T. Kamikawa

Isolation, structure and synthesis of maesanin, a host defense stimulant from an African medicinal platn maesa lanceolata

Abstract The isolation, characterization and an efficient synthesis of maesanin 1 , a host defense stimulant isolated from an African medicinal plant Maesa lanceolata is reported.

Studies on constituents of Isodon japonicus hara : The structures and absolute stereochemistry of isodonal, trichodonin and epinodosin

Abstract Seven diterpenoids have been isolated from Isodon japonicus Hara. Isodonal, trichodonin and epinodosin are formulated by chemical and spectroscopic evidence as the structures 2, 4 and 5 Antimicrobial activity has been tested.

The bitter principle of Jasminum primulinum—II : Structure and reactions of jasminim

Abstract The structure of jasminim 1 , a bitter principle of Jasminum primulinum Hemsl., based on a study of the chemical and physical properties has been confirmed by x-ray analysis.

The structure and absolute configuration of syringopicroside: A new iridoid glucoside from Syringa vulgaris L.

Abstract The structure elucidation of syringopicroside, a new iridoid glucoside from Syringa vulgaris L., is described.

Synthesis and properties of lunularic acid

Abstract Lunularic acid, a natural plant growth inhibitor, has been synthesized. A high concentration (10–30 ppm) effectively inhibited the elongation of root coleoptiles caused by 0·3 and 0·03 ppm indole-3-acetic acid.

The structure of sclerin, a metabolite of sclerotinia libertiana☆

Abstract The structure of sclerin, a new type of plant growth regulator, is shown to be II.

Synthetic studies of Jasminin

Abstract The synthesis of the methyl ester hexaacetate 4 is described. This synthesis constitutes an unambiguous proof of the structure of jasminin 1.

Reaction of 2,6-dimethyl-4-methoxybenzaldehyde with methylmagnesium iodide and some properties of the reaction products

Abstract Treatment of 2,6-dimethyl-4-methoxybenzaldehyde with MeMgI afforded two isomeric ethers, (1A and 1B), instead of the desired 1-(2,6-dimethyl-4-methoxyphenyl)ethanol. The NMR spectra of the high-melting isomer (1B) showed the presence of hindered rotation of aromatic Me groups. The reactions and properties of these ethers and other related ethers were examined.

Relationship between the furan ring and six and seven-membered lactone rings in obacunone☆

Abstract The presence of a α,β-epoxy-(β-furyl)-δ-lactone group in obacunone was suggested, from the catalytic reduction and conversion to desoxy compound of the dilactone (V), one of the oxidation products of obacunone with potassium permanganate. The stability of saturated, seven-membered lactone ring in obacunone derivatives was discussed. Degradation of the masked hydroxyl group is tertiary and is bonded to isopropyl group. Formula Ie was proposed for the partial structure of obacunone.

PLUMBAGIN AS A MODEL FOR INSECT ECDYSIS INHIBITORY ACTIVITY

Abstract An insect ecdysis inhibitor has been identified from the African shrub, Plumbago capensis (Plumbaginaceae), as the naphthoquinone “plumbagin”. Plumbagin inhibited ecdysis in four lepidopterous agricultural pest species, as well as chitin synthetase extracted from one of the four, Trichoplusiani . The synthesis and insect growth in hibitory activity of plumbagin and its analogs is discussed.