Presence Of Sodium Tert-butoxide Research Articles

Synthesis and characterization of amphiphilic Poly(2-hydroxyethyl acrylate-g-α-Methyl-β-Alanine) by Nitroxide-Mediated Polymerization Using “grafting through” approach

Oligomeric poly(α-methyl-β-alanine)with vinyl end-group (PmBA) was synthesized via base-catalyzed hydrogen-transfer polymerization (HTP) of molten methacrylamide (MAm) in the presence of sodium tert-butoxide (t-BuONa). The PmBA was used as a comonomer in the synthesis of amphiphilic poly(2-hydroxyethyl acrylate-g-α-methyl-β-alanine) (PHEA-g-PmBA)via nitroxide-mediated polymerization (NMP)and "grafting through" approach.The graft copolymer formation was confirmed byproton nuclear magnetic resonancespectroscopy (1H-NMR), Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and static light scattering (SLS)measurements. Thermogravimetric analysis of the amphiphilicPHEA-g-PmBAexhibited a multi-step decomposition curve corresponding to the α-methyl-β-alanine and the 2-hydroxyethyl acrylate blocks at about 306, 369, and 403 °C.DSC curve of the copolymer has a baseline shift at −12.87 °C attributed to the glass transition temperature. SLS analysis of the final product resulted in a weight average molecular weight of 83.6 kDa. The spectroscopic and thermal analyses proved that amphiphilicPHEA-g-PmBA was successfully synthesized through HTP and NMP.

NEW ROUTE FOR THE SYNTHESES OF SOME NOVEL DERIVATIVES OF 3-ARYL BENZO[d] THIAZOLE-2(3H)-IMINE FROM HIGH SUBSTITUTED THIOUREAS

We have developed herein a new approach to diverse synthesis of novel derivatives of 3-Aryl benzo[d]thiazole-2(3H)-imines (3a-g), by a two-component reaction between diazonium salt (2) and various synthesized N-acyl-N'-aryl thioureas (1a-g), in the presence of sodium tert butoxide as strong base. Finally, it resulted in the production of the desired product with a moderate yield. The chemical structures of these synthesized compounds were confirmed by various physico-chemical methods viz. FT-IR, 1H-NMR, 13C-NMR and elemental analysis.

Environmentally Benign Strategy for Arylation of Nitronyl Nitroxide Using a Non-Transition Metal Nucleophile.

We have developed a method for the arylation of nitronyl nitroxide without using its transition metal complex as a nucleophile. Various nitronyl nitroxide-substituted π-electronic compounds can be obtained from the parent nitronyl nitroxide and the corresponding aryl iodides using a combination of zero-valent palladium catalysts and a 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl ligand in the presence of sodium tert-butoxide. The utility of the method has been demonstrated by the direct synthesis of open-shell compounds with giant π-electronic systems, such as 10P.

Chemoselective Coupling of 1,1-Bis[(pinacolato)boryl]alkanes for the Transition-Metal-Free Borylation of Aryl and Vinyl Halides: A Combined Experimental and Theoretical Investigation

A new transition-metal-free borylation of aryl and vinyl halides using 1,1-bis[(pinacolato)boryl]alkanes as boron sources is described. In this transformation one of the boron groups from 1,1-bis[(pinacolato)boryl]alkanes is selectively transferred to aryl and vinyl halides in the presence of sodium tert-butoxide as the only activator to form organoboronate esters. Under the developed borylation conditions, a broad range of organohalides are borylated with excellent chemoselectivity and functional group compatibility, thus offering a rare example of a transition-metal-free borylation protocol. Experimental and theoretical studies have been performed to elucidate the reaction mechanism, revealing the unusual formation of Lewis acid/base adduct between organohalides and α-borylcarbanion, generated in situ from the reaction of 1,1-bis[(pinacolato)boryl]alkanes with an alkoxide base, to facilitate the borylation reactions.

ChemInform Abstract: Nickel‐Catalyzed Coupling of Fluoroarenes and Amines.

The combination of bis(cyclooctadiene)nickel [Ni(COD)2] and 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene hydrochloride (IPr⋅HCl) effectively catalyzes coupling of fluoroarenes with amines in the presence of sodium tert-butoxide (t-BuONa). Activated, unactivated and deactivated fluoroarenes as well as fluoropyridines can react with cyclic or acyclic aliphatic amines. The reactions tolerate various functional groups in the fluorides including PhC(O), C(O)NEt2, CF3, OMe and vinyl groups.

An Efficient Catalyst System for the Synthesis of N-(p-benzoylaminoaryl)- N'-Boc Piperazines Under Microwave Conditions

We have developed a new combination of catalyst system for the synthesis of N-(p-benzoylaminoaryl)-N'-Boc piperazines under microwave conditions (Biotage, 300 Watt) in the presence of sodium tert-butoxide and in DMF. The catalyst and ligand used are Tris (dibenzylideneacetone) dipalladium(0) and 2-Dicyclohexylphosphino-2-(N,Ndimethylamino) biphenyl (Dave Phos) respectively, the desired N-(p-benzoylaminoaryl)-N'-Boc Piperazines was obtained in good yields (80-92%).

ChemInform Abstract: A Novel Cyclocondensation of Xanthates Containing Active Methylene Groups with Isothiocyanates. Spectral Data and X-Ray Structures of the Products.

Abstract A cyclocondensation reaction of S-(alkoxycarbonylmethyl)-and S-(cyanomethyl)dithiocarbonate O-esters with isothiocyanates in the presence of sodium tert-butoxide is described. Spectral data and X-ray structures of the main products are given.

C-N Coupling Reaction Catalyzed by Palladium on Carbon

The C-N coupling reaction of aryl alides and aryl amines with 10% palladium on carbon (2 mol% of Pd) in the presence of sodium tert-butoxide in mesitylene gave the corresponding triarylamines in 62-100% yield (15 examples). The catalyst recyclability was examined for the ­reaction of bromobenzene and morpholine under similar conditions in cyclopentylmethylether (CPME) to exhibit little loss of catalytic activity during three reusing runs (1st use: 82%, 2nd use: 89%, 3rd use: 90%, 4th use: 95%).

Ionic liquid-mediated Darzens condensation: An environmentally-friendly procedure for the room-temperature synthesis of α,β-epoxy ketones

This room-temperature Darzens condensation of α-chloroacetophenone with various aromatic aldehydes mediated by [bmim][BF4] ionic liquid in the presence of sodium tert-butoxide resulted in the sole formation of good to excellent yields of trans-α,β-epoxy ketones in short time periods. In contrast, tert-butyl 2-chloroacetate underwent Darzens reactions with aldehydes giving mixtures of both cis and trans products with low selectivity. In all reactions, the ionic liquid was recovered and reused in the subsequent reactions without significant loss of activity.

N-Heterocyclic Carbene Sulfonamide Palladium Complexes and Their Catalytic Activities in Suzuki−Miyaura Coupling Reaction

Novel N-heterocyclic carbene sulfonamide ligands derived from binaphthyl-2,2'-diamine (BINAM) and their tridentate NHC-Pd(II) complexes as well as their corresponding NHC-Pd(II) complexes bearing weakly coordinating acetate counterions have been successfully synthesized in good yields. These NHC-palladium(II) complexes have been characterized by X-ray crystal structure diffraction. Moreover, we found that these NHC-Pd(II) complexes bearing weakly coordinating acetate counterions are quite effective in Suzuki-Miyaura coupling reaction to give the corresponding products in good to excellent yields in most cases at room temperature in 2-propanol in the presence of sodium tert-butoxide.

Novel multi-spin-state linear hexanickel complexes [formula omitted] and their singly oxidized products [formula omitted] with 1,8-naphthyridine-based ligands: Tuning the redox properties of the metal string

The new ligand, 2,7-bis(α-pyrimidylamino)-1,8-naphthyridine (H 2bpmany), was prepared by the reaction of 2,7-dichloro-1,8-naphthyridine with 2-aminopyrimidine in the presence of sodium tert-butoxide under palladium-catalyzed conditions. The linear hexanickel Ni 6 11 + complexes [Ni 6(μ 6-bpmany) 4X 2]Cl (X = Cl ( 1); X = NCS ( 2)) and their singly oxidized products [Ni 6(μ 6-bpmany) 4X 2](BF 4) 2 (X = Cl ( 3); X = NCS ( 4)) have been synthesized, and compounds 1, 2 and 4 have been crystallographically characterized. The crystal structures of the Ni 6 11 + complexes show remarkably short Ni–Ni distances (ca. 2.22 Å), clearly indicative of partial metal–metal bonding in the mixed-valence Ni 2 3 + unit. This is also verified by the axial X-band EPR spectra of the complexes in solution. Magnetic susceptibility measurements reveal that the Ni 6 11 + complexes exhibit antiferromagnetic interactions ( J = −47 cm −1) between the terminal Ni 2+ ion and the central Ni 2 3 + unit, and the Ni 6 12 + complexes exhibit weak antiferromagnetic interactions ( J = −5 cm −1) between the two terminal Ni 2+ ions. The cyclic voltammograms display three reversible redox waves at E (1) 1/2 = +0.87, E (2) 1/2 = −0.02 and E (3) 1/2 = −0.46 V for 1, and E (1) 1/2 = +0.96, E (2) 1/2 = −0.01, and E (3) 1/2 = −0.41 V for 2. The relatively low potentials of E (2) 1/2 suggest that the Ni 6 11 + complexes can be easily converted to their Ni 6 12 + forms.

Palladium-catalysed arylation of sulfonamide stabilised enolates

α-Arylation of methanesulfonamides using palladium catalysis is described. For example, treatment of N-benzyl- N-methylmethanesulfonamide with catalytic Pd(OAc) 2 in the presence of sodium tert-butoxide, triphenylphosphine and toluene afforded N-benzyl- N-methylphenylmethanesulfonamide in 66% yield.

Unparalleled rates for the activation of aryl chlorides and bromides: coupling with amines and boronic acids in minutes at room temperature.

Unparalleled rates for the activation of aryl chlorides and bromides: coupling with amines and boronic acids in minutes at room temperature.

Synthesis of phosphorus- and selenium-containing macrocycles and their complexation with Pd(II)Cl2

A one-pot reaction was developed to synthesize phosphorus- and selenium-containing macrocycles starting from selenium via reduction with KBH4, treatment with bis[o-(bromomethyl)phenyl]phenylphosphine oxide 1 and reduction with KBH4 followed by the addition of an appropriate dibromide. Thus, ten- to seventeen-membered macrocycles 3 having one phosphorus and two selenium atoms were synthesized. In this synthesis an eight-membered heterocycle 4 was also obtained. In addition, the condensation of compound 1 with selenium-containing diols 7 and 8 in the presence of sodium tert-butoxide gave macrocyclic ligands 9 and 10, respectively. Reaction of these macrocycles with palladium(II) chloride gave 1 ∶ 1 complexes, except 9 which gave a 2 ∶ 1 complex. The molecular structures of the macrocycles 3c, 3f and 10 as well as the 2 ∶ 1 palladium(II) complex 21 of related 2-(p-methylphenoxy)-2-oxo-1,3,6,2-dioxaselenaphosphocane 20 have been established by X-ray diffraction.

Nickel-Catalyzed Amination of Aryl Chlorides

Aryl chlorides are converted to aniline derivatives using catalytic amounts of Ni(COD)2 (COD = 1,5-cyclooctadiene) and DPPF (DPPF = 1,1‘-bis(diphenylphosphino)ferrocene) or 1,10-phenanthroline in the presence of sodium tert-butoxide. This procedure has a broad substrate scope: electron-rich or electron-poor aryl chlorides, as well as chloropyridine derivatives, can be combined with primary and secondary amines to give the desired aryl amine products in moderate to excellent yields. Additionally, a procedure which utilizes the air-stable precatalysts (DPPF)NiCl2 or (1,10-phenanthroline)NiCl2 is also described.

Palladium-catalyzed synthesis of aryl-substituted polyamine compounds from aryl halides

The reaction of polyamines having primary amino groups and 1,2-diaminoethane and/or 1,3-diaminopropane fragments with aryl bromides or iodides in the presence of sodium tert-butoxide and (dppf)PdCl 2 (dppf = 1,1′-bis(diphenylphosphino)ferrocene) proceeds selectively leading to monoaryl-substituted derivatives of polyamine. This reaction provides a convenient method of arylation of di-, tri- and tetraamine compounds. The Pd-catalyzed reactions of 1,3-diaminopropane and 3,3′-diaminodipropylamine with more reactive 1-bromonaphthalene can be used for the preparation of sym-dinaphthyl derivatives of these amines.

Self-assembly by co-ordination and strong hydrogen bonding. X-ray crystal structures of a dimeric trisodium complex of a new acidic complexing ligand and its dihydrate

Abstract The new acidic complexing ligand triethanolamine-O,O,O-triacetic acid, 3, is synthesized by reaction of triethanolamine with chloroacetic acid in the presence of sodium tert-butoxide. The resulting Na complex, 4, and its dihydrate, 5, contain two ligand molecules, both with one Na+ ion interaction and both co-ordinated to a third, central, Na+ ion. In addition the acidic ligands are hydrogen bonded to each other, like carboxylic acids, and in 4, by three crystallographically symmetric hydrogen bonds, while in 5, due to the breakdown of symmetry, two normal and one crystallographically symmetrical hydrogen bond. Inside this extraordinary dimeric assembly (a pseudo-cryptate) are the three sodium ions encapsulated, like in cryptates, with a Na+…Na+ distance of 3.357(3) A (4) and 3.325(2) A (5). Crystal data, 4: a = 12.198(1) A, c = 40.926(5) A, V = 5274(3) A, trigonal, space group = R-3c (no. 157), d calc = 1.346 g cm−3, Z = 6, obs. refl. [I > σI] = 396, R = 0.045; 5: a = 25.045(5) A, b = 11.373(2) ...

Synthesis of α-OxoketeneO-Alkyl/Aryl,S-Alkyl Acetals

The synthesis of acylketene 0,5-dialkyl acetals 2 a-p and acylketene O-aryl S-alkyl acetals 6 a-i is described. The compounds 2a-n are obtained by base-catalyzed alkylation of the respective β-oxo thiono esters 4 a-n prepared by alkoxythiocarbonylation of active methylene ketones in the presence of sodium tert-butoxide. The corresponding O-dodecanyl 2o, O-benzyl 2p and O-aryl, S-methyl 6a-i acetals are synthesized via base-catalyzed displacement of the sulfonium salts 5a-b with the corresponding alkanol or phenol

A novel cyclocondensation of xanthates containing active methylene groups with isothiocyanates. Spectral data and X-ray structures of the products

A cyclocondensation reaction of S-(alkoxycarbonylmethyl)-and S-(cyanomethyl)dithiocarbonate O-esters with isothiocyanates in the presence of sodium tert-butoxide is described. Spectral data and X-ray structures of the main products are given.

Synthesis of 5-substituted 4-methylthio-1,3-thiazoline-2-thiones

We have established that the reaction proceeds primarily via pathway B with the formation, after methylation, of 4-methylthio-l,3-thiazoline-2-thiones. Thus methyl ester VII was obtained in the condensation of methyl methoxycarbonylmethylxanthogenate (I, R l = COOMe, R 2 = Me) with phenyl isothiocyanate (II) in DMF in the presence of sodium tert-butoxide with subsequent alkylation with methyl iodide.