Four New 2-Pyrones from Fusarium tricinctum, an Endophytic Fungus of Ligusticum chuanxiong

Abstract

By silica gel, Sephadex LH-20 column chromatography as well as preparative high performance liquid chromatography (HPLC), four previously undescribed α-pyrones sharing same primary structure were isolated from the brown rice solid medium of Fusarium tricinctum. Their structures were elucidated by spectroscopic analyses and their absolute configurations were finally confirmed by a modified Snatzke's method. Keywords 2-pyrone; Fusarium tricinctum; Ligusticum chuanxiong; induced circular dichroism Results and discussionCompound 1 was obtained as yellow oil. The HRESIMS ion at m/z 199.0948 [M＋H ＋ ] indicated its molecular formula should be C 10 H 14 O 4 (calculated for C 10 H 15 O 4 [M＋

Aureonitol Analogues and Orsellinic Acid Esters Isolated from Chaetomium elatum and Their Antineuroinflammatory Activity

“…CD comparison showed that the absolute configurations of the chiral carbons in the tetrahydrofuran moiety of 6 are 5 S , 6 R , and 7 S . As the Mo 2 -erythro-vic-diols complex can generate two favored conformations, which can cause opposite optical rotations, Cotton effects produced by the Mo 2 -threo-vic-diols complex should be stronger than those yielded by the Mo 2 -erythro-vic-diols complex when samples are measured at the same concentration . Herein, the ICD spectra of both 5 and 6 show negative signs at bands II and IV, clarifying the absolute configurations of the two compounds.…”

“…In 9 , the chemical shifts of C-1′ (Δ δ = +2.4 ppm), C-3′ (Δ δ = +4.6 ppm), and C-5′ (Δ δ = +4.9 ppm) are significantly deshielded, and those of C-2′ (Δ δ = −5.1 ppm) and C-4′ (Δ δ = −3.0 ppm) are shielded. Therefore, 9 was deduced to be an epimer of globosumone C. As the relative configurations of the vic-diol group in globosumone C is erythro, the relative configurations of hydroxy groups at positions 3′ and 4′ in 9 were deduced as threo. The ICD spectrum (Figure ) of 9 shows negative Cotton effects at bands II and IV.…”

“…The CD spectra of 4 – 9 were first recorded, and the ICD spectra of Mo complexes of 4 – 9 were obtained following the procedure reported in our previous work . Compounds 4 – 9 (each 0.5 mg) and Mo 2 (OAc) 4 (1.0 mg) were dissolved in 1.0 mL of dry DMSO to form a solution.…”