- Aspect Cinetique des Substitutions Homolytiques Intramoleculaires. Decomposition de Peroxydes Insatures Derives du Pinane
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The decomposition, in dichloromethane, of β- and γ-unsaturated peroxides derived from pinane leads to transient tertiary pinanyl adduct radicals.The evolution of the reaction depends on the position of the insaturation.An intramolecular homolytic substitution gives functional pinanic epoxides in the first case; a β-scission followed by a hydrogen transfer yields functional p-menthenic peroxides in the second case.
- Montaudon, Evelyne,Bourgeois, Marie-Josephe
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Read Online
- Synthesis method of myrtenyl dihydrazide compound with fungal inhibition activity
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A synthesis method of a myrtenyl dihydrazide compound with fungal inhibition activity comprises the following steps of: firstly, selectively oxidizing alpha-pinene into myrtenyl, further oxidizing the myrtenyl into myrtenic acid, then reacting the myrtenic acid with thionyl chloride to obtain myrtenic acid acyl chloride, and finally, carrying out hydrazinolysis reaction with a series of substituted benzoyl hydrazine or 2-pyridine formyl hydrazine under an anhydrous condition, and synthesizing to obtain the myrtenyl dihydrazide compound. A bacteriostatic activity test shows that the myrtenyl dihydrazide compound has excellent broad-spectrum inhibitory activity on various plant pathogenic fungi, and can be used as a lead compound of a novel agricultural bactericide.
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Paragraph 0046; 0049-0050
(2021/07/17)
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- Synthesis of Myrtenal-Based Nanocellulose/Diacylhydrazine Complexes with Antifungal Activity for Plant Protection
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In search of novel bioactive compounds with excellent and broad-spectrum antifungal activity and nanopesticides with sustained releasing property, a series of novel myrtenal-based diacylhydrazines were designed, synthesized, and characterized. The preliminary bioassay showed that myrtenal-based 2-picolinyl hydrazide exhibited better or comparable antifungal activity than that of the commercial fungicides boscalid and chlorothalonil against the tested fungi. Furthermore, myrtenal-based nanocellulose was designed as a nanopesticide carrier and prepared from two biomass materials, bleached bagasse pulp and turpentine oil. Drug-loading capacities (LCs) of these carriers and sustained releasing properties of corresponding complexes were also evaluated, and the results indicated that the esterification reaction in the different solvents would affect the micromorphology of carriers, which was the important influential factor for loading or releasing drugs. To our delight, complex VIII-3 (LC = 0.32, total releasing amount/time = 99.8%/168 h) showed a macroporous framework with the drug evenly distributed across the opening network and staged drug-releasing performance that deserved further study as a nanopesticide.
- Cen, Bo,Duan, Wengui,Li, Baoyu,Lin, Guishan,Wang, Xiaoyu
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p. 12956 - 12965
(2021/11/17)
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- Monoterpene-containing substituted coumarins as inhibitors of respiratory syncytial virus (Rsv) replication
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Respiratory syncytial virus (RSV) is a critical cause of infant mortality. However, there are no vaccines and adequate drugs for its treatment. We showed, for the first time, that O-linked coumarin–monoterpene conjugates are effective RSV inhibitors. The most potent compounds are active against both RSV serotypes, A and B. According to the results of the time-of-addition experiment, the conjugates act at the early stages of virus cycle. Based on molecular modelling data, RSV F protein may be considered as a possible target.
- Borisevich, Sophia S.,Galochkina, Anastasia V.,Khomenko, Tatyana M.,Korchagina, Dina V.,Nikolaeva, Yulia V.,Petukhova, Galina D.,Salakhutdinov, Nariman F.,Shtro, Anna A.,Volcho, Konstantin P.
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- Selective Allylic Oxidation of Terpenic Olefins Using Co-Ag Supported on SiO2 as a Novel, Efficient, and Recyclable Catalyst
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Co-Ag supported on the SiO2 catalyst was synthesized by the sol-gel method and characterized using XRD, FT-IR, TG-DTG, BET, CV, and SEM/EDX analysis. The catalytic performance of the resulting catalyst was examined by the oxidation of mono and sesquiterpenic olefins using hydrogen peroxide and tert-butyl peroxide as oxidant agents. Various parameters such as catalyst amount, temperature, and solvents have been studied. The Co-Ag supported on the SiO2 catalyst showed a high activity, selectivity, and recyclability for the selected oxidation reaction.
- Aberkouks, Abderrazak,Mekkaoui, Ayoub Abdelkader,Ait Ali, Mustapha,El Firdoussi, Larbi,El Houssame, Soufiane
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- Asymmetric Synthesis of Oxygenated Monoterpenoids of Importance for Bark Beetle Ecology
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Herein we report the asymmetric syntheses of a number of oxygenated terpenoids that are of importance in the chemical ecology of bark beetles. These are pinocamphones, isopinocamphones, pinocarvones, and 4-thujanols (= sabinene hydrates). The camphones were synthesized from isopinocampheol, the pinocarvones from β-pinene, and the thujanols from sabinene. The NMR spectroscopic data, specific rotations, and elution orders of their stereoisomers on a chiral GC-phase (β-cyclodextrin) are also reported. This enables facile synthesis of pure compounds for biological activity studies and identification of stereoisomers in mixed natural samples.
- Ganji, Suresh,Svensson, Fredric G.,Unelius, C. Rikard
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p. 3332 - 3337
(2020/11/30)
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- A Simple, Mild and General Oxidation of Alcohols to Aldehydes or Ketones by SO2F2/K2CO3 Using DMSO as Solvent and Oxidant
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A practical, general and mild oxidation of primary and secondary alcohols to carbonyl compounds proceeds in yields of up to 99% using SO2F2 as electrophile in DMSO as both the oxidant and the solvent at ambient temperature. No moisture- and oxygen-free conditions are required. Stoichiometric amount of inexpensive K2CO3, which generates easy to separate by-products, is used as the base. Thus, 5-gram scale runs proceeded in nearly quantitative yields by a simple filtration as the work-up. The use of a polar solvent such as DMSO, which usually promotes competing Pummerer rearrangement, is also noteworthy. This protocol is compatible with a variety of common N-, O-, and S-functional groups on (hetero)arene, alkene and alkyne substrates (68 examples). The protocol was applied (99% yield) to a formal synthesis of the important cholesterol-lowering drug Rosuvastatin. (Figure presented.).
- Zha, Gao-Feng,Fang, Wan-Yin,Leng, Jing,Qin, Hua-Li
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supporting information
p. 2262 - 2267
(2019/04/17)
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- Oxidation of secondary alcohols using solid-supported hypervalent iodine catalysts
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It is shown how secondary alcohols are oxidized to provide the corresponding ketones by use of Oxone and solid-supported hypervalent iodine catalysts. Under experimentally simple conditions with acetonitrile at elevated temperatures, excellent conversions were achieved with low catalyst loadings (0.2-5 mol%) when employing the conjugates 5 and 6 derived from IBX and IBS. The catalysts are broadly applicable to a range of alcohol substrates. Of primary importance with respect to sustainability issues, the metal-free catalysts are easily removed from the reaction mixture through filtration, and they can be re-used in oxidation processes for multiple times, without loss of catalytic activity.
- Ballaschk, Frederic,Kirsch, Stefan F.
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supporting information
p. 5896 - 5903
(2019/11/11)
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- One-Pot Myrtenol Amination over Au, Au–Pd and Pd Nanoparticles Supported on Alumina
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Abstract: One-pot bio-based myrtenol amination was studied in the presence of alumina supported Au, Au–Pd and Pd nanoparticles subjected to the thermal treatment under oxidizing or reducing atmosphere. Myrtenol amination with aniline was carried out under nitrogen atmosphere (9?bar) at 453?K using toluene as a solvent. The effect of the active metal along with the influence of redox pre-treatment on the catalytic behavior in the hydrogen borrowing reaction was explored. The catalyst characterization was done by transmission electron microscopy, X-ray photoelectron spectroscopy, inductively coupled plasma optical emission spectroscopy, nitrogen adsorption. The active metal and the catalysts redox pretreatment affected more noticeably selectivity to the reaction products rather than myrtenol conversion. Monometallic Au/Al2O3 catalyst promoted predominantly formation of the target secondary amine and the corresponding imine without a significant impact of the side reaction of C=C bond hydrogenation in myrtenol, whereas monometallic Pd catalyst activated C=C bond resulting in its hydrogenation. At the same time in the presence of Au–Pd simultaneous hydrogenation of both C=C and C=N bond occurred. Au–Pd catalysts activated in oxygen and hydrogen showed different catalytic activity determined by the composition of surface active sites. Monometallic gold catalyst was more effective in the hydrogen transfer in the case of substrates with competitive unsaturated functional groups. Graphic Abstract: [Figure not available: see fulltext.].
- Demidova, Yu. S.,Simakova,Estrada,Beloshapkin,Suslov,Volcho,Salakhutdinov,Simakov,Murzin, D. Yu.
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p. 3454 - 3464
(2019/11/03)
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- The Taiji and Eight Trigrams chemistry philosophy of chiral iridium(III) complexes with triplex stereogenic centers
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Four novel chiral iridium(iii) complexes with triplex stereogenic centers were synthesized by introducing chiral carbon atoms into cyclometalated and ancillary ligands, and separated into eight isomers, which coincide with the old Chinese philosophy Eight Trigrams. The electron circular dichroism and circularly polarized luminescence spectra of four pairs of isomers show perfect mirror images with a dissymmetry factor (glum factor) of around 0.003.
- Yan, Zhi-Ping,Luo, Xu-Feng,Liao, Kang,Lin, Zi-Xuan,Wu, Zheng-Guang,Zhou, Yong-Hui,Zheng, You-Xuan
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supporting information
p. 4045 - 4048
(2018/03/26)
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- Synthesis and Bioactivity of N-(4-(N′-Substituted Sulfamoyl)Phenyl)Myrtenamides Containing a Heterocycle
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A series of N-(4-(N′-substituted sulfamoyl)phenyl)myrtenamides containing a heterocycle were designed and synthesized by a multiple-step procedure using α-pinene as starting material. All the synthesized compounds were characterized and analyzed by GC, HPLC, UV-vis, FTIR, NMR, GC-MS, and ESI-MS. The preliminary bioassay showed that, at 50 μg/mL, the target compounds exhibited a certain antifungal activity against the five tested fungi, in which compound 5f exhibited antifungal activity of 83.2% and 70.0% against Physalospora piricola and Alternaria solani, respectively. Moreover, compound 5d displayed herbicidal activity of 86.0% against the root of rape (Brassica campestris) at 100 μg/mL.
- Lin, Guishan,Duan, Wengui,Liu, Hongqiang,Ma, Yuan,Lei, Fuhou
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- Synthesis method for myrtenyl imidazo [2,1-b] [1,3,4] thiadiazole compound
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The invention discloses a synthesis method for a myrtenyl imidazo [2,1-b] [1,3,4] thiadiazole compound. The synthesis method comprises the following steps: firstly, selectively oxidizing alpha-pineneinto myrtenal; secondly, condensing the myrtenal with thiosemicarbazide to obtain myrtenyl thiosemicarbazone, and further carrying out oxidative cyclization to obtain myrtenyl thiadiazole; thirdly, carrying out cyclization reaction on the myrtenyl thiadiazole and series 2-bromophenylacetone under microwave irradiation to synthesize the myrtenyl imidazo [2,1-b] [1,3,4] thiadiazole compound. The synthesis method disclosed by the invention realizes synthesis of the myrtenyl imidazo [2,1-b] [1,3,4] thiadiazole compound for the first time; a bacteriostatic activity test shows that the myrtenyl imidazo [2,1-b] [1,3,4] thiadiazole compound has certain bacteriostatic activity and the application range of the alpha-pinene is widened.
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Paragraph 0011; 0014; 0015
(2018/11/03)
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- IBX as a catalyst for dehydration of hydroperoxides: Green entry to α,β-unsaturated ketones: Via oxygenative allylic transposition
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A catalytic transformation of allylic hydroperoxides into α,β-unsaturated carbonyl compounds using IBX as a dehydration catalyst is described. The combination of a singlet oxygen ene reaction and the IBX-catalyzed dehydration provides α,β-unsaturated carbonyl compounds from alkenes via oxygenative allylic transposition with H2O as the only byproduct.
- Kuga, Tetsuya,Sasano, Yusuke,Iwabuchi, Yoshiharu
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supporting information
p. 798 - 801
(2018/02/06)
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- Selectivity Modulation of the Ley–Griffith TPAP Oxidation with N-Oxide Salts
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A wide variety of novel non-hygroscopic N-oxide tetraphenylborate salts were synthesized and evaluated as co-oxidants in the Ley–Griffith (TPAP) oxidation of benzylic and allylic alcohols under non-anhydrous conditions. The novel DABCOO·TPB (2:1) salt was herein unearthed as a viable competitor to the first-generation NMO·TPB (2:1) salt, but more importantly gave increased performance under oxidative competition. X-ray crystal structure analysis and NMR spectroscopy revealed that depending on the crystallization conditions 1:1, 2:1 or 3:2 N-oxide–tetraphenylborate salts could be formed.
- Moore, Peter W.,Jiao, Yanxiao,Mirzayans, Paul M.,Sheng, Lexter Ng Qi,Hooker, Jordan P.,Williams, Craig M.
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p. 3401 - 3407
(2016/07/26)
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- Oxidation of alcohols by TBHP in the presence of sub-stoichiometric amounts of MnO2
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Commercially available activated MnO2 has been investigated as a catalyst for the oxidation of alcohols (phenylethanol, 4-methyl- and 4-methoxybenzyl alcohol, trans-cinnamyl alcohol, cyclohexanol, menthol, perillyl alcohol and myrtenol) by TBHP/decane or TBHP/water in MeCN. The activity is highest for benzylic and allylic alcohols. Secondary alcohols yield ketones with good selectivities, while the aldehydes generated from primary alcohols are further oxidized. The process competes with the TBHP catalyzed decomposition. It thus requires the use of excess TBHP and high catalyst loadings to achieve high conversions. However, the low cost of the reagents makes this new protocol convenient for the oxidation of reactive secondary alcohols. The study also suggests that MnO2 should be proscribed as a reagent to quench excess TBHP in oxidative processes when the synthetic target contains easily oxidizable alcohol functions and when carrying our detailed kinetic monitoring of oxidation processes.
- Bhaumik, Chanchal,Stein, Dominique,Vincendeau, Sandrine,Poli, Rinaldo,Manoury, éric
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p. 566 - 570
(2016/06/01)
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- N,N,N′,N′-Tetramethylenediamine dioxide (TMEDAO2) facilitates atom economical/open atmosphere Ley-Griffith (TPAP) tandem oxidation-Wittig reactions
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N,N,N′,N′-Tetramethylethylenediamine dioxide (TMEDAO2) was explored as a more atom economical co-oxidant for the Ley-Griffith oxidation of alcohols to aldehydes. TMEDAO2 was found to selectivity oxidise benzylic and allylic alcohols in comparable yields to that of the standard Ley-Griffith co-oxidant (NMO). Importantly TMEDAO2 facilitated tandem Ley-Griffith-Wittig reactions with stabilised ylides, in good to excellent yields, without the requirement of anhydrous conditions.
- Read, Christopher D. G.,Moore, Peter W.,Williams, Craig M.
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supporting information
p. 4537 - 4540
(2015/09/15)
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- Synthesis of Chiral Hydroxythiols Based on Oxygen-Containing α- And β-Pinene Derivatives
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Isomeric 10-thiopinan-3-ols including (1S,2S,3S,5R)-6,6-dimethyl-2-(sulfanylmethyl)bicyclo[3.1.1]heptan-3-ol were synthesized for the first time from oxygen-containing α- and β-pinene derivatives.
- Banina,Sudarikov,Krymskaya,Frolova,Kuchin
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p. 261 - 265
(2016/01/12)
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- NMO·TPB: A selectivity variation on the Ley-Griffith TPAP oxidation
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A non-hygroscopic tetraphenylborate salt of N-methylmorpholine-N-oxide (NMO) is reported (NMO·TPB), which modulates the standard Ley-Griffith oxidation such that benzylic and allylic alcohols are oxidised selectively. An attractive feature of this new protocol is that anhydrous conditions are not required for this selective tetra-n-propylammonium perruthenate (TPAP) oxidation, superseding the requirement of molecular sieves.
- Moore, Peter W.,Mirzayans, Paul M.,Williams, Craig M.
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supporting information
p. 3567 - 3571
(2015/03/04)
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- Hydrocarbon oxidation over Fe- and Cr-containing metal-organic frameworks MIL-100 and MIL-101-a comparative study
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Catalytic properties of Fe- and Cr-based metal-organic frameworks (MOFs) MIL-100 and MIL-101 have been assessed in two liquid-phase reactions: solvent-free allylic oxidation of alkenes (cyclohexene, α- and β-pinenes) with molecular oxygen and oxidation of anthracene (AN) with tert-butyl hydroperoxide (TBHP). In the oxidation of alkenes, the product selectivity strongly depends on the nature of metal (Fe or Cr) but, for the same metal, only slightly differs for the MIL-100 and MIL-101 structures. The Fe-containing MOFs afford the formation of unsaturated alcohols while Cr-based MOFs give mainly unsaturated ketones. Both Cr-MIL-100 and Cr-MIL-101 favor decomposition of cyclohexenyl hydroperoxide to produce 2-cyclohexen-1-one with 67-69% selectivity. Stability toward destruction reduced in the order Cr-MIL-101, Cr-MIL-100 > Fe-MIL-100 > Fe-MIL-101. In the oxidation of anthracene over both Cr-MOFs and Fe-MIL-101, the selectivity toward 9,10-anthraquinone (AQ) attained 100% at 92-100% AN conversion. The turnover frequency (TOF) decreased in the order Cr-MIL-101 > Fe-MIL-101 > Cr-MIL-100 > Fe-MIL-100. Cr-MIL-101 revealed superior catalytic performance in terms of AN conversion, AQ selectivity and TOF. Nearly quantitative yield of AQ was obtained after 1.5 h at 100 °C in chlorobenzene as solvent. No leaching of active metal occurred under optimal reaction conditions and the MOFs could be recycled several times without deterioration of the catalytic properties.
- Kholdeeva, Oxana A.,Skobelev, Igor Y.,Ivanchikova, Irina D.,Kovalenko, Konstantin A.,Fedin, Vladimir P.,Sorokin, Alexander B.
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- Spectroscopic and biocatalytic properties of a chlorophyll-containing extract in silica gel
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UV-Vis absorption and fluorescence spectra of chlorophyll a (in the form of spinach extract) in acetone solution and in silica gel showed a predominance of pigment dimers in its overall concentration and an evident transformation of chlorophyll a to pheophytin with time. The dimerization constant of chlorophyll a in acetone was log Kdim = 2.14, whereas the constants for chlorophyll a and pheophytin a in alcogel were log Kdim = 4.70 and log Kdim = 5.22, respectively. Biocatalytic experiments indicated the possibility of using the pigment embedded in silica gel, i.e. mainly its dimeric form, for biotransformation of α-pinene to pinocarveyl hydroperoxide, trans-pinocarveol, pinocarvone and myrtenal. The advantage of a heterogeneous biocatalytic system (composed of a solvent and silica gel) over a homogeneous system (single phase of chloroform) is the possibility of reusing the biocatalyst with about 10% preservation of its activity.
- Lipke, Agnieszka,Trytek, Mariusz,Fiedurek, Jan,Majdan, Marek,Janik, Ewa
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p. 158 - 164
(2013/10/08)
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- Homo- and heterogeneous α-pinene photooxidation using a protoporphyrin-derived amide
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6,7-Bis[3-(NIμ-tert-butyloxycarbonyllysine methyl ester)]-1,3,5,8-tetramethyl-2,4-divinylporphyrin (3) was synthesized and successfully immobilized in a silica matrix by a sol-gel method. Protoporphyrin (PP)-derived amide 3 showed much higher photostability than its parent PP-IX. Its UV/Vis absorption, excitation, and fluorescence spectra as well as its ability to generate 1O2 were measured both in solution and in the matrix. Subsequently, free and immobilized porphyrins 3 were used as sensitizers in the photooxidation of α-pinene, and their photocatalytic properties were compared. Newly synthesized protoporphyrin (PP)-derived amide 3 is more photostable than PP-IX. Because it is able to generate 1O2, it could be used as a biomimetic catalyst for the oxidation of α-pinene under visible light. After successful immobilization in a silica matrix, a transparent organic-inorganic hybrid was obtained that shows intensive luminescence. Copyright
- Trytek, Mariusz,Lipke, Agnieszka,Majdan, Marek,Pisarek, Sabina,Gryko, Dorota
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p. 1653 - 1658
(2013/04/23)
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- Nanosized sulfated zinc ferrite as catalyst for the synthesis of nopol and other fine chemicals
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A nanosized highly ordered mesoporous zinc ferrite (ZnFe2O 4; ZF) was synthesized via co-precipitation method, further sulfated with ammonium sulfate solution to obtain sulfated ZF (SZF) and have been used for the synthesis of nopol by Prins condensation of β-pinene and paraformaldehyde. The NH3-TPD and pyridine sorption DRIFT-IR studies revealed the significant enhancement in Lewis acidic sites of the zinc ferrite on sulfatation. The influence of various reaction parameters such as reaction temperature, effect of substrate stoichiometry and catalyst loading has been investigated. It gave 70% conversion of β-pinene with 88% selectivity to nopol. The spent catalyst was regenerated and reused successfully up to four cycles with slight loss in catalytic activity. The nanosized SZF catalyst was found to be highly active towards several other commercially important acid catalyzed reactions such as isomerization, acetalization and aldol condensation.
- Jadhav, Sumit V.,Jinka, Krishna Mohan,Bajaj, Hari C.
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- Selective photosensitized oxidation and its catalytic regulation of monoterpene with molecular oxygen in different reaction media
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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.
- You, Kuiyi,Yin, Dulin,Mao, Liqiu,Liu, Pingle,Luo, He'An
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experimental part
p. 321 - 325
(2011/10/13)
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- Aerobic copper/TEMPO-catalyzed oxidation of primary alcohols to aldehydes using a microbubble strategy to increase gas concentration in liquid phase reactions
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An efficient method for the synthesis of aldehydes was achieved by using air-microbubble techniques in aerobic copper/TEMPO-catalyzed oxidation of primary alcohols. Use of air-microbubbles to improve gas absorption into liquid phase is proven to be highly beneficial for gas/liquid phase reactions.
- Mase, Nobuyuki,Mizumori, Tomoya,Tatemoto, Yuji
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supporting information; experimental part
p. 2086 - 2088
(2011/03/22)
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- Peculiarities of β-pinene autoxidation
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The thermal oxidation of the renewable olefin β-pinene with molecular oxygen was experimentally and computationally investigated. Peroxyl radicals abstract weakly bonded allylic hydrogen atoms from the substrate, yielding allylic hydroperoxides (i.e., myrtenyl and pinocarvyl hydroperoxide). In addition, peroxyl radicals add to the C=C bond of the substrate to form an epoxide. It was found that a relatively high peroxyl radical concentration, together with the high rate of peroxyl cross-reactions, make radical-radical reactions surprisingly important for this particular substrate. Approximately 60% of these peroxyl cross-reactions lead to termination (radical destruction), keeping a radical chain length of approximately 4 at 10% conversion. Numerical simulation of the reaction-based on the proposed reaction mechanism and known or predicted rate constants-demonstrate the importance of peroxyl cross-reactions for the formation of alkoxyl radicals, which are the precursor of alcohol and ketone products. Copyright
- Neuenschwander, Ulrich,Meier, Emanuel,Hermans, Ive
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experimental part
p. 1613 - 1621
(2012/03/11)
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- Solvent-free chromium catalyzed aerobic oxidation of biomass-based alkenes as a route to valuable fragrance compounds
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Chromium containing mesoporous molecular sieves MCM-41 were shown to be an efficient heterogeneous catalyst for the liquid-phase aerobic oxidation of various monoterpenic alkenes under mild solvent-free conditions. The material was prepared through a direct hydrothermal method and characterized by ICP-AES, N2 adsorption-desorption, TEM, XRD, SAXS, and H2-TPR techniques. Characterizations suggest that chromium introduced in MCM-41 is essentially incorporated in the silica framework, with no extraframework chromium oxides being detected. Various oxygenated monoterpenoids important for the flavor and fragrance industry were obtained with high combined selectivities (75-92%) at 30-40% substrate conversions. The oxidation of β-pinene led almost exclusively to allylic mono-oxygenated derivatives, whereas limonene and α-pinene gave both epoxides and allylic oxidation products. The catalyst undergoes no metal leaching and can be easily recovered and re-used. A silica-included chromium catalyst prepared through a conventional sol-gel method showed activity comparable with that of Cr-MCM-41; however, selectivity was much lower.
- Robles-Dutenhefner, Patricia A.,Brand?o, Bruno B.N.S.,De Sousa, Líniker F.,Gusevskaya, Elena V.
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experimental part
p. 172 - 178
(2012/02/05)
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- Alkylation of phenol by myrtenol
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Alkylation of phenol by myrtenol in the presence of aluminum phenoxide and aluminum isopropoxide was studied in the temperature range 120-160°C. The reaction occurred with the formation of an array of alkylated phenols. Isomerization of the terpene substituent as a result of rearrangements of the bicyclic myrtenol structure was observed. The side reaction of myrtenol reduction occurred during the alkylation in the presence of aluminum isopropoxide. A significant number of compounds with two aromatic moieties was formed in the presence of aluminum phenoxide.
- Koroleva,Chukicheva, I. Yu.,Fedorova,Kuchin
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experimental part
p. 556 - 565
(2011/12/21)
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- Cobalt- and manganese-substituted ferrites as efficient single-site heterogeneous catalysts for aerobic oxidation of monoterpenic alkenes under solvent-free conditions
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Cobalt- and manganese-substituted ferrites were used as heterogeneous catalysts for liquid-phase aerobic oxidation of various monoterpenic alkenes. The materials were prepared by co-precipitation and characterized by Moessbauer spectroscopy, powder X-ray diffractometry, magnetization measurements, and elemental analysis. The results show that isomorphic substitution of iron in the ferrite crystalline structure occurred preferentially at octahedral positions and strongly affected its catalytic properties in the oxidation of monoterpenes. Various valuable oxygenated monoterpenic compounds were obtained with high combined selectivities (75-95%) at ca. 40% substrate conversions. Oxidations of β-pinene and 3-carene led almost exclusively to allylic mono-oxygenated derivatives, whereas limonene and α-pinene gave both epoxides and allylic products. The use of inexpensive catalyst and oxidant, solvent-free conditions, and high final product concentrations (ca. 40 wt%) are significant practical advantages of this environmentally friendly process. The catalysts undergo no metal leaching and can be easily recovered by the application of an external magnet and reused.
- Menini, Luciano,Pereira, Marcio C.,Parreira, Luciana A.,Fabris, Jose D.,Gusevskaya, Elena V.
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p. 355 - 364
(2008/09/18)
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- Synthesis of new enantiomeric 1,2-diamines containing a myrtenyl fragment
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Some new bi -and tridentate nitrogen-containing chiral ligands were synthesized on the basis of natural monoterpenoids, (+)-and (-)-myrtenals and (+)-myrtenol. A procedure was proposed for the synthesis of unsymmetrical ligands containing terpenoid and o-hydroxyphenyl fragments. Nauka/Interperiodica 2007.
- Dvornikova,Frolova,Kuchin,Beletskaya
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p. 352 - 358
(2007/10/03)
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- Synthetic scope of alcohol transfer dehydrogenation catalyzed by Cu/Al 2O3: A new metallic catalyst with unusual selectivity
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A method for the anaerobic oxidation of a wide series of alcohols including cyclohexanols and steroidal alcohols, has been set up. It relies on a transfer dehydrogenation reaction from the substrate alcohol to styrene catalyzed by a heterogeneous, reusable copper catalyst under very mild liquid phase experimental conditions (90°C, N2) and shows unusual selectivity. Thus, the method is selective for the oxidation of secondary and allylic alcohols even in the presence of unprotected primary and benzylic alcohols. Electronic effects and the choice of the hydrogen acceptor account for the selectivity observed.
- Zaccheria, Federica,Ravasio, Nicoletta,Psaro, Rinaldo,Fusi, Achille
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p. 6426 - 6431
(2008/09/20)
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- Development and comparison of the substrate scope of Pd-catalysts for the aerobic oxidation of alcohols
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(Chemical Equation Presented) Three catalysts for aerobic oxidation of alcohols are discussed and the effectiveness of each is evaluated for allylic, benzylic, aliphatic, and functionalized alcohols. Additionally, chiral nonracemic substrates as well as chemoselective and diastereoselective oxidations are investigated. In this study, the most convenient system for the Pd-catalyzed aerobic oxidation of alcohols is Pd(OAc)2 in combination with triethylamine. This system functions effectively for the majority of alcohols tested and uses mild conditions (3 to 5 mol % of catalyst, room temperature). Pd(IiPr)(OAc)2(H2O) (1) also successfully oxidizes the majority of alcohols evaluated. This system has the advantage of significantly lowering catalyst loadings but requires higher temperatures (0.1 to 1 mol % of catalyst, 60°C). A new catalyst is also disclosed, Pd(IiPr)(OPiv)2 (2). This catalyst operates under very mild conditions (1 mol %, room temperature, and air as the O2 source) but with a more limited substrate scope.
- Schultz, Mitchell J.,Hamilton, Steven S.,Jensen, David R.,Sigman, Matthew S.
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p. 3343 - 3352
(2007/10/03)
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- Catalytic allylic oxidation with a recyclable, fluorous seleninic acid
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In conjunction with iodoxybenzene as reoxidant perfluorooctylseleninic acid catalyzes the allylic oxidation of alkenes to enones in trifluoromethylbenzene at reflux in moderate to good yield. After a reductive workup with sodium metabisulfite, the catalyst is recovered by fluorous extraction in the form of bis(perfluorooctyl) diselenide, which, itself, serves as a convenient catalyst precursor.
- Crich, David,Zou, Yekui
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p. 775 - 777
(2007/10/03)
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- A well-defined complex for palladium-catalyzed aerobic oxidation of alcohols: Design, synthesis, and mechanistic considerations
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A breath of fresh air: A variety of alcohols are oxidized using 0.5-0.1 mol% of the catalyst, and in some cases the oxidation can simply be carried out open to the air (see scheme). Mechanistic insight into the mechanism is provided by a crystal structure that shows remarkable hydrogen bonds between the coordinated water and acetate ligands and an unprecedented large kinetic isotope effect.
- Jensen, David R.,Schultz, Mitchell J.,Mueller, Jaime A.,Sigman, Matthew S.
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p. 3810 - 3813
(2007/10/03)
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- A very mild and chemoselective oxidation of alcohols to carbonyl compounds
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matrixpresented Efficient oxidation of primary alcohols and β-amino alcohols to the corresponding aldehydes and α-amino aldehydes can be carried out at room temperature and in methylene chloride, using trichloroisocyanuric acid in the presence of catalytic TEMPO: aliphatic, benzylic, and allylic alcohols, and β-amino alcohols are rapidly oxidized without no overoxidation to carboxylic acids. Secondary carbinols are slowly oxidized so that the reaction is highly chemoselective.
- De Luca, Lidia,Giacomelli, Giampaolo,Porcheddu, Andrea
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p. 3041 - 3043
(2007/10/03)
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- Vesicle controlled selectivity in photosensitized oxidation of olefins
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The photooxidation of α-pinene (α-PE) and trans,trans-1,4-diphenyl- 1,3-butadiene (DPB) sensitized by 9,10-dicyanoanthracene (DCA) in mixed surfactant vesicles was selectively directed toward either the singlet oxygen mediated or the superoxide radical an
- Li, Hong Ru,Wu, Li Zhu,Tung, Chen Ho
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p. 1085 - 1086
(2007/10/03)
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- Controllable selectivity of photosensitized oxidation of olefins included in vesicles
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9,10-Dicyanoanthracene (DCA) sensitized photooxidation of α-pinene, trans-stilbene and trans,trans-1,4-diphenyl-1,3-butadiene in mixed surfactant vesicles was investigated. While the oxidation in homogeneous solution yields the products derived from both the energy transfer and the electron transfer pathways, that within Vesicles selectively yields either the singlet oxygen mediated or the superoxide radical anion mediated products depending on the status and location of the substrate and sensitizer molecules in the reaction medium. Upon incorporating the alkene in the bilayer membranes of one set of vesicles and DCA in another set of vesicles, the isolation of the substrate from the sensitizer prevents them from undergoing electron transfer. The singlet oxygen produced in the DCA-containing vesicles diffuses into the alkene-containing vesicles and reacts with the alkene. Thus, only the singlet oxygen oxidation products are obtained, and no product derived from the superoxide radical anion is detected. In contrast, incorporating both the sensitizer and the substrate within the same set of vesicles results in the two dissimilar molecules close to one another in the restricted space of the bilayer membranes of the vesicles. Thus, electron transfer from the alkenes to 1DCA* is enhanced, and the efficiency of the intersystem crossing from 1DCA* to 3DCA* is reduced. The photosensitized oxidation in this case only gives the products derived from the electron transfer pathway. Moreover, the reaction of singlet oxygen with DPB in vesicles results exclusively in the 1,2-cycloaddition products rather than the 1,4-cycloaddition product. This result indicates that the organized semirigid environment in vesicles prevents the olefin molecules from conformational change. (C) 2000 Elsevier Science Ltd.
- Li, Hong-Ru,Wu, Li-Zhu,Tung, Chen-Ho
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p. 7437 - 7442
(2007/10/03)
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- Palladium-Catalyzed Oxidation of Primary and Secondary Allylic and Benzylic Alcohols
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An efficient procedure for the oxidation of primary and secondary allylic and benzylic alcohols to aldehydes and ketones, respectively, has been achieved using catalytic Pd(OAc)2 in dimethyl sulfoxide (DMSO) with oxygen gas as the sole reoxidant of the palladium. Secondary substrates show increased reaction rates and improved yields with the addition of 2 equiv of NaHCO3. The reactions are free of acetal/ketal and ester byproducts.
- Peterson, Karl P.,Larock, Richard C.
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p. 3185 - 3189
(2007/10/03)
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- A novel and selective method for hydrolysis of acetals and ketals
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A series of cyclic and acyclic acetals and ketals were hydrolyzed to their corresponding carbonyl compounds by a catalytic amount of CBr4 (20%) in CH3CN/H2O solvent mixture under different energy sources, thermal or ultrasound. The highly chemoselective hydrolysis can be achieved under ultrasonic reaction condition.
- Lee, Adam S.-Y.,Cheng
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p. 14255 - 14262
(2007/10/03)
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- A convenient deoxygenation fo α,β-epoxy ketones to enones
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A new and efficient methodology for the deoxigenation of α,β-epoxy ketones to enones has been developed, using aminoiminomethanesulfinic acid (thioulea dioxide) as the reducing agent under phase transfer conditions. The epoxides of mesityl oxide, isophorane (-)-carvone, (+)-6-methyl-carvone, (+)-6-ethyl-carvone and (-)-myrtenal, were converted into their respectives enones in good to excellent yields.
- Dos Santos, Reginaldo B.,Brocksom, Timothy John,Brocksom, Ursula
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p. 745 - 748
(2007/10/03)
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- A Facile Synthesis of Aldehyde and Ketone via Sonochemical Barbier Reaction and Oxidation
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Methyl ketone is prepared by a sonochemical Barbier reaction of methyl iodide, magnesium powder and aldehyde in Benzene/THF (9/1) solvent in a commercial ultrasonic cleaning bath (39 kHz), followed by the addition of N-chlorosuccinimide (NCS) as an oxidizing agent.
- Lee, Adam Shih-Yuan,Kung, Chih-Chun
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- Deblocking of dithioacetals and oxathioacetals using periodic acid under mild nonaqueous conditions
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A novel method for the deblocking of the dithioacetals and oxathioacetals is described. Periodic acid under nonaqueous conditions has been used for the deprotection of the dithio- and oxathio-derivatives to the corresponding carbonyl compounds. This simple high-yield transformation is conveniently carried out in nonaqueous medium and works well with complex sensitive aldehydes and in the presence of other protective groups.
- Shi, Xiao-Xin,Khanapure, Subhash P.,Rokach, Joshua
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p. 4331 - 4334
(2007/10/03)
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- Novel allylic oxidation reagents
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Pentafluorobenzeneseleninic acid and 2-(N-oxido)pyridineseleninic anhydride were prepared and used efficiently in the oxidation of alcohols and in the allylic oxidation of alkenes.
- Barton, Derek H. R.,Wang, Tie-Lin
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p. 5149 - 5152
(2007/10/02)
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- Hydroboration. 90. Synthesis of 2-isobutyl- and 2-Isopropylapopinenes. Rates and Stoichiometry of the Hydroboration of 2-Organylapopinenes with Borane-Methyl Sulfide and Borane-Tetrahydrofuran
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Two higher analogues of α-pinene, 2-isobutyl- and 2-isopropylapopinenes, promising chiral auxiliaries for asymmetric hydroboration, were readily synthesized from α-pinene in good chemical yield.A quantitative study was made of the rates and stoichiometry of the hydroboration of a number of representative 2-organylapopinenes (2-R-apopinenes) with representative boranes, such as BH3*SMe2 (BMS) and BH3*THF, in order to develop a convenient procedure for the synthesis of mono- and bis(2-organylapoisopinocampheyl)boranes , under investigation as possible improved asymmetric hydroborating reagents.It was evident that the sterically bulkier 2-R-apopinenes such as 2-phenyl- and 2-isopropylapopinenes reacted with boranes at room temperature to form essentially RapBH2 in >/=95percent yield, while a yield of >/=90percent was realized in the case of 2-isobutylapopinene.However, α-pinene, and 2-ethyl- and 2-n-propylapopinenes smoothly reacted with boranes to form a mixture of RapBH2 and Rap2BH.Under the reaction conditions employed, 2-ethyl-, 2-n-propyl-, 2-isobutyl-, 2-phenyl-, and 2-isopropylapopinenes failed to produce clean Rap2BH.The rate of hydroboration decreased significantly with increase in bulk of the organyl group at the 2-position of the apopinene.
- Brown, Herbert C.,Dhokte, Ulhas P.
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p. 2025 - 2032
(2007/10/02)
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- Carbon-Carbon Bond Scission during the Reactions of Allylic Hydroperoxides with some Transition Metal Compounds. Result Relevant to a Recent Proposal
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The proposal that 4-exo closure of an allylic peroxyl radical can account for the titled reactions of pinocarveyl hydroperoxide has been considered in the light of literature data, along with the results of reactions carried out with a range of alternative copper and iron reagents and with the previously examinated reagents in the presence or absence of suitable traps: an acid-catalysed pathway is proposed to account for the observed scission reaction.
- Courtneidge, John L.
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p. 381 - 383
(2007/10/02)
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- Zinc Bismuthate Zn(BiO3)2. I. A Useful Oxidizing Agent for the Efficient Oxidation of Organic Compounds
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Zinc bismuthate is an easily prepared and a stable compound.It could be used as an oxidant in organic solvents under aprotic or in the presence of a catalytic amount of a protic solvent.Primary and secondary saturated, allylic, and benzylic alcohols are converted to their carbonyl compounds in high yields.Mildness of the reagent is shown by the oxidation of thiols to their disulfides in excellent yields.Thioethers are also oxidized to their corresponding sulfoxides in good yields.
- Firouzabadi, Habib,Mohammadpour-Baltork, Iraj
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p. 1131 - 1134
(2007/10/02)
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- Photooxygenation of olefins in the presence of titanium(IV) catalyst: A convenient 'one-pot' synthesis of epoxy alcohols
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The photooxygenation of olefins in the presence of transition-metal complexes derived from Ti, V, and Mo constitutes a convenient and efficient 'one-pot' synthesis of epoxy alcohols. First, singlet oxygen transforms the olefin via an ene reaction into its allylic hydroperoxide, and subsequently, the allylic hydroperoxide is converted via transition-metal-catalyzed oxygen transfer into its epoxy alcohol. From the point of view of the olefinic substrate, the oxygen transfer is intermolecular, one allylic hydroperoxide molecule serving as oxygen donor and the other as oxygen acceptor in the form of its allylic alcohol, the transition metal playing the role of a template for both as in the Sharpless epoxidation. Unlike the latter process, the hydroperoxide donor and the allylic alcohol acceptor are generated in situ and continually consumed via a novel oxygen-transfer chain sequence.
- Adam,Braun,Griesbeck,Lucchini,Staab,Will
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p. 203 - 212
(2007/10/02)
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- INDUCTION PAR LA LUMIERE DE L'OXYDATION DES COMPLEXES Η3-ALLYLPALLADIUM PAR L'OXYGENE MOLECULAIRE
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Irradiation at λ=366 nm of oxygenated solutions of η3-allylpalladium complexes leads to unsaturated carbonyl compounds.Substitution of the η3-allyl ligand by an electron withdrawing group could induce a regioselective oxidation of the allylic position farthest from this group.The efficiency of these reactions is sensible to the nature of the solvent.
- Muzart, J.,Pale, P.,Pete, J.P.,Riahi, A.
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p. 731 - 739
(2007/10/02)
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- THE ALLYLIC REARRANGEMENT OF HYDROPEROXIDES : THE ALLYLPEROXYL RADICAL
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The free-radical rearrangement of pinocarveyl hydroperoxide (1) or myrtenyl hydroperoxide (2) in hexane produces an equilibrium mixture of both hydroperoxides.The absence of carbon skeletal rearrangement suggests that the intermediate radical involved in hydroperoxide isomerization has its unpaired electron localized elsewhere than the α-carbon atom.The failure of oxygen to react with pinocarveyl, myrtenyl, and acyclic hydroperoxides (8) and (9) during the allylic rearrangement supports this suggestion.The kinetics of the rearrangement of 1-isopropyl-2-methylallyl hydroperoxide (8) is compatible with a mechanism in wich the intermediate is a common allylperoxyl radical produced directly from either allylic isomer.
- Brill, William F.
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p. 621 - 628
(2007/10/02)
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