Stereostructure of Rhodojaponin I, II, and III, Toxins of Rhododendron japonicum, and of Asebotoxin III, Toxin of Pieris japonica

Preparation of New Derivatives from α-Dihydro Grayanotoxin-II

“…A solution of 2 (63mg) in 2% KOH-SO% EtOH (S ml) was warmed at SO°C for 3 hr, neutralized with 0.2 N-HCI and worked up as usual to give a solid, which was recrystallized from EtOAc to yield 4 (38mg), mp 277°C, IR v~~~ cm-1 : 3S00 and 3440 (OH), PMR o~t~,+D20: 1.27, 1.50, 1.5S and 1.87 (3H, s, CH3 (lH, s, H-14). (6). Mild acetylation of GTX-III gave 5 in 60% yield.…”

Asebotoxin-induced centrogenic pulmonary hemorrhage in guinea pigs.

“…Asebotoxin III (ATX-III) is a diterpenoid isolated from the leaves of Asebi, Pieris japonica (1). We found in experiments using isolated papillary muscles from the heart of guinea pig that this toxin has a high cardio tonic potency (pD2, 6.8) (2).…”

Assignment of13C-NMR Spectra of Grayanotoxin-I and -III

“…The lac chemical shifts of methylene carbons of 1, 2 and their related compounds, i.e., 632 T. MASUTANI, K. KAWAZU, K. UNEYAMA, S. TORII and J. IWASA (2) A-III (4) Desacetyl A-VII (5) d'G-Analog of 3 (6) --~-~--- singlet at 15 2.20, which was unequivocally assigned to the two protons at C-15 (I5-H z ). The selective decoupling of l5-H z turned the triplet at 15 61.1 into a singlet and this led to the assignment to C-15.…”

“…asebotoxin-III (A-III) (4),41 desacetylasebotoxin-VII (desacetyl A-VII) (5)5 1 and LJ15_ analog (6) of u-dihydrograyanotoxin-II (uH 2 G-II) (3) are shown in Table I. Absence of the triplet at 15 35.8 in 4 indicates that this signal is due to C-2 of 1.…”