- Synthesis of the Female Sex Pheromone of the Citrus Mealybug, Planococcus citri
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The citrus mealybug, Planococcus citri (Risso) is a common pest in the Southern U. S. and the Mediterranean. Two alternative syntheses of the female sex pheromone, (1R)-(+)-cis-2,2-dimethyl-3-isopropenyl-cyclobutane methanol acetate, have been developed. Key transformations include an allylic oxidation of (1R)-(+)-α-pinene to (+)-R-verbenone, oxidative decarboxylation using RuCl3-NalO4, and methylenation with Zn/CH 2Br2/TiCl4.
- Passaro, Linda C.,Webster, Francis X.
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- Optical Control of Cannabinoid Receptor 2-Mediated Ca2+Release Enabled by Synthesis of Photoswitchable Probes
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Cannabinoid receptor 2 (CB2) is a promising target for the treatment of neuroinflammation and other diseases. However, a lack of understanding of its complex signaling in cells and tissues complicates the therapeutic exploitation of CB2 as a drug target. We show for the first time that benchmark CB2 agonist HU308 increases cytosolic Ca2+ levels in AtT-20(CB2) cells via CB2 and phospholipase C. The synthesis of photoswitchable derivatives of HU308 from the common building block 3-OTf-HU308 enables optical control over this pathway with spatiotemporal precision, as demonstrated in a real-time Ca2+ fluorescence assay. Our findings reveal a novel messenger pathway by which HU308 and its derivatives affect cellular excitability, and they demonstrate the utility of chemical photoswitches to control and monitor CB2 signaling in real-time
- Sarott, Roman C.,Viray, Alexander E. G.,Pfaff, Patrick,Sadybekov, Anastasiia,Rajic, Gabriela,Katritch, Vsevolod,Carreira, Erick M.,Frank, James A.
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- Individual stereoisomers of verbenol and verbenone express bioactive features
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Naturally occurring terpene core compounds have been used extensively in both pharmaceutical and cosmetic industry. However, since chirality of these compounds has profound influence on the level of their bioactivity, the aim of the present study was to a
- Ivanov, Marija,Kovalenko, Vitaly,Svirid, Anastasia,Kosti?, Marina,Petrovi?, Jovana,Stojkovi?, Dejan
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- Stereospecific synthesis of S-(?)-trans-verbenol and its antipode by inversion of sterically hindered alcohols
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S-(?)-trans-Verbenol (1) and its antipode, R-(+)-trans-verbenol (1′) have been confirmed as the critical pheromone components of bark beetles. Synthesis of these two active secondary alcohols (1 and 1′) from commercially available starting materials S-α-pinene and R-α-pinene was reported. The key steps were mainly depended on the effective SN2 stereo-inversion of the hydroxy group of sterically hindered alcohols (3 and 3′), using Mitsunobu reaction or hydrolysis of mesylate ester, alternatively. Our results provide a new and stereo-selectivity way to obtain optically active insect pheromones.
- Fang, Jia-Xing,Kong, Xiang-Bo,Liu, Fu,Zhang, Su-Fang,Zhang, Zhen
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- Highly Selective, Amine-Derived Cannabinoid Receptor 2 Probes
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The endocannabinoid (eCB) system is implied in various human diseases ranging from central nervous system to autoimmune disorders. Cannabinoid receptor 2 (CB2R) is an integral component of the eCB system. Yet, the downstream effects elicited by this G protein-coupled receptor upon binding of endogenous or synthetic ligands are insufficiently understood—likely due to the limited arsenal of reliable biological and chemical tools. Herein, we report the design and synthesis of CB2R-selective cannabinoids along with their in vitro pharmacological characterization (binding and functional studies). They combine structural features of HU-308 and AM841 to give chimeric ligands that emerge as potent CB2R agonists with high selectivity over the closely related cannabinoid receptor 1 (CB1R). The synthesis work includes convenient preparation of substituted resorcinols often found in cannabinoids. The utility of the synthetic cannabinoids in this study is showcased by preparation of the most selective high-affinity fluorescent probe for CB2R to date.
- Carreira, Erick M.,Grether, Uwe,Guba, Wolfgang,Osterwald, Anja,Sarott, Roman C.,Ullmer, Christoph,Westphal, Matthias V.,Zirwes, Elisabeth A.
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supporting information
p. 1380 - 1387
(2020/02/05)
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- Chiral terpene auxiliaries V: Synthesis of new chiral γ-hydroxyphosphine oxides derived from α-pinene
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New chiral regioisomeric γ-hydroxyphosphine ligands were synthesized from α-pinene. The key transformation was the thermal [2,3]-sigmatropic rearrangement of allyldiphenylphosphinites, obtained from (1R,2R,4S,5R)-3-methyleneneoisoverbanol and (1R,2R,3R,5R)-4-methyleneneoisopinocampheol, to allylphosphine oxides. Hydroxy groups were introduced stereoselectively through a hydroboration–oxidation reaction proceeding from the less hindered site providing a trans relationship between the hydroxy and the phosphine substituents.
- Kmieciak, Anna,Krzemiński, Marek P.
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supporting information
p. 2493 - 2499
(2019/12/11)
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- Crystallization of bisulfite derivatives of enantiomerically enriched verbenone
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After separation of crystalline bisulfite derivatives of enantiomerically enriched (1S)- and (1R)-verbenones, steam distillation of the filtrates afforded (1S)- and (1R)-verbenones whose optical purity was higher by 30 and 20%, respectively, than that of
- Kovalenko,Prat’ko,Prokhorevich
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p. 1598 - 1600
(2017/12/08)
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- Synthesis of new enantiomerically pure β-amino alcohols of the pinane series
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A series of new β-amino alcohols with pinane structure, (+)- and (?)-3α-amino-10β-pinan-4β-ols, 4β-amino-10β-pinan-3α-ol, and 4α-amino-10β-pinan-3α-ol have been synthesized with the goal of using them as organocatalysts in the aldol reaction of isatin with acetone.
- Frolova,Sudarikov,Alekseev,Banina,Slepukhin,Kutchin
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p. 335 - 343
(2017/05/09)
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- Synthesis of new monoterpene sulfonic acids and their derivatives
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The oxidation of monoterpene thiols with chlorine dioxide afforded new water-soluble sulfonic acids and their derivatives (sulfonothioates and sulfonyl chlorides). The reaction of terpene thiols with ClO2 gave the corresponding trisulfides. Sulfonothioates with a pinane skeleton showed antibacterial and antifungal activity.
- Grebyonkina,Lezina,Izmest’ev,Sudarikov,Pestova,Rubtsova,Kutchin
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p. 860 - 868
(2017/08/02)
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- Cis-dioxo-Mo(VI) salophen complex supported on Fe3O4@SiO2 nanoparticles as an efficient magnetically separable and reusable nanocatalyst for selective epoxidation of olefins
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In this work, paramagnetic Fe3O4/SiO2 nanoparticles were synthesized, characterized and functionalized with dioxo-Mo(VI) tetradentate Schiff base complex and characterized using IR spectroscopy, X-ray powder diffraction spectroscopy, scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometry, diffuse reflectance spectroscopy and atomic absorption spectroscopy. Catalyst was used for the selective epoxidation of cyclooctene, cyclohexene, styrene, indene, α-pinene, 1-hepten, 1-octene, 1-dodecen and trans-stilbene using tert-butyl hydroperoxide as oxidant in 1,2-dichloroethane. This catalyst is efficient for oxidation of cyclooctene with a 100% selectivity for epoxidation with 100% conversion in 1?h. After the reaction, the magnetic nanocatalyst was easily separated by simply applying an external magnetic field and was used at least five successive times without significant decrease in conversion.[Figure not available: see fulltext.].
- Bezaatpour, Abolfazl,Khatami, Sahar,Nejati, Kamellia
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p. 2105 - 2115
(2017/09/13)
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- Potent Odorants of Characteristic Floral/Sweet Odor in Chinese Chrysanthemum Flower Tea Infusion
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An investigation using the aroma extract dilution analysis (AEDA) technique applied to the aroma concentrates prepared from the tea infusions of two different types of Chinese chrysanthemum flowers (flower buds, blooming flowers) revealed that 29 aroma peaks were detected in the aroma concentrates, and 17 compounds were newly identified or tentatively identified in the chrysanthemum flower tea. AEDA also revealed that the aroma peaks having high flavor dilution factors mainly consisted of a floral/sweet note in addition to metallic and phenol-like/spicy notes. Among them, four aroma peaks having a floral/sweet were identified as verbenone, ethyl 3-phenylpropanoate, propyl 3-phenylpropanoate, and ethyl cinnamate, and a semiquantitative analysis revealed that the flower buds were rich in these compounds. Furthermore, a chiral analysis revealed that (-)-verbenone existed in both flowers at a 3 times higher concentration than (+)-verbenone. Additionally, because the detection threshold of (-)-verbenone was lower than that of the (+)-verbenone, it is concluded that the (-)-isomer was a main contributor of the aroma peak of verbenone in the chrysanthemum flower tea.
- Kaneko, Shu,Chen, Jingxiu,Wu, Jieming,Suzuki, Yuto,Ma, Lin,Kumazawa, Kenji
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p. 10058 - 10063
(2017/11/30)
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- Kinetic study of α-pinene allylic oxidation over FePcCl16-NH2-SiO2 catalyst
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The kinetic of α-pinene oxidation over an iron hexadecachlorinated phthalocyanine immobilized on modified silica (FePcCl16-NH2-SiO2) with t-butyl hydroperoxide (TBHP) as oxidant is proposed. Reaction rates were calculated by the initial reaction rate method from the data obtained in a batch reactor, and compared with kinetic expressions proposed from mechanisms based on Langmuir Hinshelwood Hougen Watson (LHHW) and power-rate law models. The kinetic parameters were estimated from the experimental data by optimization using the Genetic Algorithm. A kinetic expression based on LHHW model with the adsorption of α-pinene, TBHP and the main reaction products (verbenone, α-pinene epoxide and verbenol) on the surface of the catalyst predicted the experimental data with good accuracy (R2?=?0.986). The apparent activation energy of α-pinene allylic oxidation over FePcCl16-NH2-SiO2/TBHP was 40.08?kJ/mol. α-Pinene conversion of 83.7% was obtained after 23?h with a selectivity to verbenone of 23%. Under the reaction conditions leaching of the active species was not observed; however, the effect of radicals in the bulk liquid phase was demonstrated, confirming that the reaction involves a combination of both heterogeneous and homogeneous pathways. The catalyst can be used at least in seven cycles without loss of α-pinene conversion nor verbenone selectivity.
- Becerra, Jaime-Andrés,González, Lina-María,Villa, Aída-Luz
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- Scalable and sustainable electrochemical allylic C-H oxidation
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New methods and strategies for the direct functionalization of C-H bonds are beginning to reshape the field of retrosynthetic analysis, affecting the synthesis of natural products, medicines and materials. The oxidation of allylic systems has played a prominent role in this context as possibly the most widely applied C-H functionalization, owing to the utility of enones and allylic alcohols as versatile intermediates, and their prevalence in natural and unnatural materials. Allylic oxidations have featured in hundreds of syntheses, including some natural product syntheses regarded as € classics €. Despite many attempts to improve the efficiency and practicality of this transformation, the majority of conditions still use highly toxic reagents (based around toxic elements such as chromium or selenium) or expensive catalysts (such as palladium or rhodium). These requirements are problematic in industrial settings; currently, no scalable and sustainable solution to allylic oxidation exists. This oxidation strategy is therefore rarely used for large-scale synthetic applications, limiting the adoption of this retrosynthetic strategy by industrial scientists. Here we describe an electrochemical C-H oxidation strategy that exhibits broad substrate scope, operational simplicity and high chemoselectivity. It uses inexpensive and readily available materials, and represents a scalable allylic C-H oxidation (demonstrated on 100 grams), enabling the adoption of this C-H oxidation strategy in large-scale industrial settings without substantial environmental impact.
- Horn, Evan J.,Rosen, Brandon R.,Chen, Yong,Tang, Jiaze,Chen, Ke,Eastgate, Martin D.,Baran, Phil S.
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- Zeolite-Y immobilized Metallo-ligand complexes: A novel heterogenous catalysts for selective oxidation
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Transition metal [M?=?Co(II), Cu(II)] complexes of H2L1 and H2L2 ligands have been prepared as neat and nanohybrid zeolite-Y immobilized complexes. The various analytical tools such as FTIR, ICP-AES, elemental analysis, UV–vis, Brunauer, Emmett and Teller (BET) surface area analysis, Thermal analysis, scanning electron micrographs, Powder XRD, conductivity, magnetic moment, and AAS were employed for the characterization of the prepared catalysts. Among all catalysts, the [Cu(L1)]-Y (heterogeneous) and [Cu(L1)] (homogeneous) have offered high activity and selectivity over oxidation of cyclohexene. Moreover, the [Cu(L1)] and [Cu(L1)]-Y were employed as catalyst over various organic substrates at identical reaction condition. The immobilized catalyst [Cu(L1)]-Y is found to be moderate active over oxidation of cyclohexane (75.2%,), benzene (8.21%), phenol (14.5%), styrene (87.5), benzyl alcohol (21.5%), limonene (11.2%), α-pinene (9.15%), and cyclooctane (76.8%) with high TON values (21942-2054). The mechanistic study using UV–vis and FTIR suggests the participation of active metalperoxo species, which is reinforced by its high catalytic activity over limonene (16.3%) in the absence oxidant.
- Godhani, Dinesh R.,Nakum, Haresh D.,Parmar, Digvijaysinh K.,Mehta, Jignasu P.,Desai, Nisheeth C.
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p. 105 - 116
(2016/09/07)
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- Aerobic oxidation of α-pinene catalyzed by carbon nanotubes
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Carbon nanotubes (CNTs) and nitrogen-doped CNTs (NCNTs) as metal-free catalysts exhibited an excellent activity in the selective oxidation of α-pinene with molecular oxygen as the terminal oxidant. Two distinct pathways, i.e. epoxidation and allylic oxidation, were active in this reaction. Enhancement of epoxidation was observed over CNTs, yielding the highest epoxidation/allylic oxidation products ratio. Excellent activity was achieved over NCNTs, giving 54.5% α-pinene conversion and 272.4 mmol g-1 h-1 mass-normalized activity, which compete with that of the state-of-the-art metal catalysts. Allylic oxidation was enhanced over NCNTs, using which equimolar amounts of epoxide and allylic products were produced. Thus, N-doping boosted the overall conversion and the yields of both epoxidation and allylic oxidation products, which was supported by the results of theoretical simulation.
- Cao, Yonghai,Li, Yuhang,Yu, Hao,Peng, Feng,Wang, Hongjuan
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p. 3935 - 3944
(2015/08/03)
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- Synthesis and analgesic activity of stereoisomers of 2-(3(4)-hydroxy-4(3)-methoxyphenyl)-4,7-dimethyl-3,4,4a,5,8,8a-hexahydro-2H-chromene-4,8-diols
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2-(3(4)-Hydroxy-4(3)-methoxyphenyl)-4,7-dimethyl-3,4,4a,5,8,8a-hexahydro-2H-chromene-4,8-diols were found recently to possess high analgesic activity and low acute toxicity. Stereoisomers of these compounds with high optical purity were synthesized from (+)- and (-)-α-pinenes for the first time in this work. The structure of (4S)-4b isomer was confirmed by the XRD data. Studies of analgesic activity of the resulting products demonstrated that neither the absolute configuration nor cis- or trans-arrangement of vicinal oxygen atoms plays a significant role in manifestation of analgesic effect by these isomers, while only (4S)-4b isomer, but not (4R)-4b demonstrated the analgesic effect.
- Pavlova, Alla,Mikhalchenko, Oksana,Rogachev, Artem,Il'Ina, Irina,Korchagina, Dina,Gatilov, Yuriy,Tolstikova, Tat'Yana,Volcho, Konstantin,Salakhutdinov, Nariman
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p. 3821 - 3830
(2015/10/06)
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- Catalytic activity of an iron(III) Schiff base complex bound in a polymer resin
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An iron(III)-ferrocene complex and its heterogeneous analogue bound in a polymer resin have been prepared and employed as catalysts for the oxidation of various organic substrates. Characterization of the heterogeneous and homogeneous complexes was done by SEM, EDAX, TGA, FT-IR, DRS-UV, and spectroscopy. The catalyst's activity, stability, and reusability were investigated through industrially relevant oxidation reactions. The solid iron(III)-ferrocene Schiff base complex gave more effective results than the solid-supported ferrocene Schiff base ligand. The antimicrobial activities of the molecular complex and free ligand were studied for Gram-positive and Gram-negative bacteria.
- Islam, Sk. Manirul,Paul, Sumantra,Roy, Anupam Singha,Banerjee, Satabdi,Ghosh, Kajari,Dey, Ram Chandra,Santra
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p. 675 - 682
(2013/09/23)
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- Oxidation of α-pinene by atmospheric oxygen in the supercritical CO2-ethyl acetate system in the presence of Co(II) complexes
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The reactivity of monoterpene α-pinene in a flow reactor in the presence of cobalt catalyst in a complex supercritical solvent consisting of CO2 and ethyl acetate is studied over the temperature range of 190-320°C and a pressure range of 110-125 atm. It was found that the main isomerization products include compounds with bicyclo[2.2.1]heptane and p-menthane backbones; the reaction is accompanied by partial racemization. The formation of oxidation products is observed in the presence of air, with epoxydation rather than allylic oxidation being the predominant process at the first stage. The oxidized products (campholenic aldehyde, verbenone, pinocamphone) are shown to be formed with a high enantioselectivity; the formation of acetoxylation products is observed at temperatures above 200°C.
- Anikeev,Ilina,Kurbakova,Nefedov,Volcho,Salakhutdinov
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experimental part
p. 190 - 195
(2012/03/12)
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- Highly efficient epoxidation of styrene and α-pinene with air over Co2+-exchanged ZSM-5 and Beta zeolites
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Co2+-exchanged zeolites (prepared simply by ion-exchange method) have been used in the epoxidation of styrene and α-pinene with air, in which Co-ZSM-5 and Co-Beta without any organic Schiff-base ligand or additive behaved as highly efficient catalysts. Co-ZSM-5 and Co-Beta achieved 88.4-92.4 mol% conversion with the overall selectivity of 94.6-96.6% for the epoxidation of styrene, and 92.8-90.6 mol% conversion with the selectivity of 86.1-88.3% for the epoxidation of α-pinene, respectively. Recycling studies and control experiments showed the stability and recyclability of Co-ZSM-5 and Co-Beta in the epoxidation reaction.
- Tang,Lu,Zhou,Lei,Niu,Fan,Xia
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experimental part
p. 68 - 71
(2012/06/01)
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- Highly potent activity of (1R,2R,6S)-3-methyl-6-(prop-1-en-2-yl)cyclohex-3- ene-1,2-diol in animal models of parkinson's disease
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(1R,2R,6S)-3-Methyl-6-(prop-1-en-2-yl)cyclohex-3-ene-1,2-diol 1 possesses potent antiparkinsonian activity in both MPTP and haloperidol animal models. The use of compound 1 resulted in nearly full recovery of the locomotor and exploratory activities and was as effective as the comparator agent (levodopa). All eight stereoisomers of compound 1 have been synthesized and the influence of the absolute configuration on the antiparkinsonian activity of compound 1 was shown.
- Ardashov, Oleg V.,Pavlova, Alla V.,Il'ina, Irina V.,Morozova, Ekaterina A.,Korchagina, Dina V.,Karpova, Elena V.,Volcho, Konstantin P.,Tolstikova, Tat'yana G.,Salakhutdinov, Nariman F.
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supporting information; experimental part
p. 3866 - 3874
(2011/08/07)
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- Olefin epoxidation with tert-BuOOH catalyzed by vanadium polyoxometalate immobilized on ionic liquid-modified MCM-41
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Preparation and characterization of vanadium-containing polyphosphomolybdates supported on ionic liquid-modified MCM-41, MCM-41-Im, are reported. The catalyst, [PVMo@MCM- 41-Im], was characterized by elemental analysis, X-ray diffraction, scanning electron microscopy and also FT-IR, and UV-Vis spectroscopic methods. This heterogeneous catalytic system was applied for efficient epoxidation of various olefins in the presence of tert-BuOOH in 1,2-dichloroethane under reflux. The catalyst can be reused several times without apparent loss of its catalytic performance.
- Hajian, Robabeh,Tangestaninejad, Shahram,Moghadam, Majid,Mirkhani, Valiollah,Mohammadpoor-Baltork, Iraj,Khosropour, Ahmad Reza
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scheme or table
p. 4134 - 4144
(2012/03/26)
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- Antiviral activity of 3-methyl-6-(prop-l-en-2-yl)cyclohex-3-ene-l,2-diol and its derivatives against influenza A(HlNl)2009 virus
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A number of new derivatives of monoterpenoid with a para-menthane framework 3-methyl-6-(prop-1-en-2- yl)cyclohex-3-ene-1,2-diol (-)-3 were synthesized. The antiviral activity of (-)-3 and its derivatives against the pandemic influenza virus A/California/07/09 (H1N1)v was studied in vitro. Compound (-)-3 was found to be active against this virus (selectivity index 7.5); for mononicotinate (+)-6 the selectivity index was 17. The absolute configuration of compound 6 was shown to be critical for its antiviral activity.
- Ardashov, Oleg V.,Zarubaev, Vladimir V.,Shtro, Anna A.,Korchagina, Dina V.,Volcho, Konstantin P.,Salakhutdinov, Nariman F.,Kiselev, Oleg I.
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p. 375 - 380
(2012/06/01)
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- Synthesis, catalytic oxidation and antimicrobial activity of copper(II) Schiff base complex
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A new polymer supported Cu(II) Schiff base complex was synthesized. The solid complex was characterized by Fourier transform infrared spectroscopy (FT-IR), UV-vis diffuse reflectance spectroscopy (DRS), thermogravimetric analysis (TGA) and scanning electron microscope (SEM). Its homogeneous analogue was also prepared. The catalytic performances of the copper complex in oxidation reactions were evaluated for both homogeneous and heterogeneous systems. The copper(II) complex was found to be efficient catalyst for the oxidation of alkenes, alkanes and aromatic alcohols in the presence of hydrogen peroxide as oxidant at room temperature. The catalytic investigation revealed that the solid complex performs better than the homogeneous one as an oxidation catalyst. The solids containing the immobilized complex can be recovered from the reaction medium and reused almost five times, maintaining good catalytic activity. Furthermore, the in vitro toxicity of the ligand and complex was tested against the growth of bacterial species, viz., Staphylococcus aureus and Escherichia coli.
- Islam,Roy, Anupam Singha,Mondal, Paramita,Mubarak, Manir,Mondal, Sanchita,Hossain, Dildar,Banerjee, Satabdi,Santra
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experimental part
p. 106 - 114
(2011/05/12)
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- Selective oxidation of olefins catalyzed by polymer-anchored nickel(II) complex in water medium
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Selective oxidation of olefins has been carried out in water medium with tert-butylhydroperoxide (TBHP, 70% aqueous) as an oxidant using polymer-anchored Ni(II) complex as a catalyst. Several parameters were varied to optimize the reaction conditions. Under the optimized reaction conditions olefins gave selectively allylic oxidation products. The present polymer anchored Ni(II) complex can be recycled five times without any appreciable loss in catalytic activity.
- Islam, Manirul,Hossain, Dildar,Mondal, Paramita,Roy, Anupam Singha,Mondal, Sanchita,Mobarak, Manir
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scheme or table
p. 3765 - 3770
(2011/09/21)
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- Oxidation of secondary terpene alcohols by chlorine dioxide
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Secondary terpene alcohols cis- and trans-verbenol, neo-iso-verbanol, borneol, iso-borneol, and menthol were oxidized by chlorine dioxide into the corresponding ketones. It was shown that the nature of the solvent and catalyst and the structure of the starting compound, including the stereochemistry of the hydroxyl, influenced the oxidation process.
- Frolova,Popov,Rubtsova,Kuchin
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experimental part
p. 724 - 727
(2009/05/09)
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- Formation of trans-verbenol and verbenone from α-pinene catalysed by immobilised Picea abies cells
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Both enantiomers and the raceinate of α-pinene were transformed by Picea abies cells immobilised on alginate. The main products were cis- and trans-verbenol, the later being further transformed to verbenone. The enantiomeric purity of each product more or less corresponded to that of the substrate. Transformation by free cells was faster than that by the immobilised cells. The ratio of products differed to some extent between the transformation by tree and immobilised cells.
- Vanek, Tomas,Halik, Jan,Vankova, Radmila,Valterova, Irena
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p. 321 - 325
(2007/10/03)
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- Chiral synthesis of maconelliol: A novel cyclobutanoid terpene alcohol from pink hibiscus mealybug, Maconellicoccus hirsutus
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The chiral synthesis of maconelliol, [2,2-dimethyl-3-(1-methylethylidene) cyclobutyl] methanol, the alcohol moiety of the major sex pheromone component isolated from the pink hibiscus mealybug, Maconellicoccus hirsutus, is described. The compound was synthesized in six steps from alpha-pinene and the key step is dehydration of 5 to 7 through the intermediate 6. The absolute configuration of the naturally occurring maconelliol was determined as R.
- Zhang, Aijun,Nie, Junying,Khrimian, Ashot
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p. 9401 - 9403
(2007/10/03)
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- Allylic and benzylic oxidation using cobalt(II) alkyl phosphonate modified silica
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The allylic and benzylic oxidation of a range of substrates proceeds in good yield using catalytic quantities of cobalt(II) alkyl phosphonate modified silica and tert-butyl hydroperoxide.
- Jurado-Gonzalez, Magdalena,Sullivan, Alice C.,Wilson, John R. H.
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p. 4283 - 4286
(2007/10/03)
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- Transformation of α-pinene using Picea abies suspension culture
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α-Pinene, both as the pure enantiomers and as the racemate, was transformed mainly to trans-verbenol by treatment with a Picea abies suspension cell culture. These reactions were followed by a slow transformation of the verbenol to verbenone, which was not transformed further. trans-Pinocarveol, myrtenol, cis-verbenol, and α-terpineol were byproducts of intermediate abundance. When subjected to the action of the suspension culture, cis-verbenol was not only transformed to verbenone but also isomerized to trans-verbenol. The transformation of α-pinene was fast, and the products were detected within one minute. The absolute configuration of the major products corresponded to that of the starting α-pinene enantiomer.
- Lindmark-Henriksson, Marica,Isaksson, Dan,Sjoedin, Kristina,Hoegberg, Hans-Erik,Vanek, Tomas,Valterova, Irena
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p. 337 - 343
(2007/10/03)
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- Molecular recognition in (+)-α-pinene oxidation by cytochrome P450cam
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Oxygenated derivatives of the monoterpene (+)-α-pinene are found in plant essential oils and used as fragrances and flavorings. (+)-α-Pinene is structurally related to (+)-camphor, the natural substrate of the heme monooxygenase cytochrome P450cam from Pseudomonas putida. The aim of the present work was to apply the current understanding of P450 substrate binding and catalysis to engineer P450cam for the selective oxidation of (+)-α-pinene. Consideration of the structures of (+)-camphor and (+)-α-pinene lead to active-site mutants containing combinations of the Y96F, F87A, F87L, F87W, and V247L mutations. All mutants showed greatly enhanced binding and rate of oxidation of (+)-α-pinene. Some mutants had tighter (+)-α-pinene binding than camphor binding by the wild-type. The most active was the Y96F/V247L mutant, with a (+)-α-pinene oxidation rate of 270 nmol (nmol of P450cam)-1 min-1, which was 70% of the rate of camphor oxidation by wild-type P450cam. Camphor is oxidized by wild-type P450cam exclusively to 5-exo-hydroxycamphor. If the gem dimethyl groups of (+)-α-pinene occupied similar positions to those found for camphor in the wild-type structure, (+)-cis-verbenol would be the dominant product. All P450cam enzymes studied gave (+)-cis-verbenol as the major product but with much reduced selectivity compared to camphor oxidation by the wild-type. (+)-Verbenone, (+)-myrtenol, and the (+)-α-pinene epoxides were among the minor products. The crystal structure of the Y96F/F87W/V247L mutant, the most selective of the P450cam mutants initially examined, was determined to provide further insight into P450cam substrate binding and catalysis. (+)-α-Pinene was bound in two orientations which were related by rotation of the molecule. One orientation was similar to that of camphor in the wild-type enzyme while the other was significantly different. Analysis of the enzyme/substrate contacts suggested rationalizations of the product distribution. In particular competition rather than cooperativity between the F87W and V247L mutations and substrate movement during catalysis were proposed to be major factors. The crystal structure lead to the introduction of the L244A mutation to increase the selectivity of pinene oxidation by further biasing the binding orientation toward that of camphor in the wild-type structure. The F87W/Y96F/L244A mutant gave 86% (+)-cis-verbenol and 5% (+)-verbenone. The Y96F/L244A/V247L mutant gave 55% (+)-cis-verbenol but interestingly also 32% (+)-verbenone, suggesting that it may be possible to engineer a P450cam mutant that could oxidize (+)-α-pinene directly to (+)-verbenone. Verbenol, verbenone, and myrtenol are naturally occurring plant fragrance and flavorings. The preparation of these compounds by selective enzymatic oxidation of (+)-α-pinene, which is readily available in large quantities, could have applications in synthesis. The results also show that the protein engineering of P450cam for high selectivity of substrate oxidation is more difficult than achieving high substrate turnover rates because of the subtle and dynamic nature of enzyme - substrate interactions.
- Bell, Stephen G.,Chen, Xuehui,Sowden, Rebecca J.,Xu, Feng,Williams, Jennifer N.,Wong, Luet-Lok,Rao, Zihe
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p. 705 - 714
(2007/10/03)
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- Aerobic epoxidation of natural terpenes: Study of the catalytic activity of new Ru-1,2,4-triazepine compelxes
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Aerobic epoxidation of a range of natural terpenic olefines was carried out by using the triazepinic complexes [RuCl(TAZO)(p-cymene)] C1 and [Ru(TAZS)(p-cymene)]2 C2, recently prepared from [RuCl2(p-cymene)]2 and the corresponding 1,2,4-triazepines (HTAZO and H2TAZS). While, good similar stereoselectivity was observed for the two complexes, C1 was shown to be more effective and chemioselective.
- Fdil, Na?ma,Ait Itto, My Youssef,Ait Ali, Mustapha,Karim, Abdellah,Daran, Jean-Claude
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p. 8769 - 8771
(2007/10/03)
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- Manganese(III) porphyrin catalysts for the oxidation of terpene derivatives: A comparative study
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A comparative study involving four manganese(III) porphyrin catalysts combined with two different oxidants (sodium hypochlorite and potassium monopersulfate) has been performed in the epoxidation of three terpene derivatives. The catalytic oxidation of α-pinene produces selectively 100% of the epoxide or 65% of allylic oxidation products, only by modification of the substituents on the meso-positions of the metalloporphyrin catalyst. The catalytic oxidation of the 5-vinyl-2-norbornene is regio- and stereoselective, producing only the exo-2,3-epoxy-5-vinylnorbornane. With α-terpinene, a conjugated di-olefin, an oxidative dehydrogenation reaction was surprisingly observed, producing p-cymene as a major compound.
- Maraval, Valerie,Ancel, Jean-Erick,Meunier, Bernard
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p. 349 - 357
(2007/10/03)
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- Process for effecting allylic oxidation using dicarboxylic acid imides and chromium reagents
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A procedure for oxidizing organic compounds having allylic hydrogen atom(s) involving the steps of reactively contacting the organic compound with a combination of an N-hydroxy dicarboxylic acid imide and a chromium-containing oxidant. The reaction can conveniently be conducted under ambient temperature and pressure conditions, and is conveniently conducted in a co-solvent system of water and organic solvent(s).
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Page column 17-18
(2008/06/13)
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- Direct C-nitration of cyclic α,β-unsaturated oximes under the action of sodium nitrite and acetic acid in methanol
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Using a number of cyclic α,β-unsaturated oximes of the terpene series and some simplest model compounds as examples, unsaturated oximes bearing a hydrogen atom at the β-carbon atom were demonstrated to be converted into β-hydroxyiminonitroalkenes under the action of sodium nitrite and acetic acid in methanol. In the case of the introduction of an alkyl substituent at the terminal carbon atom of the diene C = C-C=NOH fragment, the reaction performed under the same conditions gave rise exclusively to conjugated ketone (a deoximation product).
- Chibiryaev,Denisov,Pyshnyi,Tkachev
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p. 1410 - 1418
(2007/10/03)
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- Engineering the haem monooxygenase cytochrome P450cam for monoterpene oxidation
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Monooxygenated terpenes are fine fragrance and flavouring chemicals, and active site mutants of the haem monooxygenase cytochrome P450cam which were designed to have improved complementarity between the substrate binding pocket and the monoterp
- Bell,Sowden,Wong
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p. 635 - 636
(2007/10/03)
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- New catalysts for the aerobic selective oxidation of hydrocarbons: Mn(III)- and Co(III)-containing molecular sieves for the epoxidation of alkenes
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Co(III) or Mn(III) ions that replace some 4 atom% of Al(III) sites in microporous aluminophosphate number 36 (AlPO-36) function as catalytically active centres for the production from benzaldehyde of acylperoxy radicals: these, in turn, in dry air (30 bar) convert cyclohexene, pinene, limonene and styrene to their corresponding epoxides and diols.
- Raja, Robert,Sankar, Gopinathan,Thomas, John Meurig
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p. 829 - 830
(2007/10/03)
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- Preparation of optically active apoverbenone and verbenone from nopinone by use of the sulfenylation-dehydrosulfenylation method. Stability and reactivity attributable to absolute configuration at the sulfur atom in sulfoxides
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Apoverbenone (4) and verbenone (5) in optically active forms are potentially useful compounds as the chiral source in enantioselective synthesis. Starting with (+)-nopinone (1), readily available from (-)-β-pinene, (+)-apoverbenone (4a) and (+)-verbenone (5a) were prepared in synthetically satisfactory overall yields, using commonly the sulfenylation-dehydrosulfenylation method directed toward construction of an enone function. This methodology could be applicable to preparation of their enantiomers (-)-4b and (-)-5b on starting with (-)-nopinone. While configuration of the phenylsulfinyl group in sulfoxides 10a, b, and 18a, b were assigned by their NMR spectra and NOE correlations, absolute configurations at the sulfur atom were performed by comparison in 1H NMR spectra with their homologues whose absolute configurations are well-defined, that is, lOa with 13a, lOb with 13b, 18a with 19b, and 18b with 19a. As a result, it was proved that, in 3-(phenylsulfinyl)nopinones, thermodynamic stability of isomers is dependent on absolute configuration at the sulfur center; that is, the frans-isomer 10a possesses an Rs-phenylsulfinyl group and the a's-isomer 10b possesses an Ss-phenylsulfinyl group, and it was proved that, in (4R)-4methyl-3-(phenylsulfinyl)nopinones, both as-isomers 18a, b are stable, irrelevant with absolute configurations at the sulfur atom. In elimination of phenylsulfenic acid from sulfoxides 10 and 18, the use of purified sulfoxides was essential, because the competing Pummerer reaction proceeded to give 3-(phenylthio)verbenone (11) as a byproduct, when acidic contaminants were present. The sulfoxides 10a, b and 18a provided smoothly 4a and 5a, respectively, in a syn elimination manner, whereas 18b gave a mixture of decomposed products as a major part, probably because of instability of 18b to heat as well as because of its conformational requirement.
- Kosugi, Hiroshi,Ku, Jaseung,Kato, Michiharu
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p. 6939 - 6946
(2007/10/03)
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- Neuroprotective (+) 3S, 4S cannabinoids with modified 5'-side chain
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The synthesis and evaluation of two novel cannabinoids belonging to the (+) 3S, 4S nonpsychotropic series are described. These derivatives bind to the NMDA receptor but have lower affinities than dexanabinol (HU-211), the series benchmark. The novel compounds protect neurons against MDA- induced toxicity in cortical cell cultures and have lower toxicity to host neurons than dexanabinol.
- Pop, Emil,Browne, Clinton E.,Nadler, Varda,Biegon, Anat,Brewster, Marcus E.
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p. 1553 - 1558
(2007/10/03)
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- Photocatalytic oxygenation of hydrocarbons with (tetraarylporphyrinato)iron(III) complexes and molecular oxygen. Comparison with microsomal cytochrome P-450 mediated oxygenation reactions
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Photocatalytic oxygenation of various alkenes with dioxygen and (5,10,15,20-tetraarylporphyrinato)iron(III) complexes yielded allylic oxygenation products and/or epoxides. The product composition was found to be influenced both by the nature of the used substrate and by the concentrations, as well as the axial ligands. Alkenes with strained carbon double bonds gave preferentially epoxides whereas mainly allylic oxygenation was observed for unstrained alkenes. The proposed reaction mechanisms involve the oxoiron(IV) porphyrinate (P)FeIV=O as the catalytically active species whose selectivity is related to that of the oxygenation of α-pinene with microsomal cytochromes P-450 and P-420 obtained from the yeast strain Torulopsis apicola. Oxygenation products observed with both systems give evidence for the occurrence of an oxoiron(IV) heme species in microsomal cytochrome P-450 mediated reactions. The enantio-, regio-, and chemoselectivities of the photooxygenation with iron(III) porphyrins and molecular oxygen are explained in terms of abstraction of an allylic hydrogen atom, catalyzed autoxidation and "direct" oxygen-transfer reactions.
- Weber,Hommel,Behling,Haufe,Hennig
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p. 2400 - 2408
(2007/10/02)
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- INTRODUCTION OF OXYGENATED FUNCTIONAL GROUPS INTO 3-CARENE AND 2-PINENE BY CULTURED CELLS
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The biotransformation of the monoterpene hydrocarbons 3-carene and 2-pinene by cell suspension cultures of Nicotiana tabacum and Catharanthus roseus was investigated.The cultures have the ability to regio- and enantioselectively introduce the oxygenated functional groups into the C=C double bond and the allylic positions of the substrates. - Key words: Nicotiana tabacum; Solanaceae; Catharanthus roseus; Apocyanaceae; cultured cells; biotransformation; epoxidation; hydroxylation; carene; pinene.
- Hirata, Toshifumi,Ikeda, Yoshihiro,Izumi, Shunsuke,Shimoda, Kei,Hamada, Hiroki,Kawamura, Toshinari
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p. 401 - 404
(2007/10/02)
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- Enantioselectivity in the Biotransformation of Mono- and Bicyclic Monoterpenoids with the Cultured Cells of Nicotiana tabacum
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The biotransformation of the enantiomeric pairs of p-menthane and bicyclo and heptane derivatives with the cultured cells of Nicotiana tabacum was investigated.It was found that (i) the cultured cells discriminate the enantiomers of p-menthan-2-ol and bicycloheptan-2-ol and bicycloheptan-3-ol derivatives, and enantioselectively convert these alcohols to the corresponding ketones, (ii) the cells reduce the carbonyl group of p-methan-2-one derivatives to a high extent, but not that of p-menthan-3-ones, and (iii) the cells discriminate the enantiomers of bicyclohept-2-en-4-one (verbenone) and enantioselectively reduce the C-C double bond of the (1S,5S)-enantiomer.
- Hamada, Hiroki
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p. 869 - 878
(2007/10/02)
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- Oxidation of Δ3-Carene and α-Pinene with Pyridinium Fluorochromate
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Oxidation of Δ3-carene and α-pinene with pyridinium fluorochromate (PFC) affords some novel oxidation products in acidic medium.The products have been characterised by spectral data (IR, PMR and mass).
- Varadarajan, R.,Dhar, R. K.
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p. 971 - 972
(2007/10/02)
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- AMINO ALCOHOLS IN PINANE SERIES. PART III. SYNTHESIS AND STEREOCHEMISTRY OF 3-AMINO-4-HYDROXY-CIS-PINANES AND THEIR DEUTERATED ANALOGS
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The synthesis of the title compounds based on reduction of unknown 3-hydroxyimino-cis-pinan-4-one (5) has been described.Stereochemistry of compounds obtained was established both on the basis of their 1H NMR spectra and 1H NMR spectra of their deuterated at C3 and C4 analogs.
- Burak, Krzysztof,Chabudzinski, Zenon
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p. 2015 - 2023
(2007/10/02)
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- Optical Rotatory Dispersion Studies. 128. Octant Contributions of Methyl Groups in 4-tert-Butylcyclohexanones
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A number of methyl-substituted 4-tert-butylcyclohexanones have been synthesized with high optical purity from naturally occuring chiral molecules of known absolute configuration.The circular dichroism spectra of these compounds were measured at both room temperature and 77 K in polar and nonpolar solvents, and empirical force field calculations were carried out to determine the energy difference between the chair and twist-boat conformations.Of particular interest was the discovery that the trans-3-methyl-4-tert-butylcyclohexanone (+)-4 exists mainly in the twist-boat form.In addition, the apparent antioctant behavior of the β-axial methyl group in compound (-)-5 at low temperature and in polar solvent is interpreted as arising form solvation of the molecule.
- Konopelski, Joseph P.,Sundararaman, P.,Barth, Guenter,Djerassi, Carl
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p. 2737 - 2745
(2007/10/02)
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