Cecropia Moth Juvenile hormone

A typical example of an application of ozonolysis in synthesis is the cleavage of the alkene unit in 351 to give aldehyde 352, with loss of formaldehyde, a part of Smith s synthesis of (+)-thiazinotrienomycin In this case, the reductive workup used triphenylphosphine. Ozonolysis of 353 gave aldehyde 354, an intermediate in Corey s synthesis of the Cecropia Moth Juvenile hormone, via a reductive workup with DMS. Note that the electron rich vinyl ether moiety reacted in preference to the simple alkene moiety. The ozonolysis product of the methyl vinyl ether was a methyl ester. This method is particularly useful for the preparation of protected acids. In general, electron rich alkenes are oxidized faster than electron-poor alkenes. 

Ozonolysis of an enol ether provides a carboxylic ester, as one of the two carbonyl products. For example, the enol ether 103 (formed by Birch reduction - see Section 7.2) was converted to the ester-alcohol 104, used in a synthesis of the Cecropia moth juvenile hormone (5.103). This example illustrates the preferential oxidation of the more electron-rich alkene by the electrophilic ozone. 

As early as 1934 Wigglesworth showed that the evolutionary differentiation of insects is regulated by a centre in the brain. In 1956 Williams obtained from Cecropia moth a highly active extract which produced anomalies in the metamorphosis of experimental insects. Following this first description of the action of juvenile hormone, Gilbert and Schneiderman (1958), then Williams et al. (1959) described the juvenile hormone action of lipid extracts obtained from different mammalian organs. The pure active substance was isolated first by Schmialek (1961) from feces of the yellow mealworm, Tenebrio Molitor, and identified as famesol (1), known as an intermediate product in steroid biosynthesis. Six years later, Roeller and co-workers (1967) elucidated the structure of the juvenile hormone isolated from the male of Cecropia. The hormone was ascribed the structure methyl ( , )-3,11-dimethyl-10,ll-epoxy-7-ethyl-2,6-tridecadienoate (2), and was called C,g-JH. Independent of these workers, Meyer et al. (1968) isolated also from Cecropia another juvenile hormone, ( , )-10,11-epoxy farnesenate (3), called C,g-JH. 

A number of compounds important to animal physiology have been identified as isoprenoid compounds. Notable examples are vitamin A, retinal (Section 28-7), and squalene (Table 30-1). Also, terpene hydrocarbons and oxygenated terpenes have been isolated from insects and, like famesol, show hormonal and pheromonal activity. As one example, the juvenile hormone isolated from Cecropia silk moths has the structure shown in 3 ... 

C. M. Williams ( 1) prepared the first active extract from the cecropia moth and showed that this extract prevented adult development when applied to insect pupae. Treated pupae molted into morphogenetic monsters and died. Treatment of other stages produced no ill effects. From these studies it became clear that during the transformation of the immature insect into the adult (during the pupal stage) the juvenile hormones must be absent. This short developmental period is completely deranged when supplied with JH. 

Phvtoluvenolds. Wigglesworth (JL) demonstrated that a hormone secreted by the insect corpora allata was responsible for the control of differentiation in immature insects and reproduction in adult female insects. Williams (3) prepared an active extract of this hormone from adult male cecropia moths and called it "juvenile hormone". We were able to derive sufficient knowledge of the chemistry of the juvenile hormone from the study of the active cecropia extract to synthesize JH III Q). Seven years later its presence as a natural hormone in the tobacco hornworm was confirmed Ci). Three other analogous juvenile hormones (JH 0, I, II) have been found to occur only in lepidoptera (5, ., 2.) (Figure 1). Juvenile hormone III is the principal juvenile hormone of insects and has been demonstrated in all of the insect taxa investigated. 

The structure of the juvenile hormone of the moth Hyalophora cecropia was confirmed by the following synthesis. (At each stage where geometric isomers were obtained, these were separated and the desired one—(Z) or ( )—was selected on the basis of its nmr spectrum.)... 

Another example of a sesquiterpene-derived insect juvenile hormone is that of the giant silkworm moth, Hyalophora cecropia (Fig. 21.18). Several juvenile hormone mimics have been found in plants (Bowers, 1985,1991,1992 Fraga, 1991 Menn and Beroza, 1972). 

Juvenile hormone, larval hormone, stalus-quo hormone insect hormone responsible for the control of molting. The first J.h. to be isolated and structurally elucidated was obtained from the abdomens of the male silk worm moth (Hyalophora cecropia) in 200 ig quantities. Homologs of this compound were discovered later, and other J.h. were postulated. Juva-bione (see) and famesol derivatives are among the... 

In many insects, for example in the large silk moth Hyalophora cecropia, a large amount of the juvenile hormone is stored. In most species it is inactive, or is so bound that it is no longer extractable. In Tenebrio, excretion in the faeces heis been observed" , the substance being identified as famesol. 

Juvenile hormone (JH) is a substance that controls metamorphosis in insects. It is produced by the male wild silk moth, Hyalophora cecropia L., and its presence delays the maturation of insect larvae until the appropriate... 

The biosynthesis of the insect juvenile hormone (19) continues to present incorporation problems. The acid 10-epoxy-7-ethyl-3,ll-dimethyltrideca-2,6-dienoic acid (20) acts as a substrate for the hormone in the giant silk moth, Hyalopkora cecropia. L-Methionine gave the ester methyl group. However, it did not contribute to the carbon skeleton whilst farnesol, farnesol pyrophosphate, propionate, and mevalonate were apparently not utilized for the biosynthesis of the hormone under the conditions of these experiments. There was a very low incorporation of [2- C]acetate into juvenile hormone. 

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