2102-62-7Relevant articles and documents
Heteropoly acid catalysts for the synthesis of fragrance compounds from biorenewables: Isomerization of limonene oxide
Costa, Vinicius V.,Da Silva Rocha, Kelly A.,Kozhevnikov, Ivan V.,Kozhevnikova, Elena F.,Gusevskaya, Elena V.
, p. 244 - 250 (2013/04/10)
The liquid-phase isomerization of limonene oxide was studied in the presence of heteropoly acid catalysts in aprotic solvents in homogeneous and heterogeneous systems. Among the catalysts were bulk and silica-supported tungstophosphoric acid H3PW12O40 and its acidic Cs salt Cs0.5H0.5PW12O40 (CsPW). The reaction gave dihydrocarvone, a valuable fragrance intermediate, as the main product with turnover numbers of up to 8000. The nature of the solvent had a strong effect on reaction rate and selectivity. CsPW (0.1 mol%) was found to be a highly efficient and truly heterogeneous catalyst for this reaction, providing 82% yield of dihydrocarvone in 1,4-dioxane as a solvent under ambient conditions. This simple catalytic method represents economically attractive route to industrially important compounds starting from bio-renewable substrates easily available from essential oils. The Royal Society of Chemistry 2013.
Selective photosensitized oxidation and its catalytic regulation of monoterpene with molecular oxygen in different reaction media
You, Kuiyi,Yin, Dulin,Mao, Liqiu,Liu, Pingle,Luo, He'An
experimental part, p. 321 - 325 (2011/10/13)
The photo-catalytic oxidation of α-pinene, β-pinene and limonene with molecular oxygen sensitized by tetrachlorotetraiodo-fluorescein sodium salt (RB) has been studied in different reaction media under green light irradiation. Simple and efficient photosensitized oxidation equipment was employed successfully to improve the efficiency of the photosensitized reaction. The results indicate that the photosensitized oxidation products can be directly obtained without after-treatment by reductive reagent. Furthermore, it was found that the product distributions are remarkably affected by reaction media, and that N,N-dimethylformamide (DMF) can regulate the selectivity to products. In particular, the good selectivity (85%) to the main product (myrtenal) and the excellent conversion (99%) were obtained in the absence of any other catalysts when DMF was used as reaction solvent in the photosensitized oxidation of β-pinene. Moreover, the possible photosensitized oxidation reaction mechanism in different media was suggested in the present work.
Studies towards the taming of the 'carbocation' in the regioselective ring opening of epoxides to allylic alcohols
Chapman, Helen A.,Herbal, Karim,Motherwell, William B.
experimental part, p. 595 - 598 (2010/09/15)
Regioselective isomerisation of epoxides to allylic alcohols can be achieved using p-toluenesulfonic acid in the presence of 1,3- dimethylimidazolidin-2-one. Georg Thieme Verlag Stuttgart.
Mixed disproportionation versus radical trapping in titanocene(III)-promoted epoxide openings
Justicia, José,Jiménez, Tania,Morcillo, Sara P.,Cuerva, Juan M.,Oltra, J. Enrique
experimental part, p. 10837 - 10841 (2010/02/28)
The formation of either deoxygenation products or allylic alcohols from epoxides is observed when these substrates are treated with Cp2TiCl under anhydrous conditions. It seems that processes via trisubstituted radicals give allylic alcohols whereas processes via disubstituted radicals may give deoxygenation products or allylic alcohols depending on the structure of the original epoxide. This method allows a controlled access to these functional groups, providing a useful tool in organic synthesis. A mechanistic discussion for these transformations is reported.
Thermal degradation of terpenes: Camphene, Δ3-carene, limonene, and α-terpinene
Mcgraw, Gerald W.,Hemingway, Richard W.,Ingram Jr., Leonard L.,Canady, Catherine S.,Mcgraw, William B.
, p. 4029 - 4033 (2007/10/03)
Emissions from wood dryers have been of some concern for a number of years, and recent policy changes by the Environmental Protection Agency have placed emphasis upon the gaseous emissions that lead to the formation of particulate matter as small as 2.5 μm diameter. In this qualitative study, camphene, Δ3-carene, limonene, and α-terpinene were thermally degraded in the presence of air to determine the number and kind of oxidative degradation products that might be expected under drying conditions used in processing wood products. Various chromatographic methods were used to isolate the products for proof of structure by NMR and/or GC-MS. The degradation products resulted from dehydrogenations, epoxidations, double bond cleavages, allylic oxidations, and rearrangements. A number of compounds not previously associated with the thermal degradation of these terpenes were identified. Emissions from wood dryers have been of some concern for a number of years, and recent policy changes by the Environmental Protection Agency have placed emphasis upon the gaseous emissions that lead to the formation of particulate matter as small as 2.5 μm diameter. In this qualitative study, camphene, Δ3-carene, limonene, and α-terpinene were thermally degraded in the presence of air to determine the number and kind of oxidative degradation products that might be expected under drying conditions used in processing wood products. Various chromatographic methods were used to isolate the products for proof of structure by NMR and/or GC-MS. The degradation products resulted from dehydrogenations, epoxidations, double bond cleavages, allylic oxidations, and rearrangements. A number of compounds not previously associated with the thermal degradation of these terpenes were identified.
Pd-containing catalytic system for oxidative acetoxylation of alkenes
Romanenko,Tormyshev,Shteingarts
, p. 1549 - 1562 (2007/10/03)
Four-substituted cyclohexenes were used as examples for revealing the substituent effect on composition of products obtained by oxidative acetoxylation of alkenes catalyzed with Pd(II) acetate. The distribution of products is rationalized on assumption of relative stability of allylic anions and steric strains in (π-allyl)palladium intermediates. Stereoselective yield of trans-substituted endo-acetates is due to stabilizing effect of lower unoccupied orbital of the forming C-OAc bond and occupied orbitals of pseudoaxial C-H bonds at the cycle in the transition states. The substrates capable of this reaction are limited to alkenes with insignificant steric shielding of the double bond. The study of the influence on the process of the characteristics of oxidant used in the catalytic system revealed that the most significant difference is observed between catalysts prepared as homogeneous oxidative systems and those containing heterogeneous oxidant MnO2 or TiO2 as additive. 1998 MAHK "Hayka/Interperiodica".
Synthetic Chemistry with Fullerenes. Photooxygenation of Olefins
Tokuyama, Hidetoshi,Nakamura, Eiichi
, p. 1135 - 1138 (2007/10/02)
Under irradiation with visible or UV (>290 nm) light in the presence of molecular oxygen and a minute amount of fullerenes, olefins and dienes undergo ene and Diels-Alder reactions with singlet oxygen to give photooxygenation products.The regio- and stereoselectivities of the photooxygenation of β-myrcene, (+)-pulegone, 4-methylpent-3-en-2-ol, and (+)-limonene were very similar to those observed in known singlet oxygen reactions, indicating that the fullerene-sensitized reaction generates free singlet oxygen.The efficiency of fullerenes and conventional sensitizers was qualitatively examined by using the Diels-Alder reaction between 1O2 and furan-2-carboxylic acid as a probe.Among those examined, C70 was found to be the most effective.The reaction was the fastest and completed with as little as 0.0001 equiv of C70.C60 and hematoporphyrin were found to be of similar efficiency.The methanofullerene 13, which lacks one olefinic conjugation in the C60 core, was as good as C60 itself, but the aminofullerene 14, lacking six double bonds, was quite inferior.The fullerene carboxylic acid 15, which was previously shown to show considerable biochemical activity, was found to be capable of generating singlet oxygen in aqueous DMSO.
Photosensitized Oxygenation of Olefins with Zinc Tetraphenylporphine-1,4-Diazabicyclooctane Complex
Sakuragi, Masako,Ichimura, Kunihiro,Sakuragi, Hirochika
, p. 1944 - 1949 (2007/10/02)
In the presence of a proper amount of amines such as 1,4-diazabicyclooctane (DABCO) and piperidine, zinc tetraphenylporphine (ZnTPP) works as a not only apparently more effective but also more photoresistant sensitizer for singlet-oxygen oxygenation of olefins than in the absence of the amines.This is ascribed to the facts that ZnTPP forms a 1:1 complex with DABCO, and that DABCO coordinated to ZnTPP has no ability to quench singlet oxygen, as revealed by detection of singlet oxygen phosphorescence and product distributions in oxygenation of d-limonene, 1,2-dimethylcyclohexene, and 1-phenylcyclobutene.
TERPENOIDS OF THE ESSENTIAL OIL OF Ledum palustre
Klokova, M. V.,Khan, V. A.,Dubovenko, Zh. V.,Pentegova, V. A.,Berezovskaya, T. P.,Serykh, E. A.
, p. 278 - 281 (2007/10/02)
The chemical composition of the essential oil of crystal tea ledum of the ordinary variety growing in Western Siberia has been studied.Eighteen terpenoids have been isolated and identified from their spectral characteristics.Linalyl acetate, α-terpenyl ac
