Two novel flavonoid derivatives 5 and 6 were synthesized and characterized by IR, 1H, 13C NMR spectroscopy and mass spectrometry. The core structure of the two flavonoids was constructed by applying Baker-Venkataraman rearrangement on 2-acylphenyl ester intermediate. The two compounds exhibited remarkable UV-visible absorption activities compared to flavone. Flavonoid 5 showed a bathochromic shift of 75.6 nm when the size of the cinnamic acid was increased by phenylbutadienyl group and hence it is a good UVA sunscreen. The 4-nitrostyryl group introduced in the cinnamic acid subchromophore of flavonoid 6 causes the compound to absorb at 308.3 and at 345.8 nm which will make it a broad-spectrum sunscreen.
两种新型黄
酮类衍
生物5和6被合成并通过红外光谱、核磁共振氢谱和碳谱以及质谱进行了表征。这两类
黄酮的核心结构是通过在2-酰基苯酯中间体上应用Baker-Venkataraman重排构建的。与
黄酮相比,这两种化合物展示了卓越的紫外-可见吸收活性。
黄酮5在增加
肉桂酸结构中的苯
丁二烯基团后,其吸收峰向长波方向移动了75.6纳米,因此它是一种优秀的UVA防晒剂。在
黄酮6的
肉桂酸亚显色团中引入
4-硝基苯乙烯基团,使得该化合物在308.3纳米和345.8纳米处有吸收,这将使其成为一种广谱防晒剂。