Antifungal and antioomycete activities and modes of action of isobenzofuranones isolated from the endophytic fungus Hypoxylon anthochroum strain Gseg1.

Hypoxylon species are distributed worldwide and have been isolated from different habitats. The endophyte Hypoxylon anthochroum strain Gseg1 was isolated from healthy leaves of Gliricidia sepium. A chemical study of the culture medium and mycelium organic extracts of the endophytic fungus H. anthochroum Gseg1 led to the isolation of three known isobenzofuranones, 7-hydroxy-4,6-dimethyl-3H-isobenzofuran-1-one, 1, 7-methoxy-4,6-dimethyl-3H-isobenzofuran-1-one, 2, 6-formyl-4-methyl-7-methoxy-3H-isobenzofuran-1-one, 3, and one compound was isolated for the first time as a natural product, 7-methoxy-4-methyl-3H-isobenzofuran-1-one, 4. In addition, the chemical synthesis of 1 and 2, and a derivative, 7-methoxy-6-methyl-3H-isobenzofuran-1-one, 5, was performed. The isobenzofuranones showed antifungal and antioomycete activities. Compounds 1-5 inhibited the growth of Fusarium oxysporum, Alternaria alternata, Pythium aphanidermatum, and Phytophthora capsici, in addition, 1, 2 and 5 interrupted the respiration and caused electrolyte leakage due to cell membrane damage. Compound 2 was the most active, inhibiting the growth of the four microorganisms, affecting the respiration and increasing the relative conductivity due to electrolyte leakage. Compounds 1-4 also induce morphological changes in the plant pathogens' mycelia and hyphae. These compounds could be useful for the control of plant pathogenic fungi and oomycetes of agricultural relevance.

Aluminum complexes with new non-symmetric ferrocenyl amidine ligands and their application in CO2 transformation into cyclic carbonates.

A set of alkyl aluminum complexes supported by non-symmetric ferrocenyl amidine ligands were used as catalysts for the preparation of cyclic carbonates from epoxides and carbon dioxide using Bu4NI as a co-catalyst. A modified method for the synthesis of aminoferrocene allowed us to obtain this precursor in quantitative yield. Treatment of aminoferrocene with the corresponding acetimidoyl chloride afforded the desired ferrocenyl amidine ligands L1H, (E)-N-(2,6-diisopropylphenyl)-N'-(ferrocenyl)acetimidamide, and L2H, (E)-N-(2,6-dimethylphenyl)-N'-(ferrocenyl)acetimidamide. The reaction of these ligands with 1.0 or 0.5 equiv. of AlMe3 led to the synthesis of aminoferrocene based aluminum complexes ((L1)AlMe2 (1), (L2)AlMe2 (2), (L1)2AlMe (3), and (L2)2AlMe (4)) in excellent yields, which were characterized by spectroscopic and X-ray diffraction methods. In addition, we have studied their electrochemical properties and complex 1 was found to be the most active catalyst for the formation of cyclic carbonates 6a-j from their corresponding epoxides 5a-j and CO2.