Makoto Takai

New peptide alkaloids from Hovenia dulcis and H. tomentella

Abstract From the root bark of Hovenia dulcis Thunb. and H. tommentella (Makino) Nakai (Rhamnaceae), three peptide alkaloids, frangulanine, hovenins- A and - B have been isolated. Hovenin- A has been shown to be des- N -methylfrangulanine (II).

New triterpenoids from the leaves of Tetrapanax papyriferum

Four new triterpenoids, papyriogenins D (3), E (4), F (5), and G (6), isolated from ether extracts of the fresh leaves of Tetrapanax papyriferum(Araliaceae), were identified as 21α-hydroxy-3-oxo-oleana-11,13(18)-dien-28-oic acid, 3α,21α-dihydroxyoleana-11,13(18)-dien-28-oic acid, 3α-hydroxy-21-oxo-olean-12-en-28-oic acid, and 3α,21α-dihydroxyoleana-11,13(18)-dieno-22β,28-lactone, respectively, by spectroscopic evidence and chemical correlations.

A new triterpenoid glycoside from the leaves of Tetrapanax papyriferum

A new triterpenoid glycoside isolated from the leaves of Tetrapanax papyriferum by using droplet counter-current chromatography and silica gel column chromatography was identified as 11α-methoxy-3,21-dioxo-olean-12-en-28-oyl α-L-rhamnopyranosyl-(1 → 4)-β-D-glucopyranosyl-(1 → 6)-β;-D-glucopyranoside.

Biochemical Studies on “Bakanae” Fungus: Part XXXIV. Isolation of Gibberellins and Their PropertiesPart XXXV.Relation between Gibberellins, A1, A2and Gibberellic Acid

Gibberllin A and B,1,2) the metabolic products of Gibberella fu jikuroi which cause abnormal growth of young tissues of higher plants, were isolated and further investigation to elucidate the chemical structure have been published already3,4, 5,6,7), Gibberellin A, isolated through the process shown in Fig. 1, was chromato gramed on paper using various solvents, butanol-NH3aq, ethanol-NH3aq, benzene acetic acidwater, ethanol-ethyl acetate ligroin, ethanol-ethyl acetate-bezene, but anol saturated with water, but in every case only one spot was found. Further, as the results of the thirty plates count ercurrent distribution method using the solvent system of ethyl. acetate and one mole phosphate buffer adjusted to pH 5.3, we found only one peak. From these

X-Ray crystal structure analysis of papyriogenin A

The crystal structure of a new oleanane type triterpene, papyriogenin A, has been shown by X-ray analysis to be 3,21-dioxo-oleana-11,13(18)-diene-28-oic acid.

X-Ray analysis of tri-N-methylfrangulanine methiodide

The crystal structure of a peptide alkaloid derivative, tri-N-methylfrangulanine methiodide, is reported.

Evaluation of O,O-dialkyl O-cyanophenyl phosphates and phosphorothioates as insecticides.

Various O,O-dialkyl O-cyanophenyl phosphates and phosphorothioates were prepared and their biological activities were examined. Among them, O,O-dimethyl O- (4-chloro-2-cyanophenyl) phosphorothioate was found to have selective and high toxicity to houseflies. O,O-Dimethyl O- (4-cyanophenyl) phosphorothioate, O,O-diethyl O- (4-cyanophenyl) phosphorothioate and O,O-diethyl O- (2-chloro-4-cyanophenyl) phosphorothioate showed high insecticidal activty to American cockroaches, though the former two were not so effective to houseflies. The dimethyl esters of these series exhibited markedly lowered mammalian toxicity. Among the O-ethyl O-cyanophenyl phenylphosphonothioates, O-ethyl O- (2-chloro-4-cyanophenyl) phenylphosphonothioate was highly effective to mites, while less effective to insects.

Biochemical Studies on “Bakanae” Fungus. Part 51–53: Chemical Structure of Gibberellins. Part XVII.Chemical Structure of Gibberellins. Part XVIII.Chemical Structure of Gibberellins. Part XIX.

The outline of this report has already been published in this Journal as a communication to the Editors. The relation among four isomers, gibberellin A1, gibberellin C, pseudogibberellin A1 and isogibberellin A1 was clarified. The partial structure of gibberellin C is presented.

13. Biochemical Studies on "Bakanae" Fungus:Part 33. 5-Hydroxymethyl-furan-2-carboxylic acid

In the study on the chemical structure of gibberellins, the submerged culture method was applied to obtain a large amount of gibberellins. While isolating them from the medium, a crystal having m.p. 164-5° was obtained and identified to be 5-hydroxy-methyl-2-furan-carboxylic acid.