Carvone removal

Figure 10.12 Room temperature CD spectra of SPS films spin-coated at 1600rpm from 0.25 wt% chloroform solution onto quartz surface after exposure to vapors of R (thick lines) or S-carvone (dashed lines) after complete carvone removal by supercritical carbon dioxide (blue/middle [at about 198nm] lines) followed by thermal treatments at 160 °C and 240 °C, leading to crystal-to-crystal transition between helical crystalline phases (5 —> y, green/inner fines) or from helical toward trans-planar crystalline phase (y a, red/outer fines).

A 500-mL, three-necked, round-bottomed flask is equipped with a 25-mL pressure-equalizing dropping funnel, a mechanical stirrer, and a Claisen adapter fitted with a nitrogen inlet adapter and a low temperature thermometer (Note 1). The flask is charged with 11.5 g (0.077 mol) of (R)-(-)-carvone (Note 2), 10.8 g (0.079 mol) of 1-methyl-l-(trimethylsilyl )allene (Note 3), and 180 mL of dry dichloromethane (Note 4), and then cooled below -75°C with a dry ice-acetone bath while a solution of 17.4 g (0.092 mol) of titanium tetrachloride (Note 5) in 10 ml of dichloromethane is added dropwise over 1 hr. After 30 min, the cold bath is removed, and the reaction mixture, which appears as a red suspension, is allowed to warm to 0°C over approximately 30 min. The resulting dark red solution is poured slowly into a 2-L Erlenmeyer flask containing a magnetically-stirred mixture of 400 mL of diethyl ether and 400 mL of water (Note 6). The aqueous phase is separated and extracted with... 

TERPENELESS OIL. An essential oil from which the teqoene components have been removed by extraction and fractionation, either alone or in combination. The optical activity of the oil is thus reduced. The terpene-less grades are much more highly concentrated than the original oil (15—30 times). Removal of terpenes is necessary to inhibit spoilage, particularly of oils derived from citrus sources. O11 atmospheric oxidation the specific terpenes form compounds that impair the value of the oil for example, d-limonene oxidazes to carvone and y-terpinene to p-cymene. Terpeneless grades of citrus oils are commercially available. 

Ionene, a commercial fragrance, has been prepared traditionally by treatment of a- and /3-iononcs with hydriodic acid containing phosphorus or by distillative heating in the presence of 0.5% iodine. In an unoptimized demonstration, cyclization occurred more cleanly and simply by MBR with /3-ionone in water at 250 °C (Scheme 19) [83]. Work-up also was facilitated, as the need for removal of catalyst or the formation and separation of bi-products was avoided. At elevated temperature, the addition of water to olefins can occur readily, without adding catalyst. (S)-(+)-carvone in water for 10 min at 180 °C afforded optically pure 8-hydroxy-p-6-mcnlhcn-2-one as an intermediate toward carvacrol [84], Addition of water across the 8,9-double bond of carvone occurred regioselectively, by Markovnikov addition. Carvacrol itself was obtained almost quantitatively from carvone at 250 °C after 10 min (Scheme 19) [84]. 

Enones. Two groups have reported the oxidation of silyl enol ethers to o,/3-unsaturated ketones using DDQ. This method is most suitable for cyclohexanone derivatives. Fleming and Paterson report that yields are generally improved by addition of collidine (1.5 equiv.), which presumably removes the by-product DDQHj. This last communication also reports improvements in the preparation of either the kinetic or thermodynamic silyl enol ethers by House s method (3, 310-311). By a combination of the two reactions, carvone (6) can be prepared from 2-methylcyclohexanone (1) in an overall yield of 28% (equation I). 

In other instances, the parameters that determine pollination are complex. Many of these orchids attract only the male bee. When a flower is placed in an opaque container, the bees still find it, indicating that the bees use odor and not vision to locate the flowers. Even when the flower was removed, the bees continued to be attracted to the container. Most of the orchid species produce a combination of 7-10 compounds. Among these are fi -carvone (48), 1,8-cineole (10), eugenol, bomyl acetate (77), anethole, geraniol (4), methyl cinnamate, methyl salicylate, myrcene (17), vanillin, and indole. In pure form, 1,8-cineole, methyl salicylate, eugenol, methyl cinnamate, bomyl acetate, a-phellandrene (79), myrcene (17), piperonal, indole, vanillin, and benzyl acetate serve as attractants. Neither a- or P-pinene nor oci-mene (47) are attractive to the bees tested. Combinations of these compounds (in proportions similar to those found in various orchid species) lead to greater specificity of attraction. For example, when a-pinene (14) is added to a mixture of 1,8-cineole (10) and benzyl acetate in the proportions found in the orchid Stanhopea tricornis, fewer bees of two species are attracted than when a mixture of only 1,8-cineole... 

Inject 50 fxL of caraway or spearmint oil on the gas-chromatography column. Just before a component of the oil (limonene or carvone) elutes from the column, install a gas-collection tube at the exit port, as described in Technique 22, Section 22.11. To determine when to connect the gas-collection tube, refer to the chromatograms prepared by your instructor. These chromatograms have been run on the same instrument you are using under the same conditions. Ideally, you should connect the gas-collection tube just before the limonene or carvone elutes from the column and remove the tube as soon as all the component has been collected but before any other compound begins to elute from the column. You can accomplish this most easily by watching the recorder as your sample passes through the column. The collection tube is connected (if possible) just before a peak is produced or as soon as a deflection is observed. When the pen returns to the baseline, remove the gas collection tube. 

A solution of sulfonyl chloride (3) (0.22 g, 1.0 mmol) and (—)-carvone (5) (0.09 g, 0.6 mmol MeCN, 2.0 mL) is added to a heterogeneous solution of KO2 (0.222 g 3.0 mmol, MeCN, 1.0 mL) at —35 °C under dry argon atmosphere. After stirring at —35 °C for 4 h, the reaction mixture is concentrated and then extracted with CHCI3. The residue obtained after removal of solvent is purified by preparative TLC to furnish (6) in 83% yield. Epoxidation of ds-stilbene (7) by reaction with the intermediate (1) furnishes a 70 30 mixture of oxides (8) and (9) this reaction suggests that the reactive intermediate is a radical. ... 

The most familiar ketone is acetone, tire main component of fingernail-polish remover. Many ketones also have pleasant aromas. For example, 2-heptanone is responsible for the smell of cloves, carvone for the smell of spearmint, and ionone for the smell of raspberries. 

Elze, after removing the carvone from a German spearmint oil, obtained an oil with a more intense spearmint odour than the original oil. It had a specific gravity 0 917 and optical rotation - 28. It contained 18 per cent, of esters and on fractionation yielded the follow-in g results —... 

France were found to be anosmic or severely hyposmic. Only one subject in Sweden was suspected of a specific anosmia to R-( + )-carvone [14]. The scores of all these subjects were removed before data analysis. 

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