Farnesol and Zingiberene

/Farnesol/HOOcc currence - farnesal is Present in manyessential oils such as citronella,nerali, lemon grass rose and balsamIt is used in perfumery to emphasize the odoursof sweet floral perfumes.farnesol and its derivatives are imp. startingcompound for both natural and artificialorganic synthesis.Structure Determination of farnesalElemental analysis shows that MF of farnesol=C15H260Farnesol belongs to sesquiterpenoid class ofterpenoidsIt contains three isoprene units joined headto tailDBE=x+12 16-13 = 03 (Cx HyHz)C15H320Analysis of Unsaturation-C15 H260Hydrogenation experiment.3H2C15H260H2C15 H320farnesol cat. hexahydrofarenesolIC15H32 CnHantz(farnesol contains threeacyclic str Jdouble bonds) Absorption maximum: Uv max: 192- 196 nm(E 28,500)Three double bonds are not conjugatedNatureofoxygen-whenfarneselisoxidizedwith chromic acid, farnesalC15H240isobtainedIIbehaves as an aldehyde5H260(403C15 H240farnesolfarnesalIIIConclusion: farnesol is a Pri- alcoholG1422CH2OHG14H23 CHODBE =3 MF C15H260Three double bondPri alcoholIn 1913C14H23CH2OH CrU3CluH23 CHOfarnesolfarnesal(ii) AGOIIIC14H23 CNC15H260C15H240cyanidecompounddihydroC13 H22 OIIIVhandscetone found to begeranye acetone(i) KOH(ii) H+G4H23CO2H &farnesenic Cro3HOIC15 5H260IIfarnesolC15H240(farnesal)NH2OH2AGOCO2H18KOHIVH+95H2402(farnesenic acid)NIIIMajor clue93H220geranyl acetoneVOzonolysis of farnesol- - (1913)Vof0H(i) O3++(ii) MegsHHOHOE0glycofarnesalLaevuldehydealdehyde Synthesis of farnesol - (1923)10EtoNaEto+Eto0Ethyl acetoacetateGerange chlorideHydroBa(OH)2lyst11) He(1)NaNH2o(2) H(ECH(3) H2OOHgeranyl acetonenerolidolallylicHtmentHOfarnesolP.T.O coveyetal19672PCL5cl0lutidinece11G3H22U2 ]Ageranyl acetonedoubleNaNH2 /liq NH3EliminationHCHONaHOBC13H19NaC C14H22OOLAH/All31I2Me2CuLiIHOHO[ C14H23IO JE C15H260D(farnesol)LAH/AIU3kI2I10HO CyMoreLIAIHY-H2IfHHOHAioMHAloH.7AlHHHHAlI2GH0IHHOStereo isomerism in farnesoltrans-trans farnesolOHHHHHcis-cisfarnesolOH Hcis trans farnesolHOHtrans-cisHHtarnesolOHProblems1. complete the following reach sequenceNH4OHH260(r03C15H240C15H25NOAC2OfarnesalA13C13H220C15H24O2(1)KorC15H23N+ED(ij)H+c2. write the Products of the treatment of farnesalwith each of the followings.1)AC2O2)H2/Pt3) O3 / Me2S 4)(r035) Productof4and NHgOH6 Product of5and A620 Zingiberene G5 H24occurrence and UsesZingiberene is Present in ginger that gives it adistinct flavouringIt is used in cosmetics and fragrances.Antiviral antiulcer and antifertility effectsIt is optically active and exist in (-) formin ginger.Str. Determination of ZingibereneElemental analysis shows that MF of Zingiberene=C15 H24Zingiberene belongs to sesquiterpene class ofterpenesIt contains three isoprene units joined headto tail.DBE = x + 1 - - y/2 = 16-12 =04(Double BondEquivalence) (Degree of unsaturation )ORDBE = 04Analysis for the nature of Double Bond1. Zingiberene adds to three molecules of H2.3.It is reduced by NalEtOH to form dihydro-zingiberene C15H26.3. It forms dihydrochlori derivative with HCl.C15H30 / 'CHH2n]N9C15H241913C15H26C15H24H2C15H303H2dihydro EtOH Zingiberene Pt HexahydroZingiberene2HaZingibereneDihydrochloridederivative Conclusions:Zingiberene contains three double bonds.Two double bonds in Zingiberene are conjugated.chemical arithmetic : C15H30 corresponds toParent HydrocarbonTherefore, zingiberene is monocyclic in NatureInformation:DBE=04Three double bondTwo double bonds are conjugatedMonocyclic in Naturefurther evidences for conjugation:It forms adduct with maleic anhydride.Zingiberene absorbs at Amax = 260 nm (E 2700)Conclusion: Zingiberene is a homoannular dienehomoannularHetero annulardienedienedmax = 253+amax= 214+Information: HomoannulardieroOzonolysis: Proof for carbon skeleton1929C15H240301004++0ZingibereneAcetoneCOOHCOOHDicarboxyliclavalic acidand03i.e zingiberene str. resembleBisabolene925to Bisabolene (2 Bisabolene )(B- Bisabolene) (x: Bisabolene )theconjugated double bondsand homoannulardiene3 PossibilitiesCarbon skeletonof zingiberenesimilar to bisaboleneoxidative degradation of dihydrozingiberere.C15H24Na, NH3C15H26KMn04C12H2005ZingibereneEtoHdihydroketo-ZingiberenedicarboxylicacidInDegradationwithBromoformNaoBrone carbontestDetailsIIIGIH1806tricarboxylic acidNa/EtoHzingiberenekmno4[0](Haloform)NaOBr(O)HCO2HCO2H[0]CO211CO3Hketo dicarb--oxylic acidtri carboxylicacid Position of Conjugation:-Diels Alder reaction of zingiberene1950CO2Me+-cogMeHeatCO2MePyrolysisCO2MeRetro-Diel'sDiel's AlderAlder1,6 dimethylreacnreachOcta-3,6-dieneThis Proff that Zingiberenehas two conjugated double+bond and they arehomo annular.MeO2CCO2Memethyl- 4- methylPhthalateZingiberene is optically active.It contains two chiral centres 3'alcoholSynthesis of Zingiberene-MgbrOH+H3O+THFH3COOCH3G.REthyl acetoacetatep anisylmagnestumBromide-H2ONa/GH504BirchRednH3C.OH+G.RCH3MgBrHOoxalic acid-H2OZingiberine stereochemistry of ZingibereneHence, it exist in four optically isomeric formsThe most common and important isomer is(-) ZingiblrineHenniHHProblems /1. Zingiberene contains three olifinic bonds yetit forms only dihydrochloride instead oftrihydrochloride why ?AN - Zingiberene in the Presence of acid undergoes iso-merisation to give iso zingibereneHtIso ZingibereneIsozingiberene has only two obening bond it reactswith two moles of Hu to give dihydro chlorideof isozingiberene2HUuCH3uCH3Isozingiberene hydrochloride