Jian‐Feng Wang

X-ray crystal structure of cytochalasin D produced by Tubercularia sp., a novel endophytic fungus of Taxus mairei

The crystal structure of cytochalasin D, which was isolated from Tubercularia sp., a novel endophytic fungus of Taxus mairei, and cocrystallized with dimethyl sulfoxide, is reported. The title compound crystallizes in the monoclinic space group P21, with a = 7.583(6) Å, b = 11.053(10) Å, c = 18.632(10) Å, β = 95.79(6)°, V = 1553.6(3) Å3, Z = 2. The structure was solved by direct methods and refined by least-squares methods to a final R factor of 0.103 for 2937 independent reflections.

1-(2,4-Di­hydroxy-3,5-di­methylphenyl)-ethano­ne (Clavatol)

To study the mechanism of formation and inhibition of Ce conversion films on Al 2024-T3 alloy, scanning microreference electrode technique (SMRE) is used to probe the potential map on Al 2024-T3 in CeCl3 solution, the localized corrosion of Al alloy decreases with immersion time and disappears finally, which results from the competition of Cl- aggression and Ce3+ inhibition on alloy surface. The results of X-ray photoelectron spectroscopy (XPS) indicate that the Ce conversion films consist of Al2O3, CeO2 and Ce2O3(Ce(OH)3), and CeO2/Ce2O3 ratio decreases with the immersion time. When a critical pH for Ce(OH)3 formation was reached, Ce(OH)3 will precipitate on the micro cathodic area on alloy surface. Consequently, H2O2, the product of the catholic reaction will oxidize a part of Ce(OH)3 to CeO2, which appears a better corrosion resistance for Al alloys.