Cf-Limonene

FIGURE 10.16 Schematic diagram of the eight OH-cf-limonene adduct isomers. 

The other constituent of dill oil is cf-limonene, identical with that from lemon oil. Phellandrene is present in Spanish dill oil, but the samples examined were obtained from the whole herb. Small quantities are present in the German oil, but the nitrite reaction only gave positive results when applied to the lower fractions. It has been suggested that it is also present in English oil, and that its presence, in this case again, is due to the use of the whole herb. Phellandrene, however, is not an invariable constituent of English oil, although possibly present in the oil from imperfectly ripened fruit. 

Vapor-exposure assays for adult cat fleas also showed that cf-limonene was effective at inducing rapid knockdown and mortality as a fumigant (5). The larvae were also relatively susceptible to cf-limonene vapors, while the eggs were less susceptible and pupae were relatively tolerant of this chemical. 

Fig 3 - Effects of cf-limonene concentration and exposure duration on relative conduction velocity in MGF (reproduced from 11 by permission, copyright Academic Press, 1990) ... 

Limonene, one of the most prominent natural monoterpenes (cf Section VII), represents a particular derivative of 4-vinylcyclohexene since it has been studied with respect to the pronounced energy dependence of its fragmentation behaviour (Scheme 7). Counterintuitively, and in contrast to 4-vinylcyclohexene, the radical cations of limonene (27) do not undergo the retro-Diels-Alder reaction if the internal energy of the ions is low. As... 

Acylation of limonene at the disubstituted double bond is favoured by a factor of 2.3 over reaction at the trisubstituted double bond using acetyl hexachloroan-timonate. Mixed alkylcuprate alkylation of tricarbonylcyclohexadienyliron salts has been used to synthesize the a-phellandrene tricarbonyliron complex. Dichlorocarbene addition to limonene in the presence of 1,4-diazabicy-clo[2,2,2]octane is almost 100% stereoselective at the trisubstituted double bond (no yield given) (cf. Vol. 6, p. 31) in contrast to dibromocarbene addition to carvone (Vol. 7, p. 34), dichlorocarbene addition to the carveols is not regio-specific. ... 

Other papers related to p-menthanes concern vinylaziridine formation from pulegone oxime and from carvone-NN-dimethylhydrazone methiodate,234 non-ozonolytic cleavage of 10-trichloromethyl-limonene,235 and the stereochemistry of 1-chloro-l-nitroso-p-menthanes236 and of dihydropinol rearrangements (cf. Vol. 2, p. 34).237... 

Photoreaction on (-i-) limonene (orange oil) produces mixed isomers, first couple of fractions canbe used to create active CBl agonists see Schenck 1964. cfs-p-Menth-2-ene-l,8,-diol and mixed isomers from a culture of Penicillium italicum andP digitatum (moldy oranges) see Bowen (1975). 

Bardyshev reports the salicylic acid-catalysed rearrangement of isoterpinolene to various p-methadienes (cf. Vol. 3, p. 71, ref. 314). Lewis acid-catalysed rearrangement of methyl perillate is reported in an investigation of the acylation of the exocyclic double bond. " Pyrolysis of limonene diacetate yields perillyl acetate as the major product. ... 

Figure 2. Structures of terpenoids chemically formed from linalool (1 ) at pH 3.5 (cf. Fig.1-4). (2) 2,4(8)-p-menthadiene (3) B-myrcene (4) a-phellandrene (5) cx-terpinene (6) limonene (7) B-phellandrene (8) (Z)-ocimene (9) y-terpinene (10) (E)-ocimene (11) p-cymene (12) terpinolene (13) (E,Z)-alloocimene (14) (E,E)-alloocimene (15) a-terpineol (16) 3,7-dimethyl-l-oct-ene-3,7-diol (17) 1,8-cineole (18) 2,2,6-trimethyl-2-vinyl-te-trahydropyran.

Dienes may be transformed into alkenes by partial hydroalumination followed by hydrolysis. The reactions occur particularly unambiguously and often with almost quantitative yields if the dienes contain certain types of C=C double bond (see Section V,B,3) [e.g., 4-vinylcyclohexene — 4-ethylcyclohexene limonene —> l-methyl-4-isopropylcyclohexene 296) 2,6-dimethyl-2,7-octadiene — 2,6-dimethyl-2-octene 227). Cis hydroalumination of alkynes having G=C triple bonds in the middle of the chain leads via the corresponding alkenyl alanes to 1,2-cfs-disubstituted ethylenes 252). 

CfS isomer trans-isomer exo isomer Scheme 5.9 Photosensitized addition of methanol to (R)-(t)-(z)-limonene. 

Fig. 16.11 Some components of termite defense secretions (7) Germacrene A, (2) p-farnesene, (5) geranyllinalool, (4) y-cadinene, (5) y-cadinene aldehyde, (5) cubitene, (7) biflora-4,10,(19), 15-triene, (8) cembrene A, (P) 3-Z-cembrene A, (10) cis- -ocimene, (11) 4,ll-epoxy-c/5 -eudesmane, (12) lO-epi-eudesma-3,11-diene, (13) 8-epi-cararrapi oxide, (14) cararrapi oxide, (15) cis-P-ocimene, (16) Germacrene A, (17) aristolochene, (18) epi-a-selenene, (19,20) macrocyclic lactones, (21) myrcene, (22) a-pinene, (25)/3-pinene, (24) limonene, (25) camphene, (26) a trinervitene, (27) a kempene, (28) a secotrinervitene, (29) a rippertane, (30) ancistrofuran, (57) a-cyclogeraniolene, (52) -cyclogeraniolene, (55) ancistrodial (cf. Fig. 16.8 see text for references).

Rate constants for gas-phase ozonation of keto-limonene and the mechanism of the reaction have been, respectively, calculated and investigated using transition state theory at the CCSD(T)/6-31G(d) -l- CF//B3LYP/6-31G(d,p) level and ab initio methods. Two different possibilities for ozonation of the double bond are considered and the corresponding van der Waals complexes are found for 1-endo and 2-endo variants. ... 

Terpin n Terpinol, 4-Hydroxy-oc,a,4-trimethylcyclohexa-nemethanol. Additional Names p-menthane-l,8-diol dipenteneglycol. Molecular Formula C10H20O2. Molecular Weight 172.26. Percent Composition C 69.72%, H 11.70%, O 18.58%. Literature references from Merck index (2001) 13th edn. Both ds-and frans-modifica-tions are known. The ds-compd is obtained most readily in the hydrated form, cfs-terpin hydrate. Prepn of ds-form from oil of turpentine Hempel (1876) Ann 180 71 Wallach (1885) Ann 230 225 Schmitt (1955) Mfg Chemist (1955) 26 350. From d-limonene Sword (1925) J Chem Soc (1925) 127 1632. Prepn of trans-form from 1,8-cineole, a-terpineol or ds-terpin hydrate Matsuura et al (1958) Bull Chem Soc Japan 31 990 Lombard R, Ambroise G (1961) Bull Soc Chim France 230. Structure of ds- and trans-forms Baeyer Ber (1893) 26 2861. 

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