Farnesate

Oxidation of farnesol with chromic acid mixture gives rise to the aldehyde farnesal, which has the following characters —... 

Farnesal forms a semi-carbazone, which crystallises from acetic ether in fine flakes, which melt at 133° to 135°. This body is particularly useful for the identification of farnesol. 

In order to establish the primary character of farnesol, farnesenic acid was prepared from farnesal oxime and the corresponding nitrile. Saponification of the farnesene-nitrile with caustic soda solution yields farnesenic acid and acetic acid, and also a ketone which was identified as a dihydropsewdoionone. The semi-carbazone melts between 95° and 96°. The dihydropmtdoionone from farnesene nitrile proved to be... 

The common names of these intermediates derive from the sources from which they were first isolated. Geraniol, a component of rose oil, has the aroma of geraniums, and farnesol is an aromatic compound found in the flowers of the Farnese acacia tree. Many natural... 

Celentano, A. (2004). In "I vini d ltalia. Giudicati da papa Paolo III (Farnese) e dal suo bottigliere Sante Lancerio", A. Celentano (Ed.), La Conchiglia, Capri, Italy. 

Scheme 26. Asymmetric counteranion-directed catalysis transfer hydrogenation of citral and farnesal...

Stereospecific syntheses of both E) and Z)-o -bisabolenes, (73) and (74) respectively, have been carried out (Scheme 9) and the spectral data for each diastereoisomer have been recorded/ The enantiomers of each have also been made starting from (+)- and (-)-limonene and as a result the j8-bisabolene present in the essential oil of Opoponax has been shown to be the (+)-(5,Z)-isomer, thus correcting a previous report. As might be expected the odour characteristics of the ( )- and (Z)-isomers are subtly different. Both dia-stereoisomeric racemic a-bisabolols (75) and (76) (only one enantiomer of each is shown) have been prepared from the two isoxazolidines (77) and (78) which, in turn, were derived from intramolecular cyclization of the nitrones of (6E)- and (6Z)-farnesal respectivelyFrom this work it is suggested that natural (-)-a-bisabolol must be (75) in contradiction to a recent report which held that (76) is the correct structure of the natural isomer. Further work will be needed to resolve this question. 

NADPH. In a number of examples it has been demonstrated that cyclic sesquiter-penoids result from 2-trans-FFP by dephosphorylation and conversion into 2-cis-farnesol (and hence presumably 2-c/5-FPP) via a redox system. However, in the present case farnesol was not a substrate and no tracer could be demonstrated to be associated with the farnesals. The fact that the added hydrogen came from the opposite face of NADPH to that utilized in common redox systems e.g. liver alcohol dehydrogenase) may indicate that a totally different type of mechanism occurs from that previously proposed for the trans to cis conversion, and the occurrence of a novel cyclopropyl intermediate was suggested (Scheme 12). 

Methyl 4 6-0-ethylidene-2 3-0-oxido-diethylidene- 8-D-glucopyranoside, 4 Methyl ethyl ketone, 450 Methyl irons,irons-farnesate, 227... 

Dioryctria abietivorella oviposits on white pine in response to volatile emissions of myrcene and 3-carene (11.36).166 Terpenes can both deter and stimulate oviposi-tion of the European corn borer. In a series that was screened, the best deterrent was farnesal and the best stimulant a-humulene (11.37).167... 

The condensation of polyhydroxylated benzenes with unsaturated aldehydes including citral or farnesal to provide citrans [Eq. (49)]... 

Komal et (Ref. 53) found gc-ms evidence of the sesquiterpenes 6 sellnene (54), methyl farnesate, farnesyl acetate (55), and farnesol (56) present In an Inhibitory fraction Isolated from water nutgrass (Cyperus serotinus ). This fraction at 300 ppm Inhibited lettuce germination and also Inhibited growth of lettuce and rice seedlings as well as nutgrass Itself. The authors conclude that the sesquiterpenes are responsible for the observed allelopathlc effects. 

Terpenes.- The first total synthesis of the biologically active marine natural product metachromin A (241) has been achieved using an ( )-stereoselective olefination with the phosphonate (240) as the key step. The olefination reaction of the a-cyanophosphonate (242) with ( , )-farnesal (243) has been studied under a wide variety of conditions with a view to optimising (Z)-stereoselectivity.Excellent (Z)-stereoselectivity was achieved and the resulting procedure applied to a stereoselective synthesis of plaunotol (244). Epimerisation and P-elimination of base-sensitive substrates can cause problems in phosphonate- and phosphine oxide-based olefinations. Such reactions have been excluded in a recent report of enantiospecific syntheses of iridoid monoterpene lactones by intramolecular phosphonate-olefination through the use of mild bases such as DBU and di(wopropyl)ethyl amine/lithium chloride. 

CycHzation of methyl farnesate. Reaction of methyl irons,trans-fasiKsa.Vo (1) with NBS and cupric acetate in r-butyl alcohol-HOAc yields the cyclic product (2) in 12% yield. The product was transformed into snyderol (3), a sesquiterpene in Laurencia snyderae. ... 

The continuing search for new marine natural products has led to the discovery of the farnesic acid glycerides (1)—(3) in the nudibranch Archidoris odhneri and the two hydrocarbons (4) and (5) from the gorgonian Plexaurella grisea Kunze. Other new farnesyl/nerolidyl sesquiterpenoids include (6)—(1and the interesting acetal eremoacetal (12) from Eremophila rotundifolia. ... 

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