Presence Of Et3N Research Articles

Practical method for PCB degradation using Pd/C–H2–Mg system

Polychlorinated biphenyls (PCBs) were mainly used as lubricants and coolants in electrical equipment. However, their chemical stabilities as well as hydrophobic properties caused persistent environmental pollution and damage to human health based on their bioaccumulative property. PCBs are currently targeted for worldwide elimination and should be disposed by 2028 based on the Stockholm Convention on Persistent Organic Pollutants. The conventional PCB degradation methods require high-heat, high-pressure or/and strongly basic conditions. The development of a safer and more practical method, therefore, is desired. We have reported a catalytic degradation method of PCBs based on a palladium on carbon (Pd/C)-catalyzed dechlorination in the presence of Et3N under ambient hydrogen pressure and temperature. In this study, we demonstrate a more practical system using magnesium metal instead of Et3N for the dechlorination of a variety of aromatic chlorides. The method was applicable for the complete degradation of a variety of PCB mixtures, such as Aroclor 1242, 1248, 1254 and PCBs removed from a capacitor to produce only biphenyl and magnesium chloride as the maritime component, both of which are less toxic and easily separable. Moreover, the Pd/C could be recovered and reused at least five times without any loss of catalytic activity. The present Pd/C–Mg–H2 system is a simple, safe, inexpensive, and environmentally-benign degradation method of PCBs.

Synthesis and Characterization of O,O'-Bis(α-Naphthyl, β-Naphthyl, and 2, 3, 5-Trimethylphenyl)Dithiophosphate Ligands

O,O′-Bis(α-Naphthyl, β-Naphthyl and 2,3,5-trimethylphenyl) dithiophosphate ligands have been isolated as triethylammonium salts, (α-C10H7O-, β-C10H7O, and (CH3)3C6H2O)2PS2HNEt3, by the reaction of α-C10H7OH, β-C10H7OH, or (CH3)3C6H2OH with P2S5 in presence of Et3N, in 4:1:2 molar ratio in chloroform under anhydrous conditions. Acidic form of these ligands, (α-C10H7O-, β-C10H7O-, or (CH3)3C6H2O)2PS2H, have been obtained by the direct reaction of α-C10H7OH, β-C10H7OH-, or (CH3)3C6H2OH with P2S5 in 4:1 molar ratio in presence of microwaves under solvent-free conditions. Both forms of the ligands have been converted into corresponding sodium salts, (α -C10H7O-, β-C10H7O-, or (CH3)3C6H2O)2PS2Na. These compounds have been characterized by elemental analyses (C, H, N, and S) and mass, IR, and NMR (1H, 13C and 31P) spectroscopic studies. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.

Synthesis and Structures of Dinuclear Copper(I) and Silver(I) 1, 3‐Bis[(2‐chloro)benzene]triazenide Complexes

AbstractIn the presence of Et3N, the reaction of 1, 3‐bis[(2‐chloro)benzene]triazene (HL) with CuCl or AgNO3 gives the triazenide complexes {Cu2(L)2} (1) and {Ag2(L)2} (2), respectively. The X‐ray crystal structures of both complexes were obtained. The metal–metal distances (Cu···Cu and Ag···Ag) are 2.4974(5) and 2.7208(5) Å, respectively.

Synthetic and Structural Investigations on Some New 1,2,4,5-(CH2)4C6H2 Moiety-Containing Butterfly Fe/S Cluster Complexes from Reactions of Tetrathiol 1,2,4,5-(HSCH2)4C6H2 with Fe3(CO)12 or with Fe3(CO)12 in the Presence of Et3N

The 1,2,4,5-(CH2)4C6H2 moiety-containing butterfly Fe/S complexes [1,2-(CH2S2CH2)-4,5-(μ-SCH2)2C6H2][Fe2(CO)6] (1), [1,2,4,5-(μ-SCH2)4C6H2][Fe2(CO)6]2 (2), and [(1,2-Me2)-4,5-(μ-SCH2)2C6H2][Fe2(CO)6] (3) have been prepared by the reaction of tetrathiol 1,2,4,5-(HSCH2)4C6H2 with Fe3(CO)12 under different conditions. Treatment of complex 1 with PPh3 or PMe3 in the presence of Me3NO or with the in situ generated N-heterocyclic carbene IMes (IMes = 1,3-bis(mesityl)imidazol-2-ylidene) afforded the corresponding monosubstituted single-butterfly complexes [1,2-(CH2S2CH2)-4,5-(μ-SCH2)2C6H2][Fe2(CO)5L] (4, L = PPh3; 5, L = PMe3; 6, L = IMes). However, in contrast to the above-mentioned reaction of tetrathiol 1,2,4,5-(HSCH2)4C6H2 with Fe3(CO)12, the reactions of 1,2,4,5-(HSCH2)4C6H2 with Fe3(CO)12 in the presence of Et3N, followed by treatment with PhCOCl or PhC(Cl)═NPh, resulted in formation of the quadruple- and triple-butterfly complexes [(μ-PhC═O)Fe2(CO)6]4[1,2,4,5-(μ-SCH2)4C6H2] (7) and [(μ-PhC═NPh)Fe2(CO)6]2[...

Nanocomposite materials based on isosorbide methacrylate/Cloisite 20A

AbstractThis paper reports experiments on grafting of a new polymerizable monomer onto organophilic montmorillonite. The monomer, 5‐methacryloyloxy‐1,4:36‐D‐anhydrosorbitol (MAS), was synthesized by reacting methacryloyl chloride and isosorbide in the presence of Et3N as base. Then, Cloisite 20A was reacted with vinyltrichlorosilane to replace the edge hydroxyl groups of the clay with a vinyl moiety. Because the reaction liberates HCl, it was performed in the presence of sodium hydrogen carbonate to prevent the exchange of quaternary alkylammonium cations with H+ ions. Only the silanol groups on the edge of the clay react with vinyltrichlorosilane. After the reaction, the product maintained the same basal spacing as the precursor. The radical polymerization of the product with MAS as a vinyl monomer led to chemical grafting of the polymer onto the montmorillonite surface. The homopolymer formed during polymerization was separated from the grafted organoclay by Soxhlet extraction. Chemical grafting of the polymer onto Cloisite 20A was confirmed using infrared spectroscopy. The prepared nanocomposite materials and the grafted nanoparticles were studied using X‐ray diffraction and scanning and transmission electron microscopy. Exfoliated nanocomposite was obtained for 1 wt% clay loadings. The nanocomposites were studied using thermogravimetric and dynamic mechanical analyses. Improved thermal properties were observed for nanocomposites with 1–5 wt% clay content. © 2012 Society of Chemical Industry

Synthesis and Reactivity of 1-[(2-methoxy)benzene]- 3-[benzothiazole]Triazene With Copper(II) or Cobalt(II) Chloride

A new triazene, 1-[(2-methoxy)benzene]-3-[benzothiazole] triazene (HL), has been synthesized and charaterized. In the presence of Et3N, the reaction of HL and CuCl2·2H2O or CoCl2·6H2O gives the triazenide complexes [Cu4L′4(μ-OMe)4] 1 (L′ 1-[benzothiazole]triazene ion) and [Co2L4] 2, respectively. The X-ray crystal structures of both complexes have been obtained. Magnetic studies indicate significant antiferromagnetic coupling between the copper(II) centers or cobalt(II) centers for complexes 1 and 2, with coupling constants (J) of –587 cm−1 for 1 and –147 cm−1 for 2. Complex 2 shows one reversible one-electron redox wave at –0.835 V, and one irreversible oxidation at –0.193 V, which are in accord with the redox potentials of [CoIII-CoII]/[CoII-CoII] and [CoIII-CoIII]/[CoII-CoII] couples, respectively.

Solvent effect on copper-catalyzed azide–alkyne cycloaddition (CuAAC): Synthesis of novel triazolyl substituted quinolines as potential anticancer agents

A regioselective route to novel mono triazolyl substituted quinolines has been developed via copper-catalyzed azide–alkyne cycloaddition (CuAAC) of 2,4-diazidoquinoline with terminal alkynes in DMF. The reaction provided bis triazolyl substituted quinolines when performed in water in the presence of Et3N. A number of the compounds synthesized showed promising anti-proliferative properties when tested in vitro especially against breast cancer cells.

Synthesis of Some New 2‐Oxo‐N‐[(10H‐phenothiazin‐10‐yl)alkyl] Derivatives of Azetidine‐1‐carboxamides

AbstractThe synthesis of a new series of 4‐aryl‐3‐chloro‐2‐oxo‐N‐[3‐(10H‐phenothiazin‐10‐yl)propyl]azetidine‐1‐carboxamides, 4a–4m, is described. Phenothiazine on reaction with Cl(CH2)3Br at room temperature gave 10‐(3‐chloropropyl)‐10H‐phenothiazine (1), and the latter reacted with urea to yield 1‐[3‐(10H‐phenothiazin‐10‐yl)propyl]urea (2). Further reaction of 2 with several substituted aromatic aldehydes led to N‐(arylmethylidene)‐N′‐[3‐(phenothiazin‐10‐yl)propyl]ureas 3a–3m, which, on treatment with ClCH2COCl in the presence of Et3N, furnished the desired racemic trans‐2‐oxoazetidin‐1‐carboxamide derivatives 4a–4m. The structures of all new compounds were confirmed by IR, and 1H‐ and 13C‐NMR spectroscopy, FAB mass spectrometry, and chemical methods.

Unexpected Formation of a Cobalt(III) Phenoxazinylate Electron Reservoir

AbstractThe redox‐active ligand N,N′‐bis(3,5‐di‐tert‐butyl‐2‐hydroxyphenyl)‐1,2‐phenylenediamine (H4L), known for supporting catalytic processes with both late and early transition metals, unexpectedly undergoes an unusual and thus far unobserved cyclization. Upon equimolar treatment of a cobalt(II) salt in the presence of Et3N under aerobic conditions, a ligand rearrangement occurs to afford an unprecedented phenoxazinyl radical moiety (L′). The resulting bisligated Co complex, thoroughly characterized structurally and electronically and analyzed by multiple experimental and computational approaches, is presented. It is shown to traverse oxidation states from 2+ to 3–, spanning a thermodynamic window of approximately 2 V.

Synthesis of Nano Machines Based on Catenanes and Rotaxanes

A nanomachine is an assembly of a discrete number of supramolecular components designed to perform mechanical like movements as a consequence of appropriate external stimuli. In this research work we wish report synthesis of a part of nanomachines are based on interlocked macrocycle named rotaxanes, catenanes, pseudorataxane and knots, that Bis aza thiacrown compound (5) was synthesized by macrocyclic diamide (4) and 2, 6-dicarbonyldicholoride pyridine in dry CH2Cl2 and was refluxed in presence of Et3N in good yield. The structures of these compounds were confirmed by IR, 1H NMR, 13C NMR and elemental analysis.

An efficient one-pot multicomponent approach to 5-amino-7-aryl-8-nitrothiazolo[3,2- a]pyridines

A series of thiazolo[3,2- a]pyridines have been prepared using a multicomponent reaction between aromatic aldehydes, 2-nitromethylenethiazolidine and nitriles containing an active methylene group (malononitrile, ethyl 2-cyanoacetate and 2-phenylsulfonylacetonitrile) in the presence of Et 3N under mild conditions with high yields. One of the compounds shows promising anticancer activity across a range of cancer cell lines.

Synthesis, Structure, and Olefin Polymerization Behavior of Nickel Complexes with Carborane [S,C] or [S,S] Ligands

The o-carborane [S,C] ligand 1 (1-(2′-(S)PPh2)-o-carborane) was prepared by the reaction of a monophosphino o-carborane with elemental sulfur in the presence of Et3N. Ligand 1 was lithiated with n-...

Efficient Carbonylation of Aryl and Heteroaryl Bromides under Atmospheric Pressure of CO

In the presence of Et3N and n-BuOH, efficient alkoxycarbonylation of (hetero)aromatic bromides was achieved under atmospheric pressure of carbon monoxide with in situ generated palladium/rac-BINAP as catalyst.

Aminophosphine–palladium(II) complexes: Synthsesis, structure and applications in Suzuki and Heck cross-coupling reactions

Reaction of furfurylamine with 1 or 2 equivalents of PPh 2Cl in the presence of Et 3N, proceeds under anaerobic conditions in thf to give furfuryl-2-( N-diphenylphosphino)amine, Ph 2PNHCH 2-C 4H 3O, 1 and furfuryl-2-( N, N-bis(diphenylphosphino)amine), (Ph 2P) 2NCH 2-C 4H 3O, 2, respectively. The reactions of 1 and 2 with MCl 2(cod) (M = Pd, Pt; cod = 1,5-cyclooctadiene) or Pt(CH 3) 2(cod) yield complexes [M(Ph 2PNHCH 2-C 4H 3O) 2Cl 2] (M = Pd 1a, Pt 1b), [Pt(Ph 2PNHCH 2-C 4H 3O) 2(CH 3) 2] ( 1c), and [M((Ph 2P) 2NCH 2-C 4H 3O)Cl 2] (M = Pd 2a, Pt 2b), [Pt((Ph 2P) 2NCH 2-C 4H 3O)(CH 3) 2] ( 2c), respectively. All the compounds were isolated as analytically pure substances and characterized by NMR, IR spectroscopy and elemental analysis. Representative solid-state structures of 2a and 2b were also determined by X-ray single crystal diffraction technique. Furthermore, the palladium complexes 1a and 2a were tested and found to be highly active catalysts in the Suzuki coupling and Heck reaction affording biphenyls and trans-stilbenes, respectively.

Synthesis, structures, and magnetic behavior of two high-spin binuclear Fe(III) complexes

The reaction of 2-t-butyl-4-ethylphenol, formaldehyde, and 2-amino propanol or 3-amino-1-propanol at 2 : 2 : 1 provides N-(1-ethanol)-N,N-bis(3-t-butyl-5-ethyl-2-hydroxybenxyl)amine (H3L′) and N-(3-amino-1-propanol)-N,N-bis(3-t-butyl-5-ethyl-2-hydroxybenxyl)amine (H3L″), respectively. In the presence of Et3N, the reaction of FeCl3 · 6H2O and H3L′ or H3L″ gives dinuclear Fe(III) complexes [] 1 and [] 2, respectively, which have been characterized by X-ray crystallography, magnetic measurements, and cyclic voltammetry (CV). Magnetic studies indicate significant antiferromagnetic coupling between the iron(III) centers for 1 and 2. The values obtained for the coupling constants (J) are −12.35 cm−1 for 1 and −16.26 cm−1 for 2. CVs of 1 and 2 reveal one reversible wave at −0.80 and −0.82 V versus AgCl/Ag, respectively, which can be ascribed to redox coupling of FeIIIFeII/FeIIIFeIII.

Synthesis and Characterization of Single, Double, and Triple Butterfly [2Fe2E] (E = Se, S) Cluster Complexes Related to the Active Site of [FeFe]-Hydrogenases

As the active site mimics of [FeFe]-hydrogenases, 14 new butterfly [2Fe2E] (E = Se, S) cluster complexes have been prepared by various synthetic routes. The N-substituted single-butterfly [2Fe2Se] complexes [(μ-SeCH2)2NC(O)R]Fe2(CO)6 (1, R = Me; 2, R = Ph; 3, R = PhCH2O) were prepared by reactions of the in situ formed (μ-LiSe)2Fe2(CO)6 with RC(O)N(CH2Cl)2, whereas the corresponding [2Fe2S] complexes [(μ-SCH2)2NC6H4R-p]Fe2(CO)6 (4, R = CO2Et; 5, R = CH2OH) were produced by reaction of the in situ generated (μ-HS)2Fe2(CO)6 with aqueous CH2O followed by treatment with p-RC6H4NH2. The parent single-butterfly [2Fe2Se] complex [(μ-SeCH2)2NH]Fe2(CO)6 (6) could be prepared by reaction of the N-substituted complex 3 with deprotecting reagent BBr3, BF3·OEt2/EtSH, or BF3·OEt2/Me2S, whereas the N-substituted single-butterfly [2Fe2Se] complexes [(μ-SeCH2)2NC(O)R]Fe2(CO)6 (7, R = Et; 8, R = PhCH2) were produced by reactions of 6 with acylating agents RC(O)Cl in the presence of Et3N. While the known parent single-butterfly [2Fe2S] complex [(μ-SCH2)2NH]Fe2(CO)6 reacted with 2,6-[ClC(O)]2C5H3N to afford double-butterfly [2Fe2S] complex [Fe2(CO)6(μ-SCH2)2NC(O)]2(2,6-C5H3N) (9), the new N-hydroxyethyl-substituted single-butterfly [2Fe2Se] complex [(μ-SeCH2)2N(CH2)2OH]Fe2(CO)6 (10) could be obtained by the in situ reaction of (μ-HSe)2Fe2(CO)6 with (HOCH2)2N(CH2)2OH. Interestingly, complex 10 could react with [ClC(O)]2CH2 or 1,3,5-[ClC(O)]3C6H3 in the presence of Et3N to give the corresponding double-butterfly [2Fe2Se] complex [Fe2(CO)6(μ-SeCH2)2N(CH2)2O2C]2CH2 (11) and triple-butterfly complex [Fe2(CO)6(μ-SeCH2)2N(CH2)2O2C]3(1,3,5-C6H3) (12), whereas the known single-butterfly [2Fe2S] complex [(μ-SCH2)2N(CH2)2OH]Fe2(CO)6 could react with 2,6-[ClC(O)]2C5H3N and 1,3,5-[ClC(O)]3C6H3 in the presence of Et3N to afford the corresponding double-butterfly [2Fe2S] complex [Fe2(CO)6(μ-SCH2)2N(CH2)2O2C]2(2,6-C5H3N) (13) and triple-butterfly complex [Fe2(CO)6(μ-SCH2)2N(CH2)2O2C]3(1,3,5-C6H3) (14), respectively. All the new complexes 1–14 have been characterized by elemental analysis and spectroscopy, as well as by X-ray crystallography for 1–4, 7–9, and 14. In addition, the electrochemical study indicated that complexes 1 and 2 can catalyze the proton reduction of HOAc to give hydrogen.

ChemInform Abstract: Triethylamine‐Catalyzed Efficient Synthesis of Oxathiolanes Containing a Highly Polarized Carbon—Carbon Double Bond from Reaction of Malononitrile, Carbon Disulfide (CS2), and Oxiranes.

An efficient synthesis of functionalized 2-(1,3-oxathiolan-2-ylidene)malononitriles containing a push-pull CC bond via a simple reaction between malononitrile, CS2, and oxiranes in the presence of Et3N is described (Scheme 1).

ChemInform Abstract: The Witkop—Winterfeldt Oxidation Converts Tetrahydropyridoindoles into Pyrroloquinolones and Cinnolines by an Unprecedented Scaffold Rearrangement.

AbstractTosylated γ‐carbolines (I) are converted into dihydroquinolones (II) by a one‐pot reaction via ozone oxidation, reduction of the assumed intermediate ozonide by pyridine, and final cyclization of the formed keto‐lactam in the presence of Et3N.

Total synthesis of crispine A enantiomers through a Burkholderia cepacia lipase-catalysed kinetic resolution

Both enantiomers of the antitumour-active alkaloid crispine A (ee = 95%) were synthesised through the Burkholderia cepacia lipase-catalysed acylation of the primary hydroxy group of N-Boc-protected 1-(3-hydroxypropyl)-6,7-bis(methyloxy)-1,2,3,4-tetrahydroisoquinoline (±)- 3 and the enantioselective hydrolysis of the corresponding O-decanoate (±)- 4 [R = (CH 2) 8Me] with a remote, four-atom distant stereogenic centre. High enantioselectivities were observed for the ( S)-selective O-acylation with vinyl decanoate in the presence of Et 3N and Na 2SO 4 in t-BuOMe at 45 °C ( E = 68), and for the ( S)-selective hydrolysis with H 2O in t-BuOMe at 45 °C ( E = 52). The enzymatic resolutions, performed in two steps, afforded the key alcohol and ester enantiomers with high enantiomeric excesses (ee ⩾ 94%). Ring-closure reactions of alcohol enantiomers (+)- 3 and (−)- 3 with thionyl chloride afforded the desired crispine A enantiomers (+)- 1 and (−)- 1 (ee ⩾ 95%).

ChemInform Abstract: Synthesis and Crystal Structure of Novel [1,2,4]Oxadiazolo[5,4‐d][1,5]benzothiozepine Derivatives Containing Pyrazole Moiety.

A series of new substituted-[1,2,4]oxadiazolo[5,4-d][1,5]benzothiazepine derivatives containing pyrazole ring 4/4′ was synthesized by substituted-pyrazolo[1,5]benzothiazepines 2/2′ and substituted-benzohydroximinoyl chlorides 3 through the 1,3-dipolar cycloaddition reaction in the presence of Et3N at room temperature, and characterized by MS, IR, 1H NMR and elemental analyses. In addition, the structure of 4′l was determined by X-ray crystallography. J. Heterocyclic Chem., 2011.