Substituted derivatives of 2- and 3-formylchromone were synthesized and studied by IR, 13C and 1H NMR spectroscopy and the AM1 quantum chemical method. Energy and electron distribution calculations confirm the preference of the synplanar conformation in 3-formylchromones. The calculated charges on the carbon atoms correlate well with the experimental 13C chemical shifts. Substituents bonded to the aromatic nucleus have only small effect on the electron structure of the pyrone ring.
对2-和3-甲酰基
香豆素的衍
生物进行了合成和研究,通过红外光谱、
13C和
1H核磁共振光谱以及
AM1量子
化学方法进行了研究。能量和电子分布计算证实了3-甲酰基
香豆素中synplanar构象的优先性。计算得到的碳原子的电荷与实验中的
13C
化学位移很好地相关。芳香核上的取代基对
吡喃环的电子结构仅有轻微影响。