Synthesis and utilization of functionalized polystyrene resins

Co-polymerised 4-bromopolystyrene has been converted to a range of polymer-supported reagents and scavengers by bromine-magnesium exchange using Oshima's trialkylmagnesate complex followed by quenching with a variety of electrophiles. Mitsunobu, halogenation and Wittig reactions, were explored to assess the utility of the resins for target oriented and diversity oriented synthesis.     

Effects of Different Eelectron-withdrawing Moieties on the General Photoelectric Properties of Fluorene-based Dimers

Here, 9,9,9'-tris(4-butoxyphenyl)-9H-9'H-2,2'-difluorene(DF) was synthesized as a reference for compa-rison, and diphenyl sulfone and triphenylphosphine oxygen were introduced to the 9-position of fluorene through a C-H coupling reaction to produce two fluorene-based oligomers 9',9'-[sulfonylbis(4,1-phenylene)]bis[9,9,9'-tris-(4-butoxyphenyl)-9H,9'H-2,2'-bifluorene](DF)₂SO₂ and phenylbis(4-{9,9',9'-tris(4-butoxyphenyl)-9H,9'H-[2,2'-bif-luorene]-9-yl}phenyl)phosphine oxide[(DF)₂PO]. Solid powders of all the three compounds exhibit excellent thermal stability with thermal temperature at 5% mass loss of 375, 429 and 383℃ for (DF)₂SO₂, (DF)₂PO and DF. In addition, owing to the distorted molecular structure and weak electron-absorbing ability of the acceptor, (DF)₂SO₂ and (DF)₂PO do not have obvious intramolecular charge transfer characteristics, and exhibit stable localized 394 nm/375 nm fluorescence emission peaks in different polar solvents. The absolute luminescence quantum efficiencies of (DF)₂SO₂, (DF)₂PO and DF solid powders are 20.83%, 10.03% and 59.46%. Compound DF has the highest quantum yield as an electron donor. The chromaticity coordinates of the blue OLED devices based on DF and DF₂SO₂ fabricated by solution spin coating were (0.19, 0.10) and (0.19, 0.11), which were closest to the deep blue region, and the corresponding maximum external quantum efficiencies are 1.45% and 0.87%, respectively, which are higher than that of (DF)₂PO(0.25%) and consistent with the difference in the solid-state quantum efficiency between them.     

Synthesis and characterization of O,O′-dialkyl and alkylene dithiophosphates of thorium(IV) and their adducts with nitrogen and phosphorus donors

Thorium(IV) tetrakis(dithiophosphates), [Th{S₂P(OR)₂}₄] (where R?=?–CH₂CH₂CH₃ or –C₆H₅) and [Th{S₂PO₂G}₄] [where G?=?–C(CH₃)₂CH₂CH(CH₃)–, –CH₂C(CH₃)₂CH₂–, –C(CH₃)₂C(CH₃)₂– and –CH₂CH₂CH(CH₃)–] were prepared in methanolic solution of Th(NO₃)₄???6H₂O and ammonium dithiophosphates. Adducts of the type [Th{S₂P(OR)₂}₄???nL] and [Th{S₂PO₂G}₄???nL] [where n?=?1, L?=?N₂C₁₀H₈ or N₂C₁₂H₈ and n?=?2, L?=?P(C₆H₅)₃] were prepared by the reaction of thorium(IV) tetrakis(dithiophosphates) and nitrogen or phosphorus donors in benzene. These newly synthesised derivatives have been characterized by elemental analyses, molecular weights, IR, ¹H and ³¹P NMR spectral measurements. Coordination numbers of eight and ten are suggested for thorium(IV) in these derivatives.     

A Simple Synthesis of Stable Phosphoranes Derived from Imides or Acetanilide Derivatives

Stable crystalline phosphorus ylides are obtained in excellent yields from the 1:1:1 addition reaction between triphenylphosphine, dialkyl acetylenedicarboxylates, and strong NH-acids, such as acetanilide, 4-methylacetanilide, 2-cyanoacetanilide, 4-bromoacetanilide, 4-methoxyacetanilide, succinimide, malimide, or phthalimide. These stabilized phosphoranes exist as a mixture of two geometrical isomers as a result of restricted rotation around the carbon-carbon partial double bond resulting from conjugation of the ylide moiety with the adjacent carbonyl group.     

Synthesis and structural characterization of heteroleptic Cu(I) complexes with α-diimines derived from pyridinyliminobenzoic acids

The synthesis and molecular and electronic structure of heteroleptic univalent copper compounds [Cu(L)(PPh₃)X] are reported where X is a halide and L represents 3-pyridinylimino, 4-pyridinylimino or 3,5-dipyridinylimino-substituted benzoic acid, hereafter abbreviated as L1, L2, and L3, respectively. The crystal structures of two iodide and one bromide complexes are described. All compounds are hydrogen-bonded dimers. The electronic excitation spectra of the compounds are dominated by intraligand bands of ligands while characteristic MLCT transitions are observed at 430–480?nm. No emission is observed from the compounds either in the solid state or in solution; on the contrary a photodecomposition is observed resulting in triphenylphosphane ligand elimination and formation of halogen-bridged dimmers.     

Synthesis of β,β‘-Difluorinated and β,β’-F-Dialkylated Acetals

Using the phase transfer catalysis technique, a series of fluorinated acetals has been prepared, in basic medium, by action of dicholromethane on 2-mononfluorinated alcohols or 1-F-alkyl 2-fluoroethanols. The identification of these new acetals has been achived by the study cf their ¹H, 19F NMR and their mass spectra.     

Silica Gel Catalyzed Conversion of Dialkyl 2-(2-Hydroxy-1-naphthyl)-3-(1,1,1-triphenyl-λ 5 -phosphanylidene) Succinates to Alkyl 3-Oxo-3 H -benzo[ f ]chromene-1-carboxylates in Solvent-free Conditions

Protonation of the highly reactive 1:1 intermediates produced in the reaction between triphenylphosphine and dialkyl acetylenedicarboxylates by 2-hydroxynaphthalene leads to vinyltriphenylphosphonium salts, which undergo aromatic electrophilic substitution reaction with conjugate base to produce dialkyl 2-(1-hydroxy-2-naphthyl)-3-(1,1,1-triphenyl- u 5 -phosphanylidene) succinates. Silica gel was found to catalyze conversion of dialkyl 2-(1-hydroxy-2-naphthyl)-3-(1,1,1-triphenyl- u 5 -phosphanylidene) succinates to alkyl 3-oxo-3H-benzo[f]chromene-1-carboxylates in solvent-free conditions at 60°;C in fairly good yields.     

Silica Gel Catalyzed Stereoselective Conversion of Dialkyl 2-(3-acetyl-4-hydroxy-1-naphthyl)-3-(triphenylphosphoranylidene) butanedioates to Dialkyl 2-(3-acetyl-4-hydroxy-1-naphthyl)-2-butenedioates in Solvent-Free Conditions

Protonation of the highly reactive 1:1 intermediates, produced in the reaction between triphenylphosphine and dialkyl acetylenedicarboxylates, by 1-hydroxy-2-acetonaphthone leads to vinyltriphenylphosphonium salts, which undergo aromatic electrophilic substitution reaction with conjugate base to produce dialkyl 2-(3-acetyl-4-hydroxy-1-naphthyl)-3-(triphenylphosphoranylidene) butanedioates. Silica gel was found to catalyze conversion of dialkyl 2-(3-acetyl-4-hydroxy-1-naphthyl)-3-(triphenylphosphoranylidene) butanedioates to dialkyl 2-(3-acetyl-4-hydroxy-1-naphthyl)-2-butenedioates in solvent-free conditions at 90°;C in fairly good yields.     

One–Pot Synthesis of β,γ-Unsaturated γ-Lactone Phosphorus Yildes using 2-Nitro Trans-Cinnamaldehyde and Acetylenic Esters in the Presence of Triphenylphosphine

Abstract

Three-component reaction of triphenylphosphine and 2-nitro trans-cinnamaldehyde with dialkyl acetylenedicarboxylate leads to β,γ-unsaturated γ-lactone phosphorus ylides in moderate yields. The reactions of 2-nitro trans-cinnamaldehyde with alkyl propiolates in the presence of triphenylphosphine produce 2H-pyran derivatives in moderate yields without the formation of any γ-lactone derivatives.     

An Efficient Synthesis of Stable Phosphorus Ylides Derived from Hydantoin and 5,5-dialkylhydantoins

Stable crystalline phosphorus ylides are obtained in excellent yields from the 1:1:1 addition reaction between triphenylphosphine and dialkyl acetylenedicarboxylates in the presence of strong NH-acids, such as hydantoin and 5,5-dialkylhydantoins. These stable ylides exist in solution as a mixture of two geometrical isomers as a result of restricted rotation around the carbon-carbon partial double bond resulting from conjugation of the ylide moiety with the adjacent carbonyl group.