Search results for "Catalysis"

Diels-Alder reactions of 1-phenylpyrano[3,4-b]indol-3-ones with alkynes: New functionalized carbazoles

1990

3-Indolylalkanoic acids 2 react with benzoic acid anhydride under catalysis of Et2O - ZnCl2 and mild conditions to furnish the 1-phenyl-substituted pyrano[3,4-b]indol-3-ones 1c, 1d, and 3a, 3b. Products 1c, 1d, and 3b may be converted into the novel functionalized carbazoles 4 and 5 by reaction with acceptor-substituted alkynes.

Synthetic Application of Homogeneous Charge Transfer Catalysis in the Electrocarboxylation of Benzyl Halides

1998

The results of an investigation on the performances of some outer sphere electron transfer homogeneous catalysts in the electrocarboxylation of 1-(p-isobutyl-phenyl)-1-chloroethane to 2-(p-isobutyl-phenyl)-propionic acid (Ibuprofen), using as catalysts the esters of benzoic and o-, m-, and p-phtalic acids, are reported. The performances of the catalysts are evaluated on the basis of the following parameters: faradic yields of the carboxylation and decomposition of the catalyst. The performances of dimethylisophtalate have been examined in greater detail. The rate of decomposition of the catalyst is related to the molar ratio [halide]/[catalyst].

A Carbohydrate-Based Julia–Kocienski Reagent for Syntheses of Chain-Extended and C-Linked Saccharides

2014

The carbohydrate-derived Julia–Kocienski reagent 2-{[(3aS,4S,6R,6aR)-6-methoxy-2,2-dimethyltetrahydrofuro[3,4-d][1,3]dioxol-4-yl]methylsulfonyl}-1,3-benzothiazole (6) was prepared from d -ribose and investigated in the eponymous olefination. The base-promoted generation of the Julia anion induced a rearrangement­ to the corresponding l -lyxose epimer 2-{[(3aS,4R,6R,6aR)-6-methoxy-2,2-dimethyltetrahydrofuro[3,4-d][1,3]dioxol-4-yl]methylsulfonyl}-1,3-benzothiazole (12), which reacted readily with aldehydes and with a gluconolactone. The latter reaction furnished an exo-glycal-linked C-diglycoside.

Ionic Liquids in Biphasic Ethylene Polymerisation

2011

Over the past several years there has been a considerable increase in the interest of ionic liquids as versatile reaction media for a wide variety of synthetic processes. The popularity of ionic liquids has been related primarily to their unique physical and chemical properties, which can be tailored by the judicious selection of cations and anions. These properties make it possible to use ionic liquids as solvents for many organic, inorganic, and organometallic compounds, including catalysts and co-catalysts, for various types of reactions. In particular, the polar but weakly coordinating character of ionic liquids enables them to be applied as mediums in catalysis, to immobilize various k…

Rational Design of an Enneanuclear Copper(II) Complex with a Metallacyclophane Core

2004

An approach to polymer-supported triplet benzophenone photocatalysts. Application to sustainable photocatalysis of an α-diazocarbonyl compound

2013

Covalent immobilization of 4-hydroxybenzophenone on Merrifield resins affords new heterogeneous polymeric triplet photocatalysts. Their successful application in the intramolecular triplet-sensitized photolysis of a α-diazo β-keto ester has been achieved under sustainable criteria. Remarkably, the simple recovery and reuse for up to five sequential applications have been performed, although resulting in a slightly decreasing activity.

Frontispiece: Positive Allosteric Control of Guests Encapsulation by Metal Binding to Covalent Porphyrin Cages

2019

ChemInform Abstract: Diels-Alder Reactions of 1-Phenylpyrano(3,4-b)indol-3-ones with Alkynes: New Functionalized Carbazoles.

1990

3-Indolylalkanoic acids 2 react with benzoic acid anhydride under catalysis of Et2O - ZnCl2 and mild conditions to furnish the 1-phenyl-substituted pyrano[3,4-b]indol-3-ones 1c, 1d, and 3a, 3b. Products 1c, 1d, and 3b may be converted into the novel functionalized carbazoles 4 and 5 by reaction with acceptor-substituted alkynes.

Pyrene-benzoylthiophene exciplexes as selective catalysts for the [2+2] cycloaddition between cyclohexadiene and styrenes.

2007

Efficient intramolecular fluorescence quenching in pyrene−benzoylthiophene systems leads to formation of exciplexes. These species interact with 1,3-cyclohexadiene (or styrenes), leading to reactive excited triplexes. The overall process affords [2+2] cross-cycloadducts with an average yield of 57%.

Metal-organic frameworks-based catalysts for biomass valorization

2020

Abstract The objective of this chapter is to review the most promising metal-organic framework (MOF) catalysts in biomass valorization processes in the bulk and fine chemical industries. Either bulk metal-organic frameworks, encapsulated catalytic species in MOFs, or MOF-derived catalysts are revised in terms of activity, selectivity, and stability for biomass valorization applications. The work revised here is focused on the transformation of lignocellulose biomass through purely chemical pathways. In the first part of the chapter, the few studies of cellulose hydrolysis into monosaccharides reported are commented, since this crucial first step in the valorization of hemicellulose is expec…