ビスフラボン類のメチルプロトンの核磁気共鳴スペクトルについて

概要

論文の詳細を見る
The chemical shift of methyl-proton of bisflavone derivatives in NMR spectra (in pyridine) was compared with that of apigenin series flavones (Table II) and the shifts were assigned as shown in Tables I and III. From the consideration of the chemical shift of the methoxyls at 5"- and 7"-positions in bisflavones of the biflavonyl ether type, possibility of C_4'-O-C_8" bonding in the structure of hinokiflavone (I) is denied and it is clear that the hitherto proposed bonding of C_4'-O-C_8" would be the correct one. If the bonding C_4'-O-C_8" is correct, the steric structure in Chart 1 indicates that 5"-position would receive stronger paramagnetic effect than the methoxyl in 5-position and 7"-position would receive weaker paramagnetic effect than the 7-position, which fact agrees with the values found by NMR spectral measurements.
公益社団法人日本薬学会の論文
1967-04-25