Synthesis of ß-functionalized temoporfin derivatives for an application in photodynamic therapy.

The synthesis of novel ß-functionalized derivatives of the clinically used photosensitizer Temoporfin has been achieved by nucleophilic addition reactions to a corresponding diketo chlorin. The ß-substituted dihydroxychlorin products exhibit a strong absorption in the red spectral region, a high singlet oxygen quantum yield, and were found to be highly effective in in vitro assays against HT-29 tumor cells.