Juvenile hormones

Farnesol derivatives also have juvenile hormone activity.  [c.172]

Insect juvenile hormone Insect repellents Insect resistance Insects  [c.515]

L. 1. Gilbert, ed.. The Juvenile Hormones, Plenum Press, New York, 1976.  [c.310]

Insect Juvenile Hormones and Farnesol.146  [c.145]

Stereospecific Synthesis of Trisubstituted Olefins from Acetylenes or Aldehydes Applications to the Total Synthesis of Cecropia Juvenile Hormones (JH) and Farnesol  [c.146]

The determination of the structure of the insect juvenile hormone of Cecropia (now called JH-I) (Ang. Chem. Int., 1967, 6, 179) posed a challenge to synthesis because no methods then existed for the stereospecific synthesis of the type of trisubstituted olefinic linkages contained in JH-I. The first stereospecific synthesis, outlined below, depended on a number of new synthetic methods which now find general use. The synthesis of trisubstituted olefins from acetylenes by overall carbometallation can now be effected by a variety of reagents involving metals such as copper, titanium, zirconium, palladium, and nickel. Although JH-I is not a practical agent for insect control, the availability of synthetic material paved the way for the understanding of its action and the development of useful analogs.  [c.146]

Juvenile Hormone (JH-1) Trost, JACS, 1967,89, 5292.  [c.362]

It was agreed at the workshop that endocrine disrupting activity could only be adequately defined in terms of effects in intact animals, be they juvenile or adult, or in the offspring of exposed parents. For many chemicals, evidence of endocrine disrupting activity has been obtained only by the use of in vitro models, such as hormone binding assays. It was accepted, therefore, that chemicals active in such models should be considered only as potential EDs and should be distinguished from those established as active in vivo. For such chemicals, an alternative definition was recommended  [c.4]

Some copper reagents bearing large alkyl groups also show pronounced stereoselectivity, when they react with dihalides. The halogen on the sterically more hindered side of a molecule is substituted much more slowly. An example is the conversion of a gem-dichloride into a chiral dialkyl compound as part of a synthetic sequence for sirenin (K. Kitatani, 1976). Substitution of a vinylic halide was used in the synthesis of juvenile hormones (E.J. Corey, I968B). Michael type alkylations of activated C = C bonds are also possible with copper or-ganyl anions. These reactions are regioselective, because the copper tends to form it-complexes with C=C bonds rather than o-complexes with carbonyl groups (W.C. Still, 1976). They occur also stereoselective at the least hindered side of cyclic systems (G.H. Posner, 1972).  [c.20]

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).  [c.382]

A wide variety of broad-spectmm agricultural iasecticides have beea iavestigated for their suitabiHty for iasectproofiag. Other chemicals iavestigated have iacluded juvenile hormones, compounds, anionic surfactants, organotin compounds, eg, triphenyl tin chloride and acetate, thioureas, and 2-thienylethylene (127,128). Some of these have shown activity against wool-eating insects, but all, with the exception of certain synthetic pyrethroids, have disadvantages that have precluded their commercial dyebath use. Certain quaternary ammonium detergents have found specialized use for protection of wool insulation, where they provide a combined rot-resist and iasect-resist action. Because of their ionic character, they are not lost from the wool by volatilization when appHed by spraying (123).  [c.350]

A review of possible correlations between environmental toxicants and declines in global amphibian populations" " found several potential mechanisms other than lethal toxicity, including increased susceptibility to disease, impairment of predator avoidance, retardation of growth and development, and reproductive impairment. However, the authors concluded that the few studies available did not identify the causes of the population declines. Thus, the amphibian population declines, in particular among anuran species, might conceivably be related to many factors, including exposure to increasing levels of UV light, disappearance of natural habitat, parasitism, disease and endocrine disruption. Both parasitism by trematode (flatworm) and exposure to chemicals have been linked to the appearance of gross malformations in the United States and Canada." The majority of these malformations are fatal prior to sexual maturity and are therefore only apparent in tadpoles and juveniles. In Japan, research has linked these malformations with high levels of PCBs and organochlorine pesticides," and high concentrations of PCBs have been associated with the population decline of green frogs in southern Ontario." American research has singled out a group of insecticides which contain S-methoprene (a juvenile hormone mimic used in the control of mosquitoes) as the major active ingredient. This compound is known to undergo degradation by UV light to form isomers of retinol, a well-documented teratogen.  [c.72]

Unsymmetrical trans vinyl halides have been prepared from acetylenic alcohols by Corey and co-workers (as illustrated in the accompanying formulation) in connection with their synthesis of farnesol and Gecropia juvenile hormone. Several syntheses of vinyl halides (with  [c.29]

This remarkable process allows the joining of three components in one synthetic step. This methodology was applied to the syntheses of several juvenile hormones and famesol.  [c.149]

Substances in sewage and industrial effluent have been shown to cause a number of changes in fish, including intersex, production in adult males and juvenile forms of the female yolk precursor lipoprotein vitellogenin, and abnormal testicular development. A combination of laboratory and field studies, mainly on rainbow trout and roach, have suggested that the effects, in the UK, are caused by oestrogenic hormones from human waste and also by alkylphenols. " "" Most of the work to date on oestrogenic effects of sewage on fish has been conducted on freshwater species, although laboratory and field experiments have shown vitellogenin induction in the males of a number of estuarine and marine  [c.10]

See pages that mention the term Juvenile hormones : [c.148]    [c.229]    [c.537]    [c.538]    [c.538]    [c.172]    [c.293]    [c.183]    [c.693]    [c.887]    [c.54]    [c.55]    [c.56]    [c.96]    [c.147]    [c.62]   
The logic of chemical synthesis (1989) -- [ c.146 , c.147 , c.148 , c.149 , c.362 ]