Nano indium oxide-catalyzed domino reaction for the synthesis of N-alkoxylated benzimidazoles

A mild and convenient protocol for the synthesis of quinoxalin-2(1H)-ones and benzimidazoles

We present a mild and simple method for the cyclization of N-protected o-phenylenediamines with carbonyl compounds in the presence of trifluoroacetic acid. This method reliably provides various substrates of benzimidazoles and quinoxalin-2(1H)-ones, with all reactions conducted at room temperature, demonstrating excellent substrate adaptability and a broad substrate scope.

New azole-derived hemiaminal ethers as promising acetylcholinesterase inhibitors: synthesis, X-ray structures, in vitro and in silico studies

A new class of azole-derived hemiaminal ethers is designed as acetylcholinesterase (AChE) inhibitors. The synthesized compounds exhibited remarkable inhibitory activity against acetylcholine. Chiral hemiaminals (3d and 3i) based on (R)-menthoxymethyl group exhibit excellent inhibition with IC50 values of 0.983 ± 1.41 and 1.154 ± 0.89 µM. Similarly, butoxymethyl derivatives 3a, 3f and 3h, also showed promising inhibition comparable to the standard drug, Donepezil. In silico studies were performed to understand the mode of interactions with the target proteins, where menthoxymethyl azoles 3d and 3i demonstrated the highest docking scores. Molecular dynamics simulations displayed the stable ligand-protein complex of 3i with effective binding interactions. The bioavailability and pharmacokinetic parameterssupported the suitability of these small molecule inhibitors to develop cost-effective drug leads for Alzheimer's disease (AD). MTT assay substantiated the non-cytotoxic nature of the compounds. The synthesized compounds are extensively characterized by 1H NMR, 13C NMR and mass spectral data and SC-XRD.Communicated by Ramaswamy H. Sarma.

Thermodynamics of heterogeneous equilibria in the In-In2 O3 system using Knudsen effusion mass spectrometry

RATIONALE

The In-In₂ O₃ system is regarded as a potential low-temperature source of gaseous indium oxide (In₂ O) when obtaining functional materials by physical vapor deposition techniques. To date the vaporization thermodynamics of the system have been investigated in few studies, the results of which are contradictory.

METHODS

The study of the In-In₂ O₃ system was performed using Knudsen effusion mass spectrometry in the temperature range 930-1210 K, with a magnet mass spectrometer (MS-1301). Quartz effusion cells heated by a resistance furnace were employed.

RESULTS

It was established that In(g) and In₂ O(g) are the major vapor species over heterogeneous mixtures (In(l) + In₂ O₃ (s)) and the gaseous oxide In₂ O is predominant. The partial pressures of the vapor species were determined and the quantitative vapor composition was calculated. Based on the experimental data, a p-x section of the In-In₂ O₃ system phase diagram at 1060 K was constructed. The standard enthalpies of reactions accompanying vaporization of the In and In₂ O₃ mixtures were evaluated using the second- and third-law methods. The standard enthalpy of formation of In₂ O(g) was derived from the enthalpies of reactions obtained.

CONCLUSIONS

The predominance of In₂ O in the equilibrium vapor over heterogeneous mixtures (In(l) + In₂ O₃ (s)), along with its high partial pressure at relatively low temperatures, substantiate the In-In₂ O₃ system to be suitable for physical vapor deposition methods. The obtained results can be used for physical vapor deposition parameter adjustment and optimization. The standard enthalpy of formation of In₂ O(g) obtained in an independent way in the present work is in good agreement with that from our previous In₂ O₃ (s) vaporization study.

Vaporization thermodynamics of In2 O3 by Knudsen effusion mass spectrometry. The standard enthalpy of formation of In2 O(g)

RATIONALE

In₂ O₃ is one of the most important semiconductor oxides in modern electronics. Vacuum deposition methods are often used for the preparation of In₂ O₃ -based nanomaterials. Thus, vaporization thermodynamics is of key importance for process control and optimization. Since the literature data on the vapor composition and partial pressure values for In₂ O₃ are contradictory, vaporization thermodynamics of In₂ O₃ needs to be clarified.

METHODS

Vaporization behavior of In₂ O₃ was studied using the Knudsen effusion technique in the temperature range 1400-1610 K. Quartz effusion cells were employed. A magnet mass spectrometer with an ordinary focus and a sector-type analyzer was used. Heating of samples and molecular beam ionization were performed by electron impact. The operating ionizing electron energy was 75 eV.

RESULTS

A specially designed experiment allowed us to determine the individual mass spectrum of the In₂ O molecule and, thus, to interpret the mass spectrum of the vapor registered during In₂ O₃ vaporization. The composition of the equilibrium vapor was quantified and the partial pressures of the vapor species were determined. On the basis of the experimental data, the standard enthalpies of some gaseous and heterogeneous reactions taking place during In₂ O₃ vaporization and the standard enthalpy of formation of In₂ O(g) were calculated.

CONCLUSIONS

The presence of In species in the vapor over In₂ O₃ was confirmed and the vapor composition was quantified. Thermodynamic characteristics of In₂ O₃ vaporization were obtained and a value of the standard enthalpy of formation of In₂ O(g) was recommended. These data can be used for further thermodynamic calculations and for evaluating parameters for the synthesis and exploitation of In₂ O₃ -containing materials.