RESUMO
An enantioselective total synthesis of the natural (+)-linoxepin (1) was accomplished in eleven steps from bromovanin (24). Key steps are a domino carbopalladation/ Mizoroki-Heck reaction with the formation of a pentacyclic system, an asymmetric hydroboration as well as an oxidative lactonization.
Assuntos
Benzaldeídos/química , Lignanas/química , Lignanas/síntese química , Compostos Policíclicos/química , Compostos Policíclicos/síntese química , Estrutura Molecular , Oxirredução , EstereoisomerismoRESUMO
A main problem of common cancer chemotherapy is the occurrence of severe side effects caused by insufficient selectivity of the applied drugs. A possible concept to overcome this limitation is light-driven prodrug monotherapy. The synthesis as well as photochemical and biological evaluation of new photoactivatable prodrugs is described. Best results were obtained with prodrug (S,S)-7a. The photochemical labile protecting groups in (S,S)-7a can easily be removed by irradiation with UV-A light in 30 min with a power of only 2 J cm(-2). The determination of the in vitro cytotoxicity by using an HTCFA-test reveals a QIC(50) value of 8200 and the prodrug is more than two million times less cytotoxic than the corresponding seco-drug (-)-(S,S)-5 with an IC(50) value of about 110 fM. The big therapeutic window makes (S,S)-7a very suitable for its use in selective cancer therapy.