yields across all substituents was observed for the release and rearrangement when the photolyses were carried out in buffered aqueous media at pHs that exceeded the ground-state pKa of the chromophore where the conjugate base is the predominant form. Otherwise, substituents have only a very modest effect on the photoreaction of these robust chromophores.
- Klíčová slova
- pH, pKa, photorelease, solvent effects, substituent,
- Publikační typ
- časopisecké články MeSH
