Search results for "HILIC"
showing 10 items of 745 documents
Enantioselective zinc/BINOL-catalysed alkynylation of aldimines generated in situ from α-amido sulfones.
2012
Chiral nonracemic N-Cbz-protected propargylic amines have been prepared by the addition of terminal alkynes to imines generated in situ from α-amido sulfones in the presence of diethylzinc and BINOL-type ligands as catalysts. The reactions give good yields and high enantioselectivities (ee values up to 95 %) for a good number of aromatic and heteroaromatic α-amido sulfones and alkynes.
Synthesis of Fluorinated Indazoles Through ANRORC-Like Rearrangement of 1,2,4-Oxadiazoles with Hydrazine.
2006
A series of 6-substituted fluorinated indazoles has been obtained through an ANRORC-like rearrangement (Addition of Nucleophile, Ring-Opening and Ring-Closure) of 5-tetrafluorophenyl-1,2,4-oxadiazoles with hydrazine. The initial addition of the bidentate nucleophile to the electrophilic C(5) of the 1,2,4-oxadiazole ring, followed by ring opening and ring closure, leads to the formation of fluorinated indazoles in high yield under mild experimental conditions. Functionalization of the C(6) in the final indazole nucleus was preliminarily achieved through a nucleophilic aromatic substitution on the starting 5-pentafluorophenyl-1,2,4-oxadiazole.
Nucleophilic reactions in the indole series: displacement of bromine under phase transfer catalysis
2008
A novel synthetic approach for the synthesis of 3-substituted indoles by nucleophilic substitution of 3-bromo derivatives under phase transfer catalysis (PTC) was reported.
Profile and molecular modeling of 3-(indole-3-yl)-4-(3,4,5-trimethoxyphenyl)-1 H-pyrrole-2,5-dione (1) as a highly selective VEGF-R2/3 inhibitor.
2006
We report on selectivity profiling of 1 in a panel of 20 protein kinases and molecular modeling indicating 1 to be highly active and selective for VEGF-R2/3. Sequence alignment analysis and detailed insights into the ATP binding pockets of targeted protein kinases from the panel result in a unique structural architecture of VEGF-R2 mainly caused by the hydrophobic pocket I, determining the molecular basis for activity and selectivity of 1.
Polycondensed nitrogen heterocycles. Part13. Pyrrolo[3,2-b]indole by intramolecular nucleophilic substitution reaction in the pyrrole series
1984
An intramolecular nucleophilic substitution in the pyrrole series has been generalized. The behaviour of nitro, chlorine, bromine and iodine as leaving groups towards the nucleophilic amino group was observed. An acid catalyzed mechanism has been proposed.
Synthesis of Functionalized Indoles with a Trifluoromethy-Substituted Stereogenic Tertiary Carbon Atom Through an Enantioselective Friedel-Crafts Alk…
2010
[EN] Chiral complexes of BINOL-based ligands with zirconium tert-butoxide catalyze the Friedel-Crafts alkylation reaction of indoles with beta-trifluoromethyl-alpha,beta-unsaturated ketones to give functionalized indoles with an asymmetric tertiary carbon center attached to a trifluoromethyl group. The reaction can be applied to a large number of substituted alpha-trifluoromethyl enones and substituted indoles. The expected products were obtained with good yields and ees of up to 99%.
Hsp60 chaperonopathies and chaperonotherapy: targets and agents
2014
Hsp60 (Cpn60) assembles into a tetradecamer that interacts with the co-chaperonin Hsp10 (Cpn10) to assist client polypeptides to fold, but it also has other roles, including participation in pathogenic mechanisms.Hsp60 chaperonopathies are pathological conditions, inherited or acquired, in which the chaperone plays a determinant etiologic-pathogenic role. These diseases justify selection of Hsp60 as a target for developing agents that interfere with its pathogenic effects. We provide information on how to proceed.The information available encourages the development of ways to improve Hsp60 activity (positive chaperonotherapy) when deficient or to block it (negative chaperonotherapy) when pa…
6-Thiopurine complexes of organotin(IV) moieties. Synthesis and structural characterization by infrared and Mössbauer spectroscopy
1982
Abstract The novel complexes Me3Sn(6-TP−1) and Bun2Sn(6-TP−1)2, where 6-TP−1 is the mono-anion of 6-thiopurine, have been synthesized. The sites of stannylation of 6-TP have been inferred from the known directions of electrophilic substitution reactions of 6-TP itself. The compounds have been characterized by infrared and Mossbauer spectroscopy. A solid state polymeric structure has been proposed for Me3Sn(6-TP−1), where planar SnC3 skeletons are bridged by 6-TP−1 (thione tautomer) axially bound to Sn through N(3) and N(1) atoms. For Bun2Sn(6-TP−1)2, a molecular structure has been advanced, with the ‘aromatic’ ligand anions chelating Sn by S-N(7) atoms.
Preparation, Properties, and Reactivity of (Aminoferrocenyl)(ferrocenyl)carbene(pentacarbonyl)chromium(0) as Bulky Isolobal Trimetallo-amide
2015
Nucleophilic substitution of the ethoxy substituent in the Fischer carbene complex (ethoxy)(ferrocenyl)carbene(pentacarbonyl)chromium(0) (1) by ferrocenyl amide [Fc-NH]– [2-H]– gives the hetero trimetallic complex (aminoferrocenyl)(ferrocenyl)carbene (pentacarbonyl)chromium(0) (3). As the Cr(CO)5 fragment is isolobal to oxygen or sulfur 3 can be viewed as an isolobal metallo analogue to diferrocenylamide (Fc)(FcNH)C=O (4) and diferrocenylthioamide (Fc)(FcNH)C=S (5). The impact of the formal replacement of O/S by Cr(CO)5 in 3 is studied with respect to steric and electronic consequences as well as reactivity by spectroscopic, diffraction, electrochemical and theoretical methods.
Zum Mechanismus der Inden‐Bildung durch Friedel‐Crafts‐Cycloalkenylierung
1972
α,β-Ungesattigte Aldehyde reagieren mit Benzol unter Friedel-Crafts-Bedingungen zu Indenen. Mittels 14C- und 2H-indizierten Verbindungen werden die reversible, nucleophile Addition von Benzol an Zimtaldehyd sowie die 1.3-Wasserstoff-Verschiebung im Crotonaldehyd beim Ringschlus nachgewiesen. On the Mechanism of the Indene Formation by Friedel-Crafts Cycloalkenylation α,β-Unsaturated aldehydes were condensed with benzene in a Friedel-Crafts type reaction to give indenes. With the aid of 14C- and 2H-labelled compounds both the reversible nucleophilic addition of benzene to cinnamaldehyde and the 1.3-hydrogen shift in the cycloalkenylation of crotonaldehyde are examined.