Insect juvenile hormones synthesis

WS, Feyereisen R (1998) A cytochrome P450 terpenoid hydroxylase linked to the suppression of insect juvenile hormone synthesis. Proc Natl Acad Sci U S A 95 12884-12889... 

Cinnamyl—sesamol ethers, eg (35), are useful as insect chemosterilants (111). 3,4-Methylenedioxyphenyl-3-halo-2-propynyl ethers (36, X = halogen) are synergists for carbamate insecticides (112). HaloaLkyl or haloalkenyl ethers, eg (37), show acaricidal and insect juvenile hormone activity (113). The first total synthesis of gibbereUic acid was from 2-methoxy-6-aLkoxyethyl-l,4-benzoquinone, a derivative of hydroxyhydroquinone (114). 

Stay, B. (2000). A review of the role of neurosecretion in the control of juvenile hormone synthesis a tribute to Berta Scharrer. Insect Biochemistry and Molecular Biology 30 653-662. 

In addition to its role as an intermediate in cholesterol biosynthesis, isopentenyl pyrophosphate is the activated precursor of a huge array of biomolecules with diverse biological roles (Fig. 21-48). They include vitamins A, E, and K plant pigments such as carotene and the phytol chain of chlorophyll natural rubber many essential oils (such as the fragrant principles of lemon oil, eucalyptus, and musk) insect juvenile hormone, which controls metamorphosis dolichols, which serve as lipid-soluble carriers in complex polysaccharide synthesis and ubiquinone and plastoquinone, electron carriers in mitochondria and chloroplasts. Collectively, these molecules are called isoprenoids. More than... 

Fan Y., Rafaeli A., Gileadi C., Kubli E. and Applebaum S. W. (1999b) Drosophilia melanogaster sex peptide stimulates juvenile hormone synthesis and depresses sex pheromone production in Helicoverpa armigera. J. Insect Physiol. 45, 127-133. 

Schal C., Chiang A-S., Burns E. L., Gadot M. and Cooper R. A. (1993). Role of the brain in juvenile hormone synthesis and oocyte development effects of dietary protein in the cockroach Blattella germanica (L.). J. Insect Physiol. 39, 303-313. 

Although the past three years have witnessed many ingenious syntheses of the two insect juvenile hormones, the preparation of the naturally-occurring dextrorotatory Cl8 hormone (cis-epoxide) has only recently been achieved. Indeed, in two independent studies, both enantiomeric pairs of the cis- and trans-epoxides. have been prepared and it has been firmly established that the two chiral centres have the 10R,11S configurations in the naturally-occurring material. Findlay et al. have now published full details of their previously announced synthesis of the two juvenile hormones and other double-bond isomers. In an earlier synthesis of the C18 hormone, Corey et al. used the dienol (30 R = Et) as a key intermediate and now they have described two new stereospecific routes to this compound (Scheme 2). In the first synthesis the lactone (27) was converted into the hydroxy-olefin (28) by hydrolysis, esterification, tosylation, and lithium... 

The involvement of monoterpenoids in the juvenile hormone synthesis pathway and the role of juvenile hormone in mating and vitellogenesis support the reproductive impact of these terpenoids on insects. 

Rearrangements of cyclopropanes. Cyclopropanes are interesting not only by themselves, but also because they are easily converted into important synthons in organic chemistry. Recently, rearrangements of cyclopropanes have appeared in the synthesis of, namely, steroids (pregn-4-en-one) [58], 19-norsteroids (estrone, 19-norandrost-4-en-3-17-dione, estradiol-17,8)and 19-nortestosterone [59], insect juvenile hormone analogs [60]. 

This does not mean that dried-droplet preparations cannot be imaged. Indeed, clearly dependent on the chemical structure, certain compounds do remain in the tissue (e.g., the (prenol) lipid ion at 610.444). For specific analyte molecules such as these latter compounds, the dried-droplet method can thus be used as a specific sample preparation method to wash away unwanted compounds. In this respect, it is interesting to note that the corpora cardiaca are the main synthesis sites of the insect juvenile hormone (JH), also a prenol lipid of the class of terpenoids. JH as such is not secreted in the adult stage of the insect imaged here, but the presence of other terpenoids in this tissue is expected. 

Faulkner, D. J. Petersen, M. R. Application of the Claisen Rearrangement to the Synthesis of Trans Trisubstituted Olefinic Bonds. Synthesis of Squalene and Insect Juvenile Hormone J. Am. Chem. Soc. 1973, 95, 553. 

Archelas, A., Delbecque, J.R and Furstoss, R. (1993) Microbiological transformations. 30. Enantioselective hydrolysis of racemic epoxides the synthesis of enantiopure insect juvenile hormone analogs (Bower s compound). Tetrahedron Asymmetry, 4,2445-2446. 

The hydroxy ketones 5 and 6 [35] were the key building blocks in the synthesis of enantiomerically pure insect juvenile hormones [27,35] as shown in Fig. 6. In the case of the synthesis of (+)-4-methyl juvenile hormone I, the half ester 7 was also employed as the building block [36]. 

Another aspect of the sex pheromone communication system concerns the endogenous signals that control pheromone production and release from the emitting insect. A number of hormones have been found to be involved in the control of pheromone production in various insect species (18). Juvenile hormone was found to induce vitellogenesis and sex pheromone production in some cockroach and beetle species. However, ecdysteroids were found to be involved in regulating reproductive processes, including vitellogenin synthesis, in dipteran species. 

One of the insect neurohormones, the activation hormone, controls the secretion of the corpora allata, paired glands that synthesize the juvenile hormone (Fig. 22-4) in insect larvae. While the structure of the juvenile hormone varies somewhat with species, it is usually a polyprenyl ester. A specific binding protein provides the hormone with protection from degrada-tive enzymes. However, in the tobacco homworm an esterase, able to hydrolyze the protein-bound juvenile hormone, is produced at the start of pupal differentiation.354 The exact mechanism of action of juvenile hormones has been difficult to determine. However, it affects polyamine synthesis.355 356... 

Another common mechanism for modulating hormonal response involves two (or more) hormonal inputs with both positive and negative effects (see fig. 24.21). The hypothalamic peptides, somatostatin and GRF, have opposite effects on GH synthesis and secretion. Similarly, glucagon and insulin have opposite effects on gluconeogenesis in the liver (see the discussion earlier in this chapter), and some of the effects of ecdysone on gene expression in insects are blocked by juvenile hormone (a terpene derivative fig. 24.22). 

Feyereisen R. (1985) Regulation of juvenile hormone titer synthesis. In Comprehensive Insect Physiology Biochemistry and Pharmacology, eds G. A. Kerkut and L. I. Gilbert pp. 391 —429. Pergamon Press, Oxford. 

---