コムギ胚芽油および大豆油から24-メチレンシクロアルタノールの分離とそのNMRスペクトル

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A methylsterol, C31H52O, mp 120122°C, [α] 590+44.7°, Liebermann-Burchard reaction : yellow to orange-red, the acetate mp 116-117°C, [α] 590+56.9°, was isolated from the unsaponifiable matters of wheat germ oil by fractional crystallization, repeated liquid chromatography (Table 2 and 3), refining through the digitonide and subsequent recrystallization. The IR spectrum of this compound showed the presence of vinylidene group (at 3.247μ, 6.10μ and 11.29μ), cyclopropane linkage (at 3.292μ and 9.80μ or 9.97μ) and gem-dimethyl group (at 7.331μ) (Fig. 1). The properties of this compound were agreed with those of 24-methylenecycloartanol which was originally isolated from rice bran oil by Ota and Shimizu. The methylsterol was also presumed as 24-methylenecycloartanol from the NMR spectrum compared with those of cycloartenol and cycloartanol. Because, it was assumed that those substances have the same skelton structure. NMR spectrum of cycloartenol (Fig. 2) had a signal at 9.05τ (or ppm) (shown as M2), which seemed to indicate the intensity of two methyl groups, and also had two signals at 9.11τ (M3) and 9.20τ (M4) which seemed each one methyl group respectively. Besides, the signal at 8.32τ and 8.39 would be corresponded to the dimethyl group, and this signal seemed to be shifted to lower τ magnetic field by the effect of ethylene bond connected with C-25. From the spectrum of cycloartanol (Fig. 3), each signals at 9.03τ (M2), 9.09τ (M3) and 9.19τ (M4) seemed to indicate two methyl groups respectively, and those were correspended to C-4 dimethyl, C-13 methyl, C-14 methyl and C-25 dimethyl groups. The signals owing to dimethyl groups connected with C-25 which had a proton atom were shown at M3 and M4, and they were summed up to become the intensity of two methyl groups. NMR spectrum (Fig. 4) of the methylsterol, isolated in this work and being presumed as 24-methylenecycloartanol, had a signal of which intensity were equivalent to 3 methyl groups at 9.04τ (M2), and also had 3 signals at 8.93τ (M1), 9.11τ (M3) and 9.20τ (M4) respectively. Intensity of each signals was equivalent to one methyl group. Those 4 signals were derived from C-4 dimethyl, C-13 methyl, C-14 methyl and C-25 dimethyl. The signals of C-25 dimethyl had been shifted about 0.15τ to lower magnetic field, owing to the ethylene bond connected to the vicinal carbon atom of C-25. The doublet signals appeared at M1 and M2. Besides, 4 signals at around 9.56τ shown in Fig. 24 were presumed to be corresponded to methylene of cyclopropane ring. While, the authors could not get the pure compound mentioned as “tritisterols” in literature, but the properties of the crude fraction of 24-methylenecycloartanol in the refinning stage at this time, were agreed with those of “tritisterol”. As the other compoment of this oil, β-amyrin was isolated. Methylsterol, agreed with 24-methylenecycloartanol in its properties, was also isolated from soy bean oil by the similar procedures described above.
社団法人日本油化学会の論文

コムギ胚芽油および大豆油から24-メチレンシクロアルタノールの分離とそのNMRスペクトル

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