Search results for "Alkoxy group"
showing 10 items of 108 documents
Alkoxy-, Acyloxy-, and Bromomethylation of Resorcinarenes
2004
Reaction of resorcinarene octols with tris-hydroxymethylmethylamine (TRIS), formaldehyde, and alcohols results in tetraalkoxymethylation of the resorcinol rings. Harsh acylation of aminomethylated resorcinarenes with acid anhydrides leads to the complete acylation of eight hydroxyls and substitution of the amino versus acyloxy groups. Acyloxymethylated resorcinarene 6b can be transformed into a tetrabromomethylated derivative 7 through the reaction with HBr in acetic acid.
[Cu(P^P)(N^N)][PF6] compounds with bis(phosphane) and 6-alkoxy, 6-alkylthio, 6-phenyloxy and 6-phenylthio-substituted 2,2'-bipyridine ligands for lig…
2018
We report a series of [Cu(P^P)(N^N)][PF6] complexes with P^P = bis(2-(diphenylphosphino)phenyl)ether (POP) or 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (xantphos) and N^N = 6-methoxy-2,2′-bipyridine (MeObpy), 6-ethoxy-2,2′-bipyridine (EtObpy), 6-phenyloxy-2,2′-bipyridine (PhObpy), 6-methylthio-2,2′-bipyridine (MeSbpy), 6-ethylthio-2,2′-bipyridine (EtSbpy) and 6-phenylthio-2,2′-bipyridine (PhSbpy). The single crystal structures of all twelve compounds have been determined and confirm chelating modes for each N^N and P^P ligand, and a distorted tetrahedral geometry for copper(I). For the xantphos-containing complexes, the asymmetrical bpy ligand is arranged with the 6-substituent lying …
Combining Neopentyllithium with Potassium tert-Butoxide: Formation of an Alkane-Soluble Lochmann-Schlosser Superbase.
2016
Mixtures of alkyllithium and heavier alkali-metal alkoxides are often used to form alkyl compounds of heavier alkali metals, but these mixtures are also known for their high reactivity in deprotonative metalation reactions. These organometallic mixtures are often called LiC-KOR superbases, but despite many efforts their constitution remains unknown. Herein we present mixed alkali-metal alkyl/alkoxy compounds produced by reaction of neopentyllithium with potassium tert-butoxide. The key to success was the good solubility and temperature-stability of neopentyl alkali-metal compounds, leading to hexane-soluble mixtures, which allowed handling at ambient temperatures and isolation by crystalliz…
Insights into the Synthesis and the Solution Behavior ofmeso-Aryloxy- and Alkoxy-Substituted Porphyrins
2015
meso-RO-appended (R = alkyl, aryl) porphyrins bearing one or two OR substituents at the tetrapyrrolic macrocycle were synthesized in good yields from 5,15-dibromo-10,20-diphenylporphyrins 2H(Br2DPP), Ni(Br2DPP) and Zn(Br2DPP) using an SNAr reaction. By varying the solvent, the base, the temperature, and the time of the reaction, the optimum conditions were established, and the selective introduction of one or two meso-RO substituents at the periphery of the macrocycle was achieved. Moreover, monofunctionalization of Ni(Br2DPP) according to an SNAr reaction was used as a key step for the synthesis of rarely explored unsymmetrical porphyrinyl alkyl ethers. 1H NMR studies of these ethers in CD…
Photochemical versus aluminium chloride-catalyzed fries rearrangement of aryl hydrogen succinates. synthesis of 2(3H)-furanones
1989
The photochemical and aluminium chloride-catalyzed Fries rearrangement of a series of aryl hydrogen succinates3 a–f to the corresponding 4-oxoacids1 a–f are compared. Both approaches are complementary: the photochemical process is more general and becomes the method of choice for the succinoylation of phenols supporting alkoxy or hydroxy substituents, while the classical rearrangement is superior in the presence of alkyl or halogen substituents. These results are applied to the preparation of the 2(3H)-furanones2 a–f.
Anthracene Based Conjugated Polymers: Correlation between π−π-Stacking Ability, Photophysical Properties, Charge Carrier Mobility, and Photovoltaic P…
2010
This article reports on the synthesis, characterization and properties of a series of anthracene−containing poly(p-phenylene-ethynylene)-alt-poly(p-phenylene-vinylene)s (PPE−PPV) copolymers with general constitutional unit (Ph−C≡C−Anthr−C≡C−Ph−CH═CH−Ph−CH═CH−)n denoted AnE-PV. Solely linear (AnE-PVaa, -ad, -ae) and solely branched (AnE-PVbb) as well as mixed linear and branched (AnE-PVab, -ac, -ba, -cc) alkoxy side chains were grafted to the backbone in order to tune the π−π-stacking ability of the materials. It has been possible to establish a correlation between π−π-stacking ability, absorptive behavior, charge carrier mobility, solar cell active layer nanoscale morphology and resulting p…
Intercorrelation between Structural Ordering and Emission Properties in Photoconducting Polymers
2009
We investigated the structural properties of anthracene containing poly(p-phenylene−ethynylene)-alt-poly(p-phenylene−vinylene) polymers with general constitutional unit: (−Ph−C≡C−Anthr−C≡C−Ph−CH═CH−Ph−CH═CH−)n by means of wide-angle X-ray scattering and fluorescence spectroscopy. Interchain interactions were systematically modified by decorating the conjugated polymer backbone with linear or branched or combinations of linear and branched alkoxy side chains. Special emphasis is taken on an evaluation method for fiber scattering spectra that allows the deduction of important structural details of polymer materials with limited degree of order. These include positional correlations along the …
Towards the Next Generation of Lochmann-Schlosser Superbases: A Potassium Neopentyl/Alkoxy Aggregate used in the Tetra-Functionalization of Ferrocene
2018
Lochmann-Schlosser superbases are formed by mixing alkyllithium with potassium alkoxides. These reagents could prove their synthetic usefulness and reliability in many reactions over five decades. However, despite many efforts, the real source of the exceptional reactivity remained a secret. The seemingly manageable system of four components (lithium, potassium atoms, alkyl groups, and alkoxy groups) and their interaction is obscured by poor solubility and fierce reactivity. Recent progress was achieved by using neopentyllithium, leading to alkane-soluble aggregates with varying lithium/potassium content and a flexible alkyl/alkoxy ratio. Herein, we isolated two new alkane-soluble alkyl/alk…
Radiosynthesis of (±)-(2-((4-(2-[18F]fluoro-ethoxy)phenyl)bis(4-methoxy-phenyl)methoxy)ethylpiperidine-3-carboxylic acid: a potential GAT-3 PET ligan…
2001
A dysfunction of GABAergic neurotransmission is related to diseases such as epilepsy, Huntington-disease and Parkinson-syndrome. A new 18F-fluorine labelled GABA transporter ligand for the GABA-transporter subtype GAT-3 was developed which may allow the in vivo visualisation of GABAergic neurotransmission. The precursors ethyl (2-(4-hydroxyphenyl)bis(4-methoxyphenyl)-methoxy)ethyl)-piperidine-3-carboxylate and ethyl(2-((4-(2-tosylethoxy)phenyl)-bis(4-methoxyphenyl)-methoxy) ethyl)-piperidine3-carboxylate were synthesised and labelled by the use of 2-[18F]fluoroethyltosylate or [18F]fluoride. Subsequent cleavage of the ester moiety gave the final product (±)-(2-((4-(2-[18F]fluoroethoxy)pheny…
Carbazole synthesisviaanin situtrapping strategy with indolyl enol ethers
1994
Indolyl enol ethers, generated from the alkoxy(indolyl)carbenium tetra- fluoroborates (1) by treatment with sodium hydride, can be trapped with dimethyl acetylenedicarboxylate or N-phenylmaleimide to furnish the se- lectively functionalized carbazoles (3), (4), (5), (9), (10), and (13). In addition, the biaryl derivatives (6) and (11) are produced by a ring- opening reaction of the primarily formed Diels-Alder adduct. In the case of the biaryl derivative (6), an X-ray crystal structure analysis yields valuable information on constitutions and configurations in the biaryl series. The phenomenon of atropisomerism is discussed for this compound