Farnesene structure

Alpha farnesene, structure of, 207 Alpha helix (protein), 1038 Alpha-keratin, molecular model of, 1039... 

CS115 Nobumoto, Y., K. Kubota, A. Koba-yashi and T. Yamanishi. Structure of alpha-farnesen in the essential oil of CS126 oolong tea. Agr Biol Chem 1990 ... 

Farnesene 69 is a constituent of hops oil and many other oils. a-Farnesene 70 is the structural isomer. Structural representations of a-farnesene and -farne-sene are illustrated in Structure 4.17. 

The structural similarities between the putative mammalian chemosignals and the pheromones identified previously in the insect world are quite striking. The farnesenes [257, 258] (entries 66, 67) and 2-heptanone [259] (entry 68) have been implicated previously as insect pheromones. There is only one double bond distinguishing the male mouse pheromone 3,4-dehydro-exo-brevicomin (entry 65) from a bark beetle pheromone [260], brevicomin. In addition, the elephant pheromone (Z)-7-dodecen-l-yl acetate (entry 69) is also known to be an insect pheromone [259]. While the potency may not compare to the insect system, investigators are beginning to find evidence that many mammals ranging from pigs to elephants can have a pheromone-type response to a sniff of secretions even humans appear to respond [261],... 

Se8qulterpenold semlochemlcals. The aphid-repellent effect of Type B trichomes of S. berthaultii (25) appears to be due to the presence of sesquiterpenes (22). Three major components, identified by GC-MS, were B-caryophyllene, B -cubebene and A-cadinene. E-B-farnesene was also identified, but was a minor component. GC-MS of the other major components in Type B trichome exudate indicated sesquiterpenold structures, but these have not been identified. 

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. 

Farnesene (below) is a compound found in the waxy coating of apples, (a) Give the structure and lUPAC name of the product formed when farnesene is allowed to react with excess hydrogen in the presence of a platinum catalyst, (b) How many stereoisomers of the product are possible ... 

Fig. 6.7 A case of moonlighting. The S. coelicolor CYP170A1 converts epi-isozizaene via albaflavenol intermediate(s) to the sesquiterpene single ketone antibiotic albaflavenone by two successive allylic oxidations (a) [202], A secondary terpenoid synthase role was also discovered to produce farnesene (b) [849]. The structure...

Bowers, W. S., Nishino, C., Montgomery, M. E. and Nault, L. R. (1977a) Structure-activity relationships of analogs of the aphid alarm pheromone, ( )-p-farnesene. J, Insect Physiol, 23, 697-701. 

Traw -P-farnesene (400) is frequently found in the Jungermanniales. Recently, three unique monocyclofarnesenes, tentatively named Ps-1 (401), Ps-2 (402) and Ps-2 (403) were isolated from Ptychanthus striatus structures were established using spectral evidence (324). It is interesting... 

The number of sesquiterpenes is high (over 150 compounds). There are compounds with aliphatic (farnesenes), monocyclic (humulenes, bisabolenes, elem-enes), bicyclic (cadinenes, muurolenes, selinenes, caryophyllenes, germacrenes), tricyclic (copaenes, ylangenes, longifolenes.longicyclenes), and tetracyclic (sati-vene) structures. 

Several aphid apecies of economic importance use ( )-P-farnesene as an alarm pheromone 304—307). Bowers et al. 308) have studied the activity of various famesene and nor-famesene analogs in an attempt to define the structural requirements necessary for alarm activity. They concluded that the following properties were important 1) there should be an JE -configurational double bond in the central position of the molecule, 2) the double bond in the terminal isoprene unit acts as an activator, 3) a rt-bond of 1.34 to 1.39 A must be located ten carbon... 

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