ビタミンK_1の光分解(V)無酸素状態下におけるビタミンK_1の光分解産物

抄録

The solutions of vitamin K_1 in benzene or isopropanol were irradiated with mercury arc lamp in the absence of oxygen. These solutions were subjected to thin-layer chromatography using silicagel plate and chloroform as solvent to give colorless spot with Rf of 0.45 (spot 2) and yellow spot with Rf of 0.73 (spot 3). As spot 2 substance was readily oxidized, it was isolated as acetyl derivative and elucidated as 6-naphthochromenol. Spot 3 substance was separated into two spots of Rf 0.80 (spot 3-1) and 0.69 (spot 3-2) on a thin-layer plate of silicagel using n-butyl-ether・n-hexane (3 : 17) as solvent. Each substance was isolated from the degradation products by chromatographic technique and its chemical structures were elucidated In view of the identity of molecular formula, infrared and ultraviolet spectra, both substances were demonstrated to differ only in spatial arrangement and by comparison of NMR spectra in addition to these analytical data, it was concluded that spot 3-1 and 3-2 substances were trans-trans and trans-cis isomers of 1,2-bis-(2-methyl-1,4-naphthoquinone-3-yl)-1,2-bis-(2,6,10,14-tetramethyl-1-pentadecenyl)-ethane, respectively.