Menthol, oxidation

Naphthol Antipyrine, camphor, phenol, iron(III) salts, menthol, oxidizing materials, permanganates, urethane... 

Methyl methacrylate 4-Methylnitrobenzene 2- Methylpyridine Methylsodium Molybdenum trioxide Naphthalene 2-Naphthol Air, benzoyl peroxide Sulfuric acid, tetranitromethane Hydrogen peroxide, iron(II) sulfate, sulfuric acid 4-Chloronitrobenzene Chlorine trifluoride, interhalogens, metals Chromium trioxide, dinitrogen pentaoxide Antipyrine, camphor, phenol, iron(III) salts, menthol, oxidizing materials, permanganates, urethane... 

As the electrolyte of a direct methanol fuel cell, acid media is preferable. In alkaline media, carbon dioxide, the final product of menthol oxidation, is adsorbed and accumulated in the electrolyte ... 

Piperitone is of considerable technical im portance. It is a colourless oil of a pleasant peppermint-like smell. (-)-Piperilone has b.p. 109-5-110-5 C/I5mm. Piperitone yields thymol on oxidation with FeCl. On reduction with hydrogen in presence of a nickel catalyst it yields menthone. On reduction with sodium in alcoholic solution all forms of piperitone yield racemic menthols and womenthols together with some racemic a-phel)andrene. 

CO2 reference standard. A special interface, employing the necessary oxidation and reduction reaction chambers and a water separator, was used employed. For standards of 5-nonanone, menthol and (/ )-"y-decalactone, they were able to determine the correct ratios, with relatively little sample preparation. The technical... 

The earlier researches of Charabot have shown that the essential oil of the flowers is richer in menthone than the essential oil of the leaves. And it is in spite of a circulation of menthol, a soluble principle, from the leaf to the inflorescence, that this latter organ contains an essential oil particularly rich in menthone. It must therefore be that the menthol is there converted into menthone by oxidation. 

Beckmann has examined the characters of the optically active men-thones. The oxidation of natural Z-menthol by chromic acid mixture yielded Z-menthone [a]n = - 28 5° which when treated with 90 per cent, sulphuric acid is converted into a d-menthone [ajn = 4- 28 1°, which, however, is not the optical antipode of the first it behaves as a mixture of d- and Z-menthone, but is more strongly dextro-rotatory than it would be if it were only a mixture of the two optical antipodes. 

Chapter 2 to 6 have introduced a variety of reactions such as asymmetric C-C bond formations (Chapters 2, 3, and 5), asymmetric oxidation reactions (Chapter 4), and asymmetric reduction reactions (Chapter 6). Such asymmetric reactions have been applied in several industrial processes, such as the asymmetric synthesis of l-DOPA, a drug for the treatment of Parkinson s disease, via Rh(DIPAMP)-catalyzed hydrogenation (Monsanto) the asymmetric synthesis of the cyclopropane component of cilastatin using a copper complex-catalyzed asymmetric cyclopropanation reaction (Sumitomo) and the industrial synthesis of menthol and citronellal through asymmetric isomerization of enamines and asymmetric hydrogenation reactions (Takasago). Now, the side chain of taxol can also be synthesized by several asymmetric approaches. 

Mesitylene, production from acetone, 1 164 Mesityl oxide, 14 589-590 characteristics of, 16 337 hydrogenation, 16 337-338 hydrogen peroxide treatment of, 16 338 Z-menthol from, 24 520 production of, 16 336-337 production from acetone, 1 164, 174 Mesogenic diols, 25 460 Mesogenic molecules, solids of, 15 82 Mesogens, 24 53, 54 Mesomixing, 16 683 Mesomorphic behavior, 24 53-54 Mesomorphic phase transitions, 15 102 Mesomorphism, 15 81. See also Liquid crystalline materials Mesophase pitch-based carbon fiber, 26 734-735... 

In 1990, Choudary [139] reported that titanium-pillared montmorillonites modified with tartrates are very selective solid catalysts for the Sharpless epoxidation, as well as for the oxidation of aromatic sulfides [140], Unfortunately, this research has not been reproduced by other authors. Therefore, a more classical strategy to modify different metal oxides with histidine was used by Moriguchi et al. [141], The catalyst showed a modest e.s. for the solvolysis of activated amino acid esters. Starting from these discoveries, Morihara et al. [142] created in 1993 the so-called molecular footprints on the surface of an Al-doped silica gel using an amino acid derivative as chiral template molecule. After removal of the template, the catalyst showed low but significant e.s. for the hydrolysis of a structurally related anhydride. On the same fines, Cativiela and coworkers [143] treated silica or alumina with diethylaluminum chloride and menthol. The resulting modified material catalyzed Diels-Alder reaction between cyclopentadiene and methacrolein with modest e.s. (30% e.e.). As mentioned in the Introduction, all these catalysts are not yet practically important but rather they demonstrate that amorphous metal oxides can be modified successfully. 

The above three examples involved reactions where the electron transfer takes place from the metal to the organic substrate. The reverse scenario can also be used in radical reactions via oxidative generation of cationic radical species, which can undergo coupling reactions. Kurihara et al. have used chiral ox-ovanadium species as a one-electron transfer oxidant to silylenol ethers in a hetero-coupling process [165]. Treatment of 246 with a catalyst prepared in situ from VOCI3/chiral alcohol/MS 4 A followed by addition of 247 provided the coupling product 248 (Scheme 63). 8-Phenyl menthol 251 was found to be... 

Thioanisolc. A system utilizing thio-anisole as an organic mediator was developed for the oxidation of secondary alcohols to ketones (Fig. 5 2-octanol to 2-octanone 99%, menthol to menthone 92%, cyclododecanol to cyclododecanone 75%) [43]. The use of 2,2,2-trifluoroethanol as a solvent in the mediatory system improved the yields [44]. 

LuneU E, Molander L, Ekberg K, Wahren J (2000) Site of nicotine absorption from a vapour inhaler-comparison with cigarette smoking. Eur J Clin Pharmacol 55(10) 737-741 MacDougaU JM, Fandrick K, Zhang X, Serafln SV, Cashman JR (2003) Inhibition of human liver microsomal (S)-nicotine oxidation by (—)-menthol and analogues. Chem Res Toxicol 16(8) 988-993... 

Electrochemical oxidation of enol acetates in an undivided cell gives monomeric products in parallel with the reactions of simple alkenes [47, 48]. Thus, in the reaction of menthol enol acetate 23, the a-acetoxyketone product arises from nucleophilic attack of acetate ion on the radical-cation while the enone product... 

Emberger and ITopp and Werkhoff and ITopp reported that there are significant sensory differences between the eight menthol and the four menthone enantiomers. (5)(-)-7-Hydroxy-6, 7-dihydrocitronellal has a lily-of-the-valley odor, while the odor of its enantiomer is weaker and has green, leaf like and minty notes.The enantiomers of cis- and trans-Tose oxide have closely similar odors with slight but detectable quality differences. ... 

TEMPO has been structurally modified to bring about new selectivities. Highly efficient anionic water-soluble TEME<), oil-in-water nanoemulsion containing TEME for oxidation of alcohols and a waste-free system were developed. Especially, the sterically less crowded azabicyclo-Af-oxyls oxidized /-menthol to Z-menthone with much higher efficiencies than TEME O (equation 23). ... 

SCHEME 122. Selective oxidation of bomeols and menthols with immobiUzed Mo catalysts and TBHP... 

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