1 research outputs found
Total Synthesis and Biological Activity of (±)-Guignardin A, (±)-Palmarumycin B<sub>9</sub>, and Their Derivatives
A strategy for constructing an α-hydroxyl-α-acetonyl
moiety was described for the total synthesis of guignardin A (1), 8-deoxypalmarumycin B9 (2), and
palmarumycin B9 (3) via 7-, 8-, and 11-step
reactions in 14.9, 1.5, and 0.4% overall yields from 5-methoxy-1-tetralone
(1a), chroman-4-one (2a), and 2,5-dimethoxybenzaldehyde
(3a) as the starting materials, respectively. The key
steps included AlCl3- or NaSEt-mediated demethylation,
Davis oxidation, and Wacker oxidation. Their structures were characterized
by 1H and 13C NMR, HR-ESI-MS, and X-ray diffraction
data. A series of spiromamakone A monobenzo derivatives were designed
and synthesized by three diallyl-substituted byproducts via olefin
metathesis as the key step. The antifungal investigation indicated
that compounds 1l and 2n exhibited excellent
inhibitory activities against phytopathogen Rhizoctonia
solani with EC50 values of 8.68 and 5.25
μg/mL, respectively. Compound 2n had the destructive
and inhibitory effects on the morphology and growth of the hyphae
of R. solani