A new series of coumarin derivatives, 7-hydroxy-7-(trifluoromethyl)-6a,12b-dihydro-6H,7H-chromeno[3,4-c]chromen-6-ones 3a–p, were synthesized via Michael addition, transesterification and nucleophilic addition from the reaction of 3-trifluoroacetyl coumarins and phenols in the presence of an organic base. The products were characterized by infrared spectroscopy (IR), hydrogen nuclear magnetic resonance spectroscopy (1H-NMR), carbon nuclear magnetic resonance spectroscopy (13C-NMR) and high-resolution mass spectrometer (HRMS). Single crystal X-ray analysis of compounds 3a and 3n clearly confirmed their assigned chemical structures and their twisted conformations. Compound 3a crystallized in the orthorhombic system, Pbca, in which a = 8.6244(2) Å, b = 17.4245(4) Å, c = 22.5188(6) Å, α = 90°, β = 90°, γ = 90°, v = 3384.02(14) Å3, and z = 8. In addition, the mycelial growth rate method was used to examine the in vitro antifungal activities of the title compounds 3a–p against Fusarium graminearum and Fusarium monitiforme at 500 µg/mL. The results showed that compound 3l exhibited significant anti-Fusarium monitiforme activity with inhibitory index of 84.6%.

中文翻译：

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新型 6a,12b-Dihydro-6H,7H-chromeno[3,4-c] chromen-6-ones：合成、结构和抗真菌活性

通过迈克尔加成合成了一系列新的香豆素衍生物，7-羟基-7-（三氟甲基）-6a,12b-dihydro-6H,7H-chromeno[3,4-c]chromen-6-ones 3a–p， 3-三氟乙酰香豆素与苯酚在有机碱存在下反应的酯交换和亲核加成。产物经红外光谱（IR）、氢核磁共振光谱（1H-NMR）、碳核磁共振光谱（13C-NMR）和高分辨质谱（HRMS）表征。化合物 3a 和 3n 的单晶 X 射线分析清楚地证实了它们指定的化学结构和它们的扭曲构象。化合物 3a 在正交晶系 Pbca 中结晶，其中 a = 8.6244(2) Å, b = 17.4245(4) Å, c = 22.5188(6) Å, α = 90°, β = 90°, γ = 90° , v = 3384.02(14) Å3，z = 8。此外，使用菌丝体生长速率方法检测标题化合物 3a-p 对 500 µg/mL 的禾谷镰刀菌和镰刀菌的体外抗真菌活性。结果表明，化合物3l表现出显着的抗镰刀菌活性，抑制指数为84.6%。