127-91-3Relevant articles and documents
Hydroboration of Terpenes. 9. A Simple Improved Procedure for Upgrading the Optical Purity of Commercially Available α- and β-Pinenes. Conversion of (+)-α-Pinene to (+)-β-Pinene via Hydroboration-Isomerisation.
Brown, Herbert C.,Joshi, Nawalkishore N.
, p. 4059 - 4062 (1988)
An improved method for the preparation of optically pure diisopinocampheylborane (Ipc2BH) from commercially available (+)- and (-)-α-pinene (91-92percent ee) is described.The procedure, which is based on selective incorporation of the major enantiomer of α-pinene in crystalline dialkylborane, is both simple and efficient.Treatment with benzaldehyde liberates the parent olefin in very high enantiomeric excess (>99.5percent).The intermediate Ipc2BH can be thermally isomerized (130 deg C, 12h) to dimyrtanylborane, which is readily converted into the otherwise inaccessible (+)-β-pinene (>99.5) percent ee).In the course of this study it was established that the optical purification of commercial (-)-β-pinene too can be easily achieved by the formation and recrystallisation of tri-cis-myrtanylborane.Thus, simple manipulations via hydroboration provide easy access to all four enantiomers of α- and β-pinenes in very high optical purity.
Thermal Reactions of B-Alkyl-9-borabicyclononane (9-BBN). Evidence for Unusually Facile Dehydroboration with B-Pinanyl-9-BBN
Midland, M. Mark,Petre, Janet E.,Zderic, Stephen A.,Kazubski, Aleksander
, p. 528 - 531 (1982)
B-Alkyl-9-BBN compounds undergo a slow olefin-alkyl group exchange when refluxed with an olefin in tetrahydrofuran.The half-life of the process for B-trans-2-methylcyclopentyl- and B-3-methyl-2-butyl-9-BBN is approximately 4 days.However, B-3-pinanyl-9-BBN undergoes an exceptionally rapid olefin-alkyl group exchange with a half-life of less than 10 h.Kinetic and competition experiments support a dehydroboration-hydroboration process.The isomerization of the B-3-pinanyl-9-BBN to B-myrtanyl-9-BBN, which one would expect to accompany such a facile dehydroboration, is not seen until 145 deg C.After 24 h at 165 deg C, the reaction reaches equilibrium with B-trans-myrtanyl-9-BBN as the major product.Treatment of this organoborane with benzaldehyde liberates the rare (+)-β-pinene.The facility with which B-3-pinanyl-9-BBN undergoes dehydroboration has important consequences for asymmetric reductions with this reagent.
Contra-thermodynamic Olefin Isomerization by Chain-Walking Hydroboration and Dehydroboration
Bloomer, Brandon,Butcher, Trevor W.,Ciccia, Nicodemo R.,Conk, Richard J.,Hanna, Steven,Hartwig, John F.
supporting information, p. 1005 - 1010 (2022/02/10)
We report a dehydroboration process that can be coupled with chain-walking hydroboration to create a one-pot, contra-thermodynamic, short-or long-range isomerization of internal olefins to terminal olefins. This dehydroboration occurs by a sequence comprising activation with a nucleophile, iodination, and base-promoted elimination. The isomerization proceeds at room temperature without the need for a fluoride base, and the substrate scope of this isomerization is expanded over those of previous isomerizations we have reported with silanes.
Acorenone B: AChE and BChE inhibitor as a major compound of the essential oil distilled from the ecuadorian species niphogeton dissecta (Benth.) J.F. macbr
Calva, James,Bec, Nicole,Gilardoni, Gianluca,Larroque, Christian,Cartuche, Luis,Bicchi, Carlo,Montesinos, José Vinicio
, (2017/11/16)
This study investigated the chemical composition, physical proprieties, biological activity, and enantiomeric analysis of the essential oil from the aerial parts of Niphogeton dissecta (culantrillo del cerro) from Ecuador, obtained by steam distillation. The qualitative and quantitative analysis of the essential oil was realized by gas chromatographic and spectroscopic techniques (GC-MS and GC-FID). Acorenone B was identified by GC-MS and NMR experiments. The enantiomeric distribution of some constituents has been assessed by enantio-GC through the use of a chiral cyclodextrin-based capillary column. We identified 41 components that accounted for 96.46% of the total analyzed, the major components were acorenone B (41.01%) and (E)-β-ocimene (29.64%). The enantiomeric ratio of (+)/(-)-β-pinene was 86.9:13.1, while the one of (+)/(-)-sabinene was 80.9:19.1. The essential oil showed a weak inhibitory activity, expressed as Minimal Inhibitory Concentration (MIC), against Enterococcus faecalis (MIC 10 mg/mL) and Staphylococcus aureus (MIC 5 mg/mL). Furthermore, it inhibited butyrylcholinesterase with an IC50 value of 11.5 μg/mL. Pure acorenone B showed inhibitory activity against both acetylcholinesterase and butyrylcholinesterase, with IC50 values of 40.8 μg/mL and 10.9 μg/mL, respectively.
Oxidation of α-pinene by atmospheric oxygen in the supercritical CO2-ethyl acetate system in the presence of Co(II) complexes
Anikeev,Ilina,Kurbakova,Nefedov,Volcho,Salakhutdinov
experimental part, p. 190 - 195 (2012/03/12)
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.
Weakening C-O bonds: Ti(III), a new reagent for alcohol deoxygenation and carbonyl coupling olefination
Dieguez, Horacio R.,Lopez, Armando,Domingo, Victoriano,Arteaga, Jesus F.,Dobado, Jose A.,Herrador, M. Mar,Quilez Del Moral, Jose F.,Barrero, Alejandro F.
supporting information; experimental part, p. 254 - 259 (2010/03/25)
Investigations detailed herein, including density functional theory (DFT) calculations, demonstrate that the formation of either alkoxy- or hydroxy-Ti(III) complexes considerably decreases the energy of activation for C-O bond homolysis. As a consequence of this observation, we described two new synthetic applications of Nugent's reagent in organic chemistry. The first of these applications is an one-step methodology for deoxygenation-reduction of alcohols, including benzylic and allylic alcohols and 1,2-dihydroxy compounds. Additionally, we have also proved that Ti(III) is capable of mediating carbonyl coupling-olefination. In this sense, and despite the fact that for over 35 years it has been widely accepted that either Ti(II) or Ti(0) was the active species in the reductive process of the McMurry reaction, the mechanistic evidence presented proves the involvement of Ti(III) pinacolates in the deoxygenation step of the herein described Nugent's reagent-mediated McMurry olefination. This observation sheds some light on probably one of the mechanistically more complex transformations in organic chemistry. Finally, we have also proved that both of these processes can be performed catalytically in Cp 2TiCl2 by using trimethylsilyl chloride (TMSCl) as the final oxygen trap.
ORALLY EFFECTIVE CANNABINOID ANALOGS
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Page/Page column 33-35, (2008/06/13)
The present invention relates to orally effective ligands of the peripheral cannabinoid thereof, receptor CB2 especially (+)-α pinene derivatives, and to pharmaceutical compositions thereof, which are useful for prevention, alleviation or treatment of autoimmune neurodegenerative disorders, in particular multiple sclerosis and associated symptoms. Methods of the invention are useful when the active ingredient is administered alone or in combination with existing therapeutic modalities. The compositions are administered by oral route.
HYDRONOPOL DERIVATIVES AS AGONISTS ON HUMAN ORL1 RECEPTORS
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Page/Page column 6, (2010/02/13)
The invention relates to a group of hydronopol derivatives which are agonists on human ORL1 (nociceptin) receptors. The invention also relates to the preparation of these compounds, to pharmaceutical compositions containing a pharmacologically active amount of at least one of these novel hydronopol derivatives as an active ingredient, as well as to the use of these pharmaceutical compositions for the treatment of disorders in which ORL1 receptors are involved. The invention relates to compounds of the general formula (1) wherein the symbols have the meanings as given in the description.
CHIRAL ORGANOSILICON HYDRIDES
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Page 30, (2010/11/30)
The invention provides a method for enantioselectively reducing a prochiral carbon centred radical having one or more electron donor groups attached directly to the central prochiral carbon atom of the radical, and/or attached to a carbon atom within 1 to 4 atoms of the central prochiral carbon atom, comprising treating said radical with an activated chiral non-racemic organosilicon hydride in the presence of a Lewis acid. The invention also provides a novel class of activated chiral non-racemic organosilicon hydrides.
Enantioselective synthesis of chiral liquid crystalline compounds from monoterpenes
Wang, Qian,Fan, Shi Yan,Wong, Henry N. C.,Li, Zhong,Fung, Bing M.,Twieg, Robert J.,Nguyen, Huu Tinh
, p. 619 - 638 (2007/10/02)
Chiral liquid crystalline compounds 1-9 have been synthesized enantioselectively from monoterpenes. The optical purities of (S)-(-)- and (R)-(+)-perillalcohol (16, 27), (S)-(-)- and (R)-(+)-1-pentyl-4-hydroxymethyl-1-cyclohexene (33, 34) and (2S,5S)-2-pentyl-5-hydroxymethyl-1-cyclohexanone (53) have been determined by 1H NMR analysis using chiral shift reagents. The mesomorphic phases and transition temperatures of compounds 2,3,5,6,7,8 and 9 have been characterized.
