Base In Acetonitrile Research Articles

Synthesis, spectroscopic, electrochemistry and antioxidant properties of benzofuroxan and 2H-benzimidazole 1,3-dioxide derivatives: Effects of conjugation with electron-acceptor 1,2,3-triazolyl-1,2,4-oxadiazole

A series of novel benzofuroxan and of 2,2-dimethyl-2H-benzimidazole 1,3-dioxide derivatives conjugated to the strong electron-withdrawing 1,2,4-oxadiazole ring and to the amide isostere 1,2,3-triazole were synthesized. NHeterocycle-N-oxide-bearing carboxylic acids and 1,2,3-triazole-4-carbamidoximes served as convenient reactants for the obtention of the 1,2,4-oxadiazoles. By employing O-(benzotriazol-1-yl)-N,N,N’,N’-tetramethyluronium tetrafluoroborate (TBTU) as coupling reagent and 1,8-diazabicyclo[5.4.0]undec‑7-ene (DBU) as base in acetonitrile, in a one-pot sequence, at room temperature, products were obtained in generally high yields (64 – 93 %) after two 30 min steps and a simple purification process. NMR spectroscopy, X-Ray diffraction and DFT calculations helped to access the preferential tautomeric structures of selected compounds. UV–Vis spectroscopy revealed characteristic absorption peaks for 1,2,3-triazolyl-1,2,4-oxadiazoles 11aa-be, noteworthy an intramolecular charge transfer (ICT) band around 500–650 nm for benzimidazole-1,3-dioxide derivatives 11ba-be, while low fluorescence quantum yields and Stokes shifts were observed for all compounds. Both oxidation and reduction peaks were observed in Cyclic Voltammetry experiments, including irreversible reduction peaks for all 11aa-be compounds. TD-DFT calculations enabled comprehension of the molecular orbitals participation in the UV–Vis transitions, which depend on the N-oxide, the heterocycles and the substituted phenyl ring. Also, some compounds with electron withdrawing groups (Cl and CF3) also displayed good antioxidant activity in DPPH assays.

A new approach to the determination of pKa and pKb of Brønsted–Lowry weak acid and weak base in aprotic solvent

• Developing a method of determining the dissociation constants of weak acid and base in acetonitrile. • Unambiguous voltammetric peak potentials were used to exactly measure pK a and pK b . • Compared with using potentiometry, the method is simple and rapid because of using cyclic voltammetry. The pK a and pK b of Bronsted–Lowry weak acids and weak bases in aprotic solvents are difficult to accurately determine. Herein, we found that in an aprotic solvent, the conjugate base of weak acid can produce a new, unambiguous anodic peak of hydroquinone, and the conjugate acid of weak base can produce a new cathodic peak of p-benzoquinone. These new peaks were due to the drastic change in pH near the electrode surface, and their potentials depended on the strength of conjugate acids and bases but not on the concentration of hydroquinone and quinone. Therefore, the conjugate acid–base dissociation constant can be measured by the new peak potential. Then, the weak acid–base dissociation constant can be obtained by the difference between the autoprotolysis constant of the aprotic solvent and the conjugate acid–base dissociation constant. The experimental results were consistent with those in literature.

Influence of Steric Effect on the Pseudo-Multicomponent Synthesis of N-Aroylmethyl-4-Arylimidazoles.

A pseudo-three-component synthesis of N-aroylmethylimidazoles 3 with three new C–N bonds formed regioselectively under microwave conditions was developed. Products were obtained by reacting two equivalents of aroylmethyl bromide (ArCOCH2Br, 1) with the appropriate amidine salt (RCN2H3.HX, 2) and with K2CO3 as a base in acetonitrile. The bicomponent reaction also occurred, giving the expected 4(5)-aryl-1H-imidazoles 4. Notably, the ratio of products 3 and 4 is governed by steric factors of the amidine 2 (i.e., R = H, CH3, Ph). Therefore, a computational study was carried out to understand the reaction course regarding product ratio (3/4), regioselectivity, and the steric effects of the amidine substituent group.

Unsupported Nanoporous Palladium Catalyst for Highly Selective Hydrogenation of Carbon Dioxide and Sodium Bicarbonate into Formate

AbstractDeveloping an efficient and simple heterogeneous catalytic system for CO2 conversion into formic acid (FA) is a vibrant research area because FA is recognized as a liquid organic hydrogen carrier. On the basis of our previous work on unsupported nanoporous palladium‐catalyzed hydrogenation proceeding through a Pd‐hydride intermediate, we report herein four types of PdNPore catalysts for the CO2 hydrogenation. The PdNPore‐1 catalyst exhibited high catalytic activity for CO2 hydrogenation into formate and obtained a yield of 86 % at 80 °C under H2 (1.0 MPa) and CO2 (1.5 MPa) with 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) as a base in acetonitrile. Moreover, the catalyst was easily recovered and reused without any loss of catalytic activity. Sodium bicarbonate could also be hydrogenated using the PdNPore‐1 catalyst.

A Study on the Rearrangement of Dialkyl 1-Aryl-1-hydroxymethylphosphonates to Benzyl Phosphates

The phospha-Brook rearrangement of dialkyl 1-aryl-1-hydroxymethylphosphonates (HPs) to the corresponding benzyl phosphates (BPs) has been elaborated under solid-liquid phase transfer catalytic conditions. The best procedure involved the use of triethylbenzylammonium chloride as the catalyst and Cs2CO3 as the base in acetonitrile as the solvent at room temperature. The substrate dependence of the rearrangement has been studied, and the mechanism of the transformation under discussion was explored by quantum chemical calculations. The key intermediate is an oxaphosphirane. The one-pot version starting with the Pudovik reaction has also been developed. The conditions of this tandem transformation were the same, as those for the one-step HP→BP conversion.

One-step electrochemical deposition of thin film titanium suboxide in basic titanyl sulfate solution at room temperature

This study reports direct electrodeposition of TiOx thin films on ITO substrate from an acetonitrile solution containing titanyl sulfate and tetra n-butyl ammonium hydroxide. The electrochemical behavior of titanyl sulfate in a basic medium is investigated using cyclic voltammetry. In this medium, different phases and/or compositions containing Ti3O5 (βTi3O5, λTi3O5, and ɣTi3O5) and Ti4O7 are obtained depending on electrolysis potential values (− 1.2 V, − 1.5 V, − 1.7 V, and − 2.0 V). The electrochemical properties of the TiOx coatings obtained from various cathodic potentials are investigated using electrochemical impedance spectroscopy (EIS). Depending on the increase of electrolysis potential values applied, thicker films with lower resistance are formed. The EIS analysis results are compatible with the results of XRD and SEM, which confirms the change of phase content and/or composition in the films obtained at different electrolysis potential values. The estimated band gaps of brownish thin films are obtained between 1.32 and 1.41 eV using UV–vis spectra. Herein the electrochemical deposition of crystalline TiOx films on ITO electrode is carried out at room temperature by a cost-effective and one-step method in basic acetonitrile solution.

The Role of H-Bonding in Nonconcerted Proton-Coupled Electron Transfer: Explaining the Voltammetry of Phenylenediamines in the Presence of Weak Bases in Acetonitrile

The kinetics of many proton-coupled electron transfer (PCET) reactions cannot be adequately described by stepwise proton and electron transfer. Concerted electron–proton transfer (CPET) is another ...

Selectivity control of CO versus HCOO− production in the visible-light-driven catalytic reduction of CO2 with two cooperative metal sites

It is highly desirable to discover molecular catalysts with controlled selectivity for visible-light-driven CO2 reduction to fuels. In the design of catalysts employing earth-abundant metals, progress has been made for CO production, but formate generation has been observed more rarely. Here, we report a binuclear Co complex bearing a bi-quaterpyridine ligand that can selectively reduce CO2 to HCOO− or CO under visible light irradiation. Selective formate production (maximum of 97%) was obtained with a turnover number of up to 821 in basic acetonitrile solution. Conversely, in the presence of a weak acid, CO2 reduction affords CO with high selectivity (maximum of 99%) and a maximum turnover number of 829. The catalytic process is controlled by the two Co atoms acting synergistically, and the selectivity can be steered towards the desired product by simply changing the acid co-substrate. Performing photocatalytic CO2 reduction in a selective fashion with molecular catalysts represents a considerable challenge. Here, a binuclear cobalt complex featuring a bi-quaterpyridine ligand is developed that can selectively afford either carbon monoxide or formate by selection of the reaction medium acidity.

The Role of H-Bonding in Proton-Coupled Electron Transfer: The Reduction of N-Methyl-4,4’-Bipyridine Radical in Acetonitrile in the Presence of Acidic Alcohols

Proton-coupled electron transfer reactions (PCET) play a significant role in many chemical and biological mechanisms. However, although these reactions have been known and studied for over a century, it is only within the last few decades that the importance of H-bonding intermediates in these reactions has come to be appreciated. In previous studies, we examined how explicit consideration of electron transfer and proton transfer within a H-bond intermediate (the “wedge” scheme) could explain the voltammetry of oxidation reactions involving phenylenediamines and bases in acetonitrile. The focus of this new study is to see if the wedge scheme can also explain the chemically reversible PCET reaction due to addition of acidic alcohols to the N-methyl-4,4’-bipyridinium redox couple (commonly called “monoquat” or MQ) in acetonitrile. MQ, which starts out as a +1 cation, undergoes two reversible reductions in acetonitrile, first to an uncharged radical and then to a quinoidal anion. For this study, different types of acidic alcohols, such as trifluoromethanol, methanol, and dichloroethanol, were added at different concentrations. The cyclic voltammetry shows a positive shift in the E1/2 of the second reduction after adding the acidic alcohol as a guest. This is likely due to protonation of the monoquat anion by the alcohol. The overall reaction was expected to be MQ + ROH + e- = MQH + RO-, which would show a 60 mV per log[ROH] change in E1/2. However, analysis of the collected data contradicts this hypothesis by giving a 180 mV per log[ROH] E1/2 shift, indicating that three alcohols are involved in the overall reaction. Since it is highly unlikely that the MQ anion would be triply protonated, our current hypothesis is that the product conjugate base of the alcohol forms a strongly H-bonded complex with two other alcohols, making the overall reaction, MQ + 3ROH + e- = MQH + (RO-)(ROH)2. Results of on-going research to either disprove or provide further support for this hypothesis will be reported.

The Role of H-Bonding in Non-Concerted Proton-Coupled Electron Transfer: Explaining the Voltammetry of Phenylenediamines in the Presence of Weak Bases in Acetonitrile

The kinetics of many proton-coupled electron transfer (PCET) reactions cannot be adequately described by step-wise proton and electron transfer. Concerted electron-proton transfer (CPET) is another possibility, but examples exist where step-wise mechanisms are not viable yet there is no compelling evidence for CPET. This study investigates such a reaction, the oxidation of an NH-containing phenylenediamine radical cation, H2PD+, in the presence of pyridines in acetonitrile. H2PD+ is formed by a net one electron oxidation of 2,3,5,6-tetramethylphenylenediamine in acetonitrile via a rather complicated mechanism that likely proceeds through a H-bonded dimer. Once formed, it can be further oxidized at more positive potentials to the quinoidal dication, H2PD2+, which will be considerably more acidic than the radical cation. Indeed, the E1/2 for the radical oxidation jumps to a considerably more negative potential upon addition of 1 equivalent of the weak base pyridine. The CV wave broadens but stays chemically reversible. Further addition of pyridine leads to smaller E1/2 shifts with continued reversibility. This behavior could possibly be explained by stabilization of H2PD2+ through H-bonding or proton transfer to pyridine, however, UV-vis spectroelectrochemical experiments provide definitive evidence for proton transfer. Furthermore, CV studies with 4-substituted pyridine derivatives of weaker basicity show that the observed E1/2 with 1 equivalent of the pyridine depends in a Nernstian fashion on the pKa of the conjugate acid of the pyridine, indicating that all the pyridines studied deprotonate H2PD2+ to give the quinoidal cation, HPD+. The continued E1/2 shift observed upon further addition of the pyridines can then be completely explained by application of the Nernst equation to the overall reaction H2PD+ + pyr → HPD+ + Hpyr+ + e−. However, while this explains the thermodynamics, the classic step-wise proton-electron transfer mechanism for this reaction cannot explain the observed reversibility at high base concentration. In contrast, the reversibility can be explained by a “wedge” scheme mechanism in which electron and proton transfer occur within the H-bond complex formed as an intermediate in proton transfer. In this case, the electron-proton transfer could be concerted, however, the kinetics for the second oxidation in the presence of pyridine show no significant isotope effect. Furthermore, a new reduction peak that appears at faster scan rates suggests the presence of an intermediate in the electron-proton transfer. Both results strongly suggest that the electron-proton transfer is step-wise, not concerted, within the H-bond complex. This result points to the important role H-bonding may play in PCET even without CPET.

From Pincer to Paddlewheel: C-H and C-S Bond Activation at Bis(2-pyridylthio)methane by Palladium(II).

The bis(2-pyridylthio)methanidopalladium(II) pincer complex (1), containing a Pd-C bond, was obtained from the reaction of bis(2-pyridylthio)methane (H2L) with palladium(II) acetate in toluene under reflux. When palladium(II) trifluoroacetate was used, H2L reacted to generate the tetrakis(pyridine-2-thiol)palladium(II) complex (2). Complex 2 was converted to a heterobimetallic palladium(II)-iron(II) paddlewheel complex (3) upon treatment with iron(II) triflate in the presence of a base in acetonitrile at room temperature.

TsNBr2 promoted decarboxylative bromination of α,β-unsaturated carboxylic acids

A rapid process for decarboxylative bromination of α,β-unsaturated carboxylic acids have been developed using N,N-dibromo-p-toluenesulfonamide (TsNBr2). Treatment of cinnamic acids with TsNBr2 in presence of potassium carbonate in acetonitrile produces corresponding β-bromostyrenes at room temperature. Exclusive formation of (E)-β-bromostyrenes was observed in a stereoselective manner within a very short period of time (5–15 min). This method was further extended for obtaining 1-bromoalkynes from corresponding propiolic acids. Instantaneous formation of bromoalkynes was observed when the reaction was carried out in presence of DBU as a base in acetonitrile at room temperature. A wide variety of cinnamic acids and propiolic acids could be converted to corresponding β-bromostyrenes and 1-bromoalkynes respectively under mild reaction condition with high to excellent yield.

Multicomponent Solvent-Free Synthesis, Antibacterial Evaluation and QSAR Study of 2-(Bis(benzylthio)methylene) malononitriles

Multicomponent reaction of malononitrile, carbon disulphide and various benzyl halides was developed as an efficient strategy for the synthesis of 2-(bis(benzylthio)methylene)malononitrile derivatives via two different procedures: (a) in the presence of K2CO3 as a base in acetonitrile and (b) under solvent-free conditions in the presence of triethylamine. Higher yields with shorter reaction times were obtained from the latter procedure. Inhibitory activity of all derivatives was evaluated against 22 pathogenic bacteria including both Gram-negative and Gram-positive strains. Thioether 4b showed broad-spectrum antibacterial activities according to the antibiogram tests. DFT calculations (B3LYP/6-311++G**) were performed to determine the type of drug-receptor interactions. It was found that reversible dipole-dipole forces play a key role in most interactions.

A highly selective fluorescent probe for Cu2+ based on a diarylethene with a benzo[1,2,5]oxadiazol-4-ylamine Schiff base unit

A new photochromic diarylethene derivative with a benzo[1,2,5]oxadiazol-4-ylamine Schiff base unit was synthesized and its photochromic and fluorescent properties were systematically investigated in detail by the stimulation of light, metal ions, acid, and base in acetonitrile. Especially, upon addition of Cu2+, its emission peak was blue-shifted by 56 nm and the emission intensity was obviously enhanced by 90 fold, accompanied by the fluorescent color changed from dark red to bright red. And when HCl (0.1 mol L−1) was added into, on the vision, the change of the solution color could be easily seen from yellow to purple. As a result, the diarylethene derivative can sever as a highly selective fluorescent sensor for recognition of Cu2+. Furthermore, the photochromic and fluorescence behavior of the diarylethene derivative to Cu2+ and acid could be applied to the design of molecular logic circuit. More importantly, the diarylethene derivative also can be applied to detect Cu2+ in natural water samples with high accuracy.

Evaluating the Roles of Proton Transfer and H-Bonding in the Electron Transfer Reactions of Organic Redox Couples in Non-Aqueous Solvents: Oxidation of Phenylenediamines in the Presence of Pyridine Bases in Acetonitrile

Oxidation or reduction of organic redox couples typically leads to large changes in acidity or basicity, withthe result that proton transfer often accompanies electron transfer, particularly in aqueous solution. In lesspolar organic solvents, H-bonding also can play an important role. While it is generally appreciated thatproton transfer will have a greater effect on the overall reaction than H-bonding, it is not always straightforward to distinguish between the two, and, despite a considerable amount of research, a complete,quantitative understanding of the relative roles that the two play in the voltammetry that is observed uponaddition of acids or bases to organic redox couples in non-aqueous solution remains elusive. This study focuses on the electrochemistry of p-tetramethylphenylenediamine, H 2 PD, in acetonitrile in thepresence of pyridine bases. In acetonitrile, this compound undergoes a reversible one electron oxidationto the radical cation, H 2 PD + , followed by a second reversible oxidation to the strongly acidic quinoidaldication, H 2 PD 2+ . With the addition of 1 equivalent of the pyridine base, no significant change in the firstoxidation is observed, but there is a large negative shift in the E 1/2 of the second oxidation with no loss inreversibility. Subsequent additions show a smaller, incremental negative shift, still with no loss inreversibility. We believe that this behavior signals proton transfer is occurring between the pyridine, pyr,and the H 2 PD 2+ , so that the overall reaction occurring in the second oxidation corresponds to H 2 PD + + pyr= HPD + + Hpyr + + e-. In this case, the observed E 1/2 should depend linearly on the pK a of the Hpyr + with aslope of −60 mV/pH unit. To test this hypothesis, the voltammetry of H 2 PD was studied with differentpyridines that cover a range of pK a values. A plot of E 1/2 of the wave observed with 1 eq pyridine vs. pKa isindeed linear with close to the predicted slope. Furthermore, it is found that the continued shift in E 1/2 ofthe second oxidation with increasing concentrations of pyridine is well-accounted for simply by applyingthe Nernst equation to the overall reaction. However, while proton transfer can explain the potentials ofthe CV waves in the presence of added pyridine, simulations of the voltammetry show that proton transferby itself cannot explain the observed reversibility of the second oxidation wave in the presence ofincreasing amounts of added pyridine. This is where H-bonding can play a role. By including H-bondingsteps, and allowing electron transfer and proton transfer to occur through the H-bond complex formedbetween H 2 PD + /pyr and HPD + /Hpyr + , the simulations nicely explain both the observed potential shifts andthe reversibility of the waves. The next question is whether the electron and proton transfer within the H-bonding complex is concertedor step wise. To test this, CV’s were run with 10:1 cyanopyridine:H2PD in 2% D 4 -methanol/acetonitrile or2% H 4 -methanol/acetonitrile. If the second oxidation involved concerted electron-proton transfer, asignificant deuterium isotope effect would be expected, causing a larger ΔE p in the deuterated solventresulting from slower electron transfer. However, no significant difference was observed. Therefore,there is no evidence that the electron-proton transfer is concerted. This result does not by any meansrule out the hypothesis that the proton-electron transfer is occurring within the H-bond complex, it merelyindicates that it is likely that the proton and electron transfer occur in a step-wise fashion within the H-bond complex, and that facilitation of proton-electron transfer by H-bonding can happen even if theprocess is not concerted.

Evaluating the Roles of Proton Transfer and H-Bonding in the Electron Transfer Reactions of Organic Redox Couples in Non-Aqueous Solvents: Oxidation of Phenylenediamines in the Presence of Added Bases in Acetonitrile

Oxidation or reduction of organic redox couples typically leads to large changes in acidity or basicity, with the result that proton transfer often accompanies electron transfer, particularly in aqueous solution. In less polar organic solvents, H-bonding also can play an important role. While it is generally appreciated that proton transfer will have a greater effect on the overall reaction than H-bonding, it is not always straight forward to distinguish between the two, and, despite a considerable amount of research, a complete, quantitative understanding of the relative roles that the two play in the voltammetry that is observed upon addition of acids or bases to organic redox couples in non-aqueous solution remains elusive. Most of the research in this area has been done with quinones in the presence of H-donors. In contrast, this study focuses on p-tetramethylphenylenediamine, H2PD, in the presence of H-acceptors. While quinones undergo two successive reductions to form the increasingly basic radical anion, then dianion, phenylenediamines, which are weakly basic to begin with, undergo two successive oxidations to form an increasingly acidic radical cation, then quinoidal dication. Upon addition of DMF, a weak H-acceptor, to H2PD in acetonitrile, small negative shifts in potential of the second oxidation are observed in the cyclic voltammetry (CV), with little change in wave shape. This is consistent with H-bonding of the DMF to the quinoidal dication, H2PD2+. Somewhat similar behavior is observed when slightly more basic guests are added such as cyanopyridine or trifluoromethylpyridine, but, unlike with DMF, with just 1 equivalent pyridine guest, a significant shift in the potential of the second oxidation is observed, followed by smaller shifts with additional equivalents. We believe that this behavior signals proton transfer between the pyridine, pyr, and the H2PD2+, so that the overall reaction occurring in the second oxidation corresponds to H2PD+ + pyr = HPD+ + Hpyr+ + e- . In this case, the observed E1/2 should depend on the pKa of the Hpyr+. To test this hypothesis, the voltammetry of H2PD is currently being studied with different pyridines that cover a range of pKa values. If correct, the explanation for the continued shift in potential with increasing concentrations of pyridine is well-accounted for simply by applying the Nernst equation to the overall reaction. However, while proton transfer can explain the potentials of the CV waves in the presence of added pyridine, simulations of the voltammetry show that proton transfer by itself cannot explain the observed reversibility of the second oxidation wave in the presence of increasing amounts of added pyridine. This is where H-bonding can play a role. By including H-bonding steps, and allowing electron transfer to occur through the H-bond complex formed between H2PD2+ and pyr (the intermediate in the proton transfer), the simulations can nicely explain both the observed potential shifts and the reversibility of the waves.

Direct Synthesis of Trichloro‐thiazolo[3,2‐a]pyrimidine and Thiazolo[2,3‐b]quinazoline Derivatives

An efficient one‐pot method for synthesis of new biologically active thiazolo[3,2‐a]pyrimidine and thiazolo[2,3‐b]quinazoline derivatives is described via reaction of pentachloropyridine with fused pyrimidine‐2(5H)‐thiones or quinazoline‐2(1H)‐thiones. These reactions were carried out in the presence of potassium carbonate as a base in acetonitrile as a solvent to produce products 3a–n in good‐to‐excellent yield. Pentachloropyridine is doubly electrophilic building blocks for the formation of ring annulated thiazolo[3,2‐a]pyrimidine and thiazolo[2,3‐b]quinazoline products.

Dinuclear PdII/PtII complexes [M2(phosphine)n(thio-ligand)3]Cl incorporating N,S-bridged pyridine-2-thiolate and benzimidazoline-2-thiolate

Equimolar reaction of [PdCl2(dppm)] {dppm=bis(diphenylphosphino) methane} with pyridine-2-thione (pySH) in presence of NaOH base in aqueous ethanol formed dinuclear mixed-ligand complex, [PdII2(μ-κ2:N,S-pyS)3(μ-P,P-dppm)]Cl 1. Similarly, reaction of PdCl2(PPh3)2 with benzimidazoline-2-thione (bzimSH) in 1:2M ratio in the presence of Et3N base in acetonitrile has formed a dinuclear complex, [PdII2(μ-κ2:N,S-bzimS)2(κ1-S-bzimS)(PPh3)3]Cl·2H2O 2. Surprisingly, analogous thio-ligand, 1,3-imidazoline-2-thione (imzSH), merely formed a simple square planar complex, [Pd(κ1-S-imzSH)4]Cl2·2H2O 3. The reaction of H2PtCl6 with pySH and dppm (1:1:1M ratio) in the presence of Et3N base in toluene–ethanol (1:1:: v/v) mixture also formed a mixed-ligand dinuclear complex [PtII2(μ-κ2:N,S-pyS)3(μ-P,P-dppm)]Cl similar to 1. All these complexes have been characterized using analytical data, IR, NMR (1H, 31P), UV–vis, fluorescence, ESI-mass and single crystal X-ray crystallographic techniques. The anionic thio-ligands are N,S-bridged in complexes 1 and 4, both N,S-bridged and κ1-S bonded in 2 and as neutral κ1-S bonded in 3. There are short M⋯M contacts in 1 and 4 (1: 2.7249(5) Å; 4: 2.7350(8) Å). Complexes 1, 3 and 4 showed intense fluorescence. ESI mass spectral studies of 1, 3 and 4 revealed the formation of molecular ions and other species.

ChemInform Abstract: Synthesis of New α‐Trifluoromethyl Substituted Formamidines Framework by Using N‐Nucleophiles and N,S Bidentate Nucleophiles.

Abstract An efficient and convenient method for the preparation of new trifluoromethylated benzimidazole, imidazole and benzothiazole derivatives in excellent yields via reaction of N -aryl-2,2,2-trifluoroacetimidoyl chlorides with benzimidazole or benzothiazole or imidazole derivatives in the presence of NaH or NEt 3 as a base in acetonitrile or THF without assistance of any catalyst has been reported. Also nucleophilic substitution of N -aryl-2,2,2-trifluoroacetimidoyl chlorides with unequal N and S bidentate nucleophiles occurred at N position. The FT-IR, 19 F NMR, 1 H NMR, 13 C NMR, UV spectra and elemental analysis confirm the structures of the products.

Synthesis of new α-trifluoromethyl substituted formamidines framework by using N-nucleophiles and N,S bidentate nucleophiles

An efficient and convenient method for the preparation of new trifluoromethylated benzimidazole, imidazole and benzothiazole derivatives in excellent yields via reaction of N-aryl-2,2,2-trifluoroacetimidoyl chlorides with benzimidazole or benzothiazole or imidazole derivatives in the presence of NaH or NEt3 as a base in acetonitrile or THF without assistance of any catalyst has been reported. Also nucleophilic substitution of N-aryl-2,2,2-trifluoroacetimidoyl chlorides with unequal N and S bidentate nucleophiles occurred at N position. The FT-IR, 19F NMR, 1H NMR, 13C NMR, UV spectra and elemental analysis confirm the structures of the products.