M. Koreeda

Extraction of ponasterone a and ecdysterone from podocarpaceae and related plants

Abstract A general procedure for extracting substances possessing insect moulting hormone activity, i.e., certain polyhydroxy steroids, from plant leaves is described. The screening of plants closely related to Podocarpus Nakaii for the ecdysones and ponasterones has led to the isolation of ponasterone A from P. macrophyllus , P. chinensis , and Taxus cuspidata , and the isolation of ecdysterone from P. macrophyllus and Taxus cuspidata .

The moulting hormone activity of ponasterones on Musca domestica (Diptera) and Bombyx mori (Lepidoptera)

Abstract The insect hormone activity of ponasterones A, B and C isolated from the plant, Podocarpus Nakaii HAY., has been examined using the house-fly and silkworm as test organisms. All three showed very high activity.

Stereochemistry of theaspirone and the blumenols

The stereochemistry of theaspirone (9), blumenol A (5), and blumenol B (8) has been established; a stereospecific preparation of theaspirones is also described.

Structure of ajugasterone C, a phytoecdysone with an 11-hydroxy-group

The new phytoecdysone isolated from Ajuga japonica Miq. is shown to be 2β,3β,11α,14α,20,22-hexahydroxy-5β-cholest-7-en-6-one.

The moulting hormone activity of ponasterones in the Calliphora test

Abstract The steroids ponasterone A, B, C, and D, recently isolated from podocarpacean leaves, show insect moulting hormone activity. The amounts required by the Calliphora-test are given.

RECENT STUDIES on ECDYSONES

Progress in physico-chemical methods has made it feasible to determine the structure of minor congeners, and a natural consequence of this is that a particular natural product found in a plant is usually accompanied by several other products having closely related structures.

Absolute configuration of the C18 juvenile hormone: application of a new circular dichroism method using tris(dipivaloylmethanato)praseodymium

The absolute configuration of the C18 juvenile hormone has been established as being (10R : 11S)-(I); this is based on clarification of the mode of epoxide cleavage, and a determination of the chirality of the resultant α-glycol by a new c.d. method employing Pr(dpm)3.

Structure of the norditerpene ponalactone A and its glucoside, plant growth inhibitors

Structures (I) and (V) have been established, respectively, for ponalactone A and its glucoside; both exhibit plant growth inhibitory activities.

Interaction between non-adjacent benzoate groups: an extension of the dibenzoate chirality rule

Application of the dibenzoate chirality rule to ajugasterone C and metagenin indicates that the rule can be extended to determine the chiralities of non-adjacent hydroxy-groups.