Masaaki Katai

Crystal and molecular structure of 10,20-epoxy-grayanotoxin-II

The photooxidation with HgO in benzene and the hydrolysis with 2%-KOH in methanol of the grayanotoxin (GTX) derivative (4) gave a 10,20-epoxy-grayanotoxin-II(5). The crystal structure of (5) has been determined by X-ray diffraction at room temperature. The crystal is monoclinic, space group P21, with a = 14.248(10) Å, b = 6.670(10) Å, c = 9.990(10) Å, α = 105.507(8)°, V = 914.9(2) Å3, Z = 2. The structure was solved by direct methods and refined by full-matrix least squares methods to a final R1 = 0.046 (wR2 = 0.0833) for 1161 independent reflections. The molecule has a pentacyclic structure consisting of two five-membered, one six-membered, one seven-membered, and one three-membered rings. The three-membered ring is connected with the seven-membered ring by spiro-type bond.

Crystal and molecular structure of grayanotoxin VII

The crystal and molecular structure of a grayanotoxin VII is presented. The crystal is monoclinic, space group P21, with a = 7.647(1) Å, b = 11.7591(7) Å, c = 10.0873(6) Å, β = 91.143(8)°, V = 906.9(1) Å3, Z = 2. The structure was solved by direct methods and refined by full-matrix least-squares methods to a final R = 0.057 for 1494 independent reflections. The molecule has a tetracyclic structure consisting of two five-membered, one six-membered, and one seven-membered rings.

Crystal and molecular structure of a new diterpenyl glycoside from Pteris cretica L.

The crystal and molecular structure of a new diterpenyl glycoside, Ptr-1, is presented. The crystal is triclinic, space group P1, with a = 8.2414(8) Å, b = 13.0826(9) Å, c = 6.1427(8) Å, α = 95.345(9)°, β = 111.589(8)°, γ = 96.726(7)°, V = 604.9(1) Å3, Z = 1. The structure was solved by direct methods and refined by full-matrix least-squares methods to a final R = 0.049 (Rw = 0.099) for 1872 independent reflections. The molecular structure is based on a glycopyranosyl group and a tetracyclic group. The glycopyranosyl group is β-D-allopyranosyl group. The tetracyclic group consists of 1 five-membered and 3 six-membered rings.

Crystal and molecular structure of iso-grayanotoxin II

AbstractThe crystal and molecular structure of a grayanotoxin derivative, iso-grayanotoxin II, is presented. The crystal is orthorhombic, space group

Triterpenoids of the Bark of Pieris japonica D. DON (Japanese Name : Asebi). II. 13C Nuclear Magnetic Resonance of the γ-Lactones of Ursane- and Oleanane-type Triterpenes

P2_1 2_1 2_1 ,{\text{ with }}a{\text{ = 12}}{\text{.357(1) }}{\AA}{\text{, }}b{\text{ = 23}}{\text{.354(1) }}{\AA}{\text{, }}c = 6.284(2){\text{ }}{\AA}{\text{, }}V = 1813.3(6)\,{\AA}^3 {\text{, }}Z = 4

Studies on the Constituents of the Leaves of Pieris japonica D. DON

. The molecule is based on a tetracyclic structure consisting of two five-membered, one six-membered, and one seven-membered rings with various conformations.

[Studies on the constituents of the leaves of Pieris japonica D. don. IV. The isolation and the structure of pieristoxin F, pieristoxin G and several toxic components (author's transl)].

The crystal and molecular structure of a grayanotoxin III derivative, 6-0-acetylgrayanotoxin III is presented. The crystal is orthorhombic, space group P212121, witha=15.582(3),b=21.304(3),c=6.339(3)Å,V=2104(1) Å3Z=4. The structure was solved by direct methods and refined by full matrix least-squares methods to a finalR=0.047 for 1763 independent reflections withF0>3 σ (F0) The molecule is based on a tetracyclic structure consisting of two five-membered, one six-membered, and one seven-membered ring with various conformations.