2,3-Geranyl oxide

The preparation of coenzyme Q usually iavolves either 2,3-dimethoxy-5-methylbenzoquinone or hydroquiaone as the starting material. Treatment of the hydroquiaone with geranyl bromide followed by oxidation affords (61, n = 2) (214). A facile and efficient preparation of ubiquiaone-10 (61, n = 10) has been developed (215). 

The seminal publication [ 12] on the isolation of retigeranic acid proposed a possible biosynthetic pathway by means of cyclization from geranyl famesyl pyrophosphate (12) (Fig. 10.2) to tertiary carbocationic cyclopentane 13. A series of [1, 5] and [1, 2] hydride shifts were proposed to establish the skeletal core of the sesterterpene, whose subsequent oxidation would yield retigeranic acid. 

The precipitate of triphenylphosphine oxide is filtered and washed with 50 ml. of pentane. The solvent is removed from the combined filtrate at the rotary evaporator under water aspirator pressure at room temperature. Distillation of the residue through a 2-cm. Vigreux column attached to a short-path distillation apparatus (Note 4) provides 13.0-14.0 g. (75-81%) of geranyl chloride, b.p. 47-49° (0.4 mm.), w2Sd = 1.4794 (Note 5). 

FIGURE 1.4 Proposed biosynthetic route for the biosynthesis of (A) squalene oxide (squalene-2,3-oxide) via the isoprenoid pathway and (B) triterpene saponins of the dammarane-type and oleanane-type from squalene oxide. PP, diphosphate group GPS, geranyl phosphate synthase FPS, farnesyl phosphate synthase NADPH, nicotinamide adenine dinucleotide phosphate. 

Terpenoid DBPs were investigated by Joll et al. [124] and Qi et al. [125]. The main ozonation product of 2-methylisobomeol was camphor, which was further oxidized to formaldehyde, acetaldehyde, propanal, buntanal, glyoxal, and methyl glyoxal [125]. Chlorination of p-carotene, retinol, p-ionone, and geranyl acetate resulted in the formation of THMs [124]. 

In geranyl, neryl and linalyl acetates the 6,7-double bonds were epoxidised selectively by frani -Ru(0)2(TMP)/2,6-lutidine A-oxide/CgH and also by... 

Oxidation of 1,5-dienes to c -tetiahydrofurandiols was accomplished with RuO /aq. Na(10 )/acetone-EtOAc thus 2,5-dimethyl-1,5-hexadiene gave tetrahydrofurandiol, geranyl acetate yielded cw-tetrahydrofurandiol, and trans, tra 5-2,6-dimethyl-2,6-octadiene-l,8-diol diacetate (1) gave tetrahydrofuran ketol diacetate (2) (Fig. 3.12 cf. mech. Ch. 1) [174],... 

The isoprenoid polyenes famesyl acetate, geranyl acetate and squalene underwent oxidative poly cyclisation to bis-, tris- and penta-tetrahydrofurans with RuO /aq. Na(IO )/CH3CN-EtOAc [185]-[188]. This oxidative polycyclisation of squalene with RuO was shown to lead to the cis-threo-cis-threo-trans-threo-trans-threo-trans penta-tetrahydrofuranyl diol product, this configuration being determined by 2D-NMR (Fig. 3.14) [185]-[188] cf mech. Fig. 1.8 [185]. 

FIGURE 6.28 Oxidation of squalene to 6-methyl-5-hepten-2-one, acetone, geranyl acetone, and 4-oxopentanal (adapted from Fruekilde et al., f998). 

Oxidation of sulfur and phosphorus compounds. The peroxide has been used to oxidize the sulfide (2) to the corresponding sulfone in 83% yield without attack of the double bond. Geranyl phenyl sulfide is oxidized to the corresponding sulfone in Ninular yield.4 Trialkylphosphines and phosphites are oxidized to the corresponding oxides in high yield.5... 

Calandre was created in 1968 to reflect the metallic theme used at that time by Paco Rabanne in his fashion designs. Although it follows the same general pattern as Madame Rochas, both the rose and muguet notes show interesting developments. The use of rose oxide and diphenyl oxide in combination with geranium, nerol, and geranyl acetate as part of the rose complex provides much of the "metallic" character. 

Simple transformations (hydrolysis of the pyrophosphate group to a hydroxy group, elimination, oxidation, etc.) convert geranyl pyrophosphate to monoterpenes such as geraniol, myrcene, and citronellal. 

For this sample the results show identification of 13 major components out of 289, making up 81.25% of the total components. The volatile monoterpene -pinene (peak 1) is the first off the column. The alcohols citronellol (10) and geraniol (11) are responsible for the odour characteristics of geranium, which is lifted and activated by the two rose oxides (2 and 3). The 6,9-guaiadiene (7) is a non-terpene hydrocarbon that acts as a back note but it is not a powerful odour. Component 12 is geranyl butyrate component 13 is epi—eudesmol. Chromatograms and data supplied by Jenny Warden of Traceability. 

Dimethoxy Phenol 3,4-Dimethyl 1,2-Cyclopen tandione 5-Ethyl 3-Hydroxy 4-Methyl 2(5H)-Furanone 3-Ethyl Pyridine Furfuryl Mercaptan Geranyl Isovalerate 2,3 -Heptandione (Z)-3-Hexenyl Butyrate (Z)-3-Hexenyl Formate Hexyl Butyrate Hexyl Hexanoate Isoamyl Isobutyrate Isobutyl Formate Isobutyl Hexanoate Linalool Oxide... 

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