3 ホウライカヅラ(Gardneria nutans Sieb. et Zucc.)よりのIndole系アルカロイド

抄録

The isolation of four tertiary basis from Gardneria nutans Sieb. et Zucc. is described. (Table 1) The Mass spectra of a main alkaloid gardnerine (I) is simlar to that reported for polyneuridine. Also the chemical reactivity of (I) is very close with 21-deoxyajmalol-A (IX) such were shown Fig-1 and 2. Upon oxidation with CrO_3, (I) was transformed into a product (VII). Upon reduction with LiAlH_4, this compound (VII) reverted to gardnerine (I), which a convertion is shown corrected structure of (VII). The both compounds of (VII) and gardnutine were identified by I.R. and Mass spectra. Isolation of 6-oxygenated sarpagine type alkaloid is the first case as natural product. The third alkaloid hydroxygardnutine (XVII) (Fig. 5) is transformed with hydrogenolysis to dihydrogardnutine (XXI), which was obtained from gardnutine (VII) by catalytic reduction. Also it is pointed out C-18 hydroxyl group on (XVII) that NMR spectra of (XX) has shown 5.41τ (doublet J=7 cps, 1H) and 4.57τ (tripled J=7 cps, 2H) as acetoxy-ethylidene group.