Insect hormones V. The structures of ponasterones B and C (original) (raw)

Insect Moulting Hormones: The Synthesis of Possible Ecdysone Precursors for Metabolic Studies

Australian Journal of Chemistry, 1974

The possible biological precursors of ecdysones, 3β-hydroxy-5β-cholest-7-en-6-one (2) and 3β,14α-dihydroxy-5β-cholest-7-en-6-one (3), are prepared from 7-dehydrocholesterol through their 5α-epimers.The corresponding 3α-[3H] derivatives of high specific activity are prepared in a similar way via 5α-cholest-7-ene-3β,6α-diol[3α-3H] 6-acetate which is obtained by reducing the corresponding 3-keto derivative with sodium borotritide.

Synthesis of silenosterone, an insect-molting hormone

Chemistry of Natural Compounds, 1999

Silenosterone is svnthesized in five steps: ace~lation of 2-desoay-a-ecdysone (1). saponification of 2-deso. tya-ecdysone-3,22-diacetate (2) to the 22-monoacetate (3), and o.~4dation of the latter to a ketone (4) and its base hydrolysis (5). The structures of the compounds are confirmed by PMR. IR spectroscopy, and mass spectromet13,.

Insect Moulting Hormones: A Study of 4-En-3-one Steroids as Possible Ecdysteroid Precursors

Australian Journal of Chemistry, 1979

The trienol ether (15) of cholesta-4,7-dien-3-one (4) is oxidized with peroxy acid mainly to the 6-hydroxy derivatives (6) and (7) and the corresponding cholesta-4,7-diene-3,6-dione (8). However, the biosynthesis of ecdysteroids may not proceed by a similar pathway since the labelled keto diene (5) was not incorporated into 20-hydroxyecdysone (10) in Calliphora stygia. None of the possible 4-en-3-one ecdysteroid precursors synthesized (6), (7), (8), (18) were active in the Calliphora assay.

Understanding insect endocrine systems: molecular approaches*

Entomologia Experimentalis et Applicata, 2000

Molecular approaches have led to spectacular improvement of our knowledge of insect endocrinology. The present review focuses on two major classes of insect lipidic hormones, ecdysteroids and juvenile hormones. Although the ecdysteroid biosynthetic pathway is not yet fully elucidated, several new steps have been recently characterized, and molecular studies of biosynthetic enzymes are now beginning. It is expected that, thanks to suitable biological models (e.g., ecdysteroid-defective mutants of Drosophila), the entire biosynthetic pathway will be elucidated in the near future. The understanding of the ecdysteroid mode of action has benefited from studies with Drosophila and major developments relate to the cascades of gene activation and the molecular basis for the stage-and tissuespecificity of hormonal effects. The biosynthetic pathway of juvenile hormones is fully known, but molecular studies of enzymes are still in their infancy, and there is some controversy about the nature of juvenile hormone receptors. Within the forthcoming years, molecular tools will allow to characterize all the enzymes involved in hormone biosynthesis and then to analyze the fine regulation of hormone titers. They will also allow comparative studies aimed at investigating the presence of related molecules (hormone biosynthetic enzymes and receptors) among other Invertebrates (Arthropods and non-Arthropods), and thus to propose evolutionary scenarios for their endocrine systems.

Presence and function of ecdysteroids in adult insects

Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology, 1984

1. Ecdysteroids have been found in both male a 2. In Diptera vitellogenin synthesis is primarily controllq synthesis can easily be induced by ecdysone and 20-OH ecdy do not directly control vitellogenin synthesis in the fat bot 3. In vivo the ovary readily takes up [3H]ecdysone from 1 releases ecdysteroids. 4. A high ecdysteroid peak was found in non-reproducing 5. Ecdysteroids do occur in adult males but the titre in tl that found in females.