[Synthesis and antifungal activity of naturally occurring O- and C-prenylated flavanones].

Flavonoids is one of the most important groups of naturally occurring O-heterocycles possessing a wide range of biological activity. O- and C-prenylated flavanones as members of flavonoids also show remarkable biological activity such as antibacterial, antiviral, anti-tumor, antifungal, anti-HIV and enzyme inhibition activity. O- and C-prenylated flavanones possessing remarkable biological activity are representatives of this family of natural products. In this paper efficient synthetic methods have been reported for the preparation of O-(2, 3) and C-(4, 5) prenylated flavanones isolated from Monotes engleri and their analogues (26-30; 38-43) starting from commercially available starting materials. In vitro pharmacological examinations of our compounds were performed on different Candida species (Candida albicans, Candida inconspicua, Candida dubliniensis, Candida krusei) by agardiffusion method. Our structure-activity relationship study clearly showed that any modification of the structure of selinone (2) and monotesone-A (3) led to the total loss the fungistatic activity.