Carvacrol, oxidation

Thymoquinone has been prepared directly from thymol by sulfonating and oxidizing the sulfonation mixture with manganese dioxide or potassium dichromate the same process has been successfully applied to carvacrol. The oxidation of sa ts of aminothymol with dichromate, ferric chloride, or nascent bromine also leads to satisfactory yields of thymoquinone. The above procedure is based on the observation that the diazonium salt obtained from aminothymol is almost quantitatively con-... 

When distilled with phosphorus pentoxide, camphor yields cymene, and with iodine, carvacrol. Both of these bodies are para-derivatives of benzene. On oxidation with nitric acid camphor yields many acids, of which the chief are camphoric acid, CjgHjgO, camphanic acid, CjoHj O, and camphoronic acid, CgHj Og. The constitution of these acids has an important bearing on that of camphor. Many formulae have been suggested for camphor during the past few years, but that of Bredt is now universally accepted, and has received complete confirmation by Komppa s synthesis of camphoric acid. This synthesis confirms the formula for camphoric acid as—... 

By heating carvacrol with alkalis, it is converted into isocuminic-acid, C(jH3(C3Hy)(OH)(COOH), melting at 93°. By oxidation with chromic acid mixture, thymoquinone results. This compound forms-crystalline tables melting at 45° to 46°. 

Use Solvents, synthetic-resin manufacture, metal polishes, organic synthesis (oxidation to hydroperoxides used as catalysts for synthetic-rubber manufacture cymene alcohols are made by hydrogenating the hydroperoxides). Purep-cresol and carvacrol are made from p-cymene. 

Reactions. Grignard reaction and hydrogenation of the appropriate methyl aryl ketone yielded isothymol.877 Carvacrol was formed in excellent (83%) yield on heating p-menth-l-ene oxide with Pd.878 Aromatic aldehydes can beprotected in situ by formation of a-aminoalkoxides and their O-trimethylsilyl ethers thus 4-formyl-benzoic acid could be protected and elaborated (Grignard reaction) into (264).879... 

The oxidation of p-cymene (103) usually gives rise to carvacrol (139) contaminated with varying amounts of thymol (140), but thallium trifluoroacetate in trifluoroacetic acid gives a thallium organic compound (137) that can be converted... 

It has been confirmed that selenium dioxide oxidation of car-3-ene gives 42% of the interesting oxabicyclic diene (288)/ together with some carvone, carvacrol, and a,p-dimethylstyrene. 

The cyclohexadienone formed from carvacrol, (5-isopropyl-2-methylphenol), by potassium periodate oxidation, or with iodic acid in ethanol, has been used to synthesise 3,10-dihydroxydielmentha-5,11-diene-4,9-dione, a monoterpene dimer from the plant, Callitris macleayana (ref. 18). 

An informative and amusing background to that unique material, camphor, has appeared. Its preparation by Oppenauer oxidation of the epimeric borneols occurs without epimerization. Epimerization does not occur in the presence of potassium t-butoxide in t-butyl alcohol, but it does with potassium isopropoxide in propan-2-ol." The reaction of camphor with phosphoric acid yields a complex mixture of m- and p-cymenes, 3,4-dimethylethylbenzene, 1,2,3,4-and 1,2,3,5-tetramethylbenzene, fenchone, carvenone, and carvacrol. A very detailed examination of the metal-ammonia reduction has revealed an intermediate camphor analogue of pinacol formed by association of a camphor anion radical with the metal cation. This intermediate was isolated and characterized. Other effects are discussed, such as that of adding a large excess of metal salt (LiBr, KBr, or NH Cl)." ... 

Butyl lactate Butyl laurate Butyl levulinate N-Butyl-2-methylbutyrate Butylparaben Butyl phenylacetate n-Butyl propionate Butyl salicylate Butyl stearate Butyl sulfide Butyl 10-undecenoate Butyl valerate n-Butyraldehyde n-Butyric acid Cadinene Camphene Caproic acid Caprylic alcohol Carvacrol Carvacryl ethyl ether Carveol 4-Carvomenthenol Carvone d-Carvone cis-Carvone oxide... 

Acenaphthene 6-Acetoxy-2,4-dimethyl-m-dioxane Alkyl dimethyl ethylbenzyl ammonium chloride 2-Amino-4-chloro-6-nitrophenol Ammonium polysulfide Ammonium thiosulfate Anilazine Aniline Arsenic pentoxide Basic yellow 2 Bromoacenaphthylene 3-Bromochloro-5,5-dimethyl hydantoin p-Bromo-p-nitrostyrene Cadmium Cadmium chloride Calcium oxide Calcium polysulfide Carvacrol Cetalkonium chloride Cetethyidimonium bromide... 

Phytochemistry Aboveground parts contain essential oil with menthol, menthone, carvacrol, and pulegone (Khalmatov 1964 Gulluce et al. 2007). Thirty-seven componnds were characterized representing 97 % of the total components detected. The major constituents of the oil were trans-piperitone oxide (64.51 %) and piperitenone oxide (12.34 % Baser et al. 1997a). The seeds contain a variety of different fatty acids (Gusakova et al. 1976). 

The antioxidant performance of carvacrol and thymol in the developed active films was also studied by DSC by determining their oxidation induction time, OIT (min) (Pospisil et al., 2003 Archodoulaki et al., 2006). The OTT value is defined as the time to the onset of an exothermic oxidation peak in oxidative atmosphere and it was determined by using oxygen and air, as the results obtained can be dependent on the type of atmosphere used for the analysis. 

The determination of OIT is considered a simple, reliable and fast method for the evaluation of the antioxidants efficiency [31], corresponding to relative measurements of the materials stability against oxidation. The evaluation of the antioxidant performance of carvacrol and th5miol in PP is important since they are supposed not only to play the role of active additives for food, but also to protect the pol5mier to oxidative degradation during processing and use. 

On the other hand, ethanol was the main volatile foimd in the head-space of bread in contact with the PPO film and stored at room temperature for 4 days. This compound was resulting from fermentation and/or lipid oxidation as it has been reported by other authors [30]. In this sense, commercial bread samples in contact witii PPT8 or PPC8 films after 4 days of storage were characterized by significantly lower amoimts of ethanol, suggesting a reduction on the lipid oxidation reactions by the presence of thymol and carvacrol. The improvement on the oxidative stability of bread could be attributed to the release of carvacrol and thymol increasing the shelf-life of bread. 

Linalool, linalyl acetate, fenchone, camphor Trans-calamenene, 5-cadinene, P-caryophyllene, leptospermone Piperitenone oxide, limonene, tltymol, carvacrol, p-cymene, P-caryophyllene, and y-terpinene... 

Metabolic pathways of menthol (137), menthone (149), thymol (179), and carvacrol methyl ether (202) are summarized in Figure 19.201. Menthol (137) is generally hydroxylated to give 1-hydroxy-(138), 2-hydroxy- (140), 4-hydroxy- (141), 6-hydroxy- (139), 7-hydroxy- (143), 8-hydroxy- (142), and 9-hydroxymenthol (144) and 1,8-dihydroxy- (146) and 7,8-dihydroxymenthol (148) (Asakawa et al., 1991 Takahashi et al., 1994 Van der Werf et al., 1997). Racemic menthyl acetate and menthyl chloroacetate are hydrolyzed asymmetrically by an esterase of microorganisms (Brit Patent, 1970 Moroe et al., 1971 Watanabe and Inagaki, 1977a,b). Menthone (149) is reductively metabolized to 137 and oxidatively metabolized to 3,7-dimethyl-6-hydroxyoctanoic acid (152), 3,7-dimethyl-... 

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