19902-08-0Relevant articles and documents
Temperature Controls Guest Uptake and Release from Zn4L4 Tetrahedra
Zhang, Dawei,Ronson, Tanya K.,Güryel, Songül,Thoburn, John D.,Wales, David J.,Nitschke, Jonathan R.
supporting information, p. 14534 - 14538 (2019/10/11)
We report the preparation of triazatruxene-faced tetrahedral cage 1, which exhibits two diastereomeric configurations (T1 and T2) that differ in the handedness of the ligand faces relative to that of the octahedrally coordinated metal centers. At lower temperatures, T1 is favored, whereas T2 predominates at higher temperatures. Host-guest studies show that T1 binds small aliphatic guests, whereas T2 binds larger aromatic molecules, with these changes in binding preference resulting from differences in cavity size and degree of enclosure. Thus, by a change in temperature the cage system can be triggered to eject one bound guest and take up another.
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 cyclohexene and α-pinene with O2-H 2 mixture in the presence of supported platinum or palladium catalysts
Kuznetsova,Kuznetsova,Kirillova,Pokrovskii,Detusheva,Ancel,Likholobov
, p. 1544 - 1551 (2007/10/03)
Oxidation of cyclohexene and α-pinene with an O2-H 2 mixture in the catalytic systems containing Pt or Pd and heteropoly compounds (HPC) was studied. The main oxidation products are epoxides, allyl alcohols, and ketones. The highest yield of the oxidation products was obtained in the presence of the platinum catalyst in combination with HPC PW11 or PW11Fe. The reaction mechanism was proposed. A relationship between the HPC composition and the nature of intermediates involved in oxidation was examined.
The first regio- and diastereoselective synthesis of homochiral perhydroimidazoisoxazoles via the 1,3-dipolar cycloaddition of imidazoline 3-oxides with (1S)-(-)-β-pinene
Coskun, Necdet,Tat, Fatma Tirli,Gueven, Oezden Oezel
, p. 1463 - 1467 (2007/10/03)
The 1,3-dipolar cycloaddition of imidazoline 3-oxides 1 with (1S)-(-)-β-pinene proceeds regio- and diastereoselectively to give homochiral perhydroimidazoisoxazole derivatives 3 in high yields in the cases of imidazoline 3-oxides 1a-e but in low yields in
Reactions of myrtenylzinc bromide with carbonyl compounds. Regio- and diastereo-selectivity
Aukrust, Inger Reidun,Nilsen, Nils Olav,Romming, Christian,Skattebol, Lars
, p. 385 - 390 (2007/10/03)
The organozinc reagent obtained from (-)-myrtenyl bromide and zinc powder in THF, under ultrasonic conditions, reacts rapidly with ketones and aldehydes furnishing homoallylic alcohols in high yields. The reactions were carried out both with preformed all
The First Stereoselective Palladium-Catalyzed Cyclocarbonylation of β,γ-Substituted Allylic Alcohols
Brunner, Melanie,Alper, Howard
, p. 7565 - 7568 (2007/10/03)
β,γ-Substituted allylic alcohols react with CO in the presence of catalytic quantities of palladium acetate and 1,4-bis(diphenylphosphino)butane affording α,β-substituted-γ-butyrolactones in 42-85% isolated yields. The complete stereoselectivity observed
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.
Isotopically Sensitive Branching as a Tool for Evaluating Multiple Product Formation by Monoterpene Cyclases
Wagschal, Kurt,Savage, Thomas J.,Croteau, Rodney
, p. 5933 - 5944 (2007/10/02)
The deuterated substrates geranyl pyrophosphate and geranyl pyrophosphate were employed to examine isotopically sensitive branching in the biosynthesis of monoterpene olefin isomers.By this method, (-)-α-pinene and (-)-β-pinene were shown to be synthesized via a common intermediate by a single cyclization enzyme from grand fir (Abies grandis), as were (-)-α-phellandrene and (-)-β-phellandrene by a single cyclase from lodgepole pine (Pinus contorta).Kinetic isotope effects were determined for the various deprotonations leading to the pinenes and phellandrenes.Key Words: Isotopically sensitive branching, monoterpene biosynthesis, monoterpene cyclase, resin biosynthesis, kinetic isotope effect.
SYNTHESIS WITH ORGANOBORANES. I. SYNTHESIS OF ALLYLIC DIETHYLBORANES AND B-ALLYLIC BORINANES VIA METALATION OF OLEFINS. CONTRATHERMODYNAMIC ISOMERIZATION OF OLEFINS
Zaidlewicz, Marek
, p. 139 - 146 (2007/10/02)
Allylic organopotassium compounds prepared by metalation of olefins with trimethylsilylmethylpotassium reacted with chlorodiethylborane and b-chloroborinane to give allylic diethylboranes and B-allylic borinanes, respectively.Hydrolysis of these organoboranes proceeding with allylic rearrangement leads to isomerized olefins.In this way, (E,Z)-2-pentene, (Z)-2-heptene, 1-methylcyclohexene and (+)-α-pinene were cleanly transformed into 1-pentene, 1-heptene, methylenecyclohexane and (+)-β-pinene, respectively.Stereochemistry of the addition of myrtenyldiethylborane toformaldehyde and 2-cyclohexenyldiethylborane to 4-t-butylcyclohexanone is described.