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对 1 4个合成的 B环对位取代异黄酮化合物核磁共振氢谱进行了研究 .利用超导核磁共振归属了 B环无取代异黄酮质子的化学位移 ,根据取代基化学位移的变化影响规律考察了取代基对分子的影响方式 .研究结果表明 ,2 ( 6 ) ,3 ( 5 )位质子共振迁移分别与取代基参数σp 和 So 线性相关 ,说明 4 位取代基主要通过电子效应影响其间位质子 ,其磁各向异性仅影响邻位质子 ,该取代基对 A环质子影响不大 ,而对 C环尤其是对 2 -H影响较明显 .
Nuclear magnetic resonance (1H NMR) spectra of para-substituted isoflavones were synthesized from 14 synthetic B-rings and their chemical shifts were assigned to the protons of B-substituted isoflavones by superconducting NMR. The influence of chemical shifts on substituents was investigated The results show that the 2 (6), 3 (5) proton resonances migrate linearly with the substituent parameters σp and So, respectively, indicating that the 4 substituents mainly affect the intermolecular protons , Its magnetic anisotropy only affects the ortho protons. The substituent has little effect on the A ring protons, but has a more obvious effect on the C ring, especially on 2 -H.