Journal of Chemical Sciences最新文献

A series of 1-carbonyl-1H-indoles were prepared by 2-iodoanilines and calcium carbide in a one-pot reaction catalyzed by recyclable10% Pb/C, resulting in the corresponding substituted indoles in good yields. This protocol offers several advantages, including the utilization of sustainable, low-cost calcium carbide, an easy-to-handle acetylene source, and recyclable Pb/C catalysts.

Graphic abstract

The synthesis of a series of 1-carbonyl-1H-indoles were prepared by 2-iodoanilines and calcium carbide in a one-pot reaction catalyzed by 10% Pb/C, resulting in the corresponding substituted indoles in good yields. This protocol offers several advantages, including the utilization of sustainable, low-cost feedstock, an easy-to-handle acetylene source, and recyclable Pb/C catalysts.

Quinoline-based “turn-on” fluorescent probe was successfully synthesized using 5-amino quinoline and 2-(phenylselanyl)benzaldehyde. The probe was found to be selective for superoxide over other reactive oxygen species (ROS) and biothiols. The probe can detect superoxide in the presence of other ROS and biothiols. The detection limit of the probe for superoxide was found to be 37 nM with a Stokes shift of 150 nm. The probe quickly detects superoxide with a 21-fold increase in fluorescence intensity. The probe exhibited anticancer activity on HeLa cells that was comparable to the standard drug (Cisplatin).

Graphical abstract

Organoselenium based quinoline probe was developed. The probe was selective for superoxide with instant response and possess good anticancer activity.

The π-binding of iron tricarbonyl, Fe(CO)₃, tripod is known to effectively alter the stereoselectivity and torquoselectivity of electrocyclic ring opening (ERO) of cyclobutene and its derivatives by changing the mechanism. Representative examples of pseudopericyclic and also borderline pericyclic ERO reactions were chosen for the present study to establish the role of Fe(CO)₃ in manipulating the reactions. The parameters like nucleus-independent chemical shift (NICS), natural bond orbital (NBO) analysis, and topological parameters like ∇²ρ(r) (Laplacian) and ε (ellipticity) have revealed marked drifting of the reaction lying on the pseudopericyclic end to the borderline pericyclic end, which is due to Fe(CO)₃ binding.

Graphical abstract

Iron tricarbonyl alters the nature of pseudopericyclic reaction by making it borderline pericyclic. Activation barrier increases for pseudopericyclic case which is very low in the absence of Fe(CO)_3. No disconnection of orbitals is observed for pseudopericyclic system when complexed with Fe(CO)₃.

Three new palladium(II)-iminophosphine complexes, [Pd(L1)(Cl)₂] C1, [Pd(L2)(Cl)₂] C2 and [Pd(L3)(Cl)₂] C3 have been synthesized and successfully characterized by using ¹H-NMR, ¹³C-NMR, ³¹P-NMR, UV–Vis, FT-IR and magnetic susceptibility techniques. Catalytic activities of complexes towards Suzuki–Miyaura C–C coupling reactions between phenylboronic acid and several aryl halides were investigated under several reaction conditions (solvent, temperature, base, reaction time, and type of substrate). Under optimum conditions, achieving high yields of up to 99% was possible. When 1-bromo-4-nitrobenzene was used for complex C1, bromobenzene for complex C2, and bromobenzene for complex C3, product yields of 99, 99, and 98% were achieved, respectively.

Graphical abstract

Three new palladium complexes bearing iminophosphine ligands was synthesized and successfully characterized. Catalytic activities of the synthesized complexes were investigated on Suzuki–Myaura type coupling reaction between phenylboronic acid and several aryl halides. All complexes exhibited good catalytic activities on C–C coupling reactions up to 99% product formations under mild conditions.

Enzymes are biological catalysts that accelerate chemical reactions by reducing their activation energy. Enzymes specific environmental conditions to function optimally. Additive molecules and compounds, such as organic solvents, ionic liquids, and deep eutectic solvents, have crucial effects on enzyme behavior by changing activity and stability. However, finding and testing different additives is an expensive process that requires specialists, laboratory equipment, and chemical compounds. Machine learning, which has been present in all fields of science and technology in recent years, is one of the ways to find a suitable additive for our desired enzyme without doing a time-consuming experimental process. In this manuscript, we introduce ADDZYME, a machine learning-based software, to predict the effect of additives on enzyme activity. ADDZYME utilizes an ensemble of extremely randomized trees models alongside physicochemical descriptors to make a prediction. To ease usage, ADDZYME is accompanied by a graphical user interface. ADDZYME is freely available on www.github.com/miladrayka/addzyme for further experiments.

Graphical abstract

SYNOPSIS: ADDZYME software applies a machine-learning algorithm to predict the effect of an additive on an enzyme activity. ADDZYME utilizes an ensemble of extremely randomized trees models alongside physicochemical descriptors to make a prediction.

Ammonia (NH₃) is a pyramidal symmetric top molecule with inversion motion and it exists in two distinct nuclear spin isomeric forms, ortho-NH₃ (K = 3n) and para-NH₃ (K ≠ 3n). Here, a pair of electric dipole-allowed [^RQ(4,3) and ^PP(2,2)] and weak forbidden [^OP(3,3) and ^SQ(8,1)] transitions of gas-phase NH₃ were probed in the ν₄ fundamental vibrational band occurring at 6.2 µm mid-IR interference-free spectral region using an external-cavity quantum cascade laser coupled cavity ring-down spectrometer. We have experimentally achieved the ortho-to-para ratio (OPR) of (1.03 ± 0.24) and (1.08 ± 0.14) at room temperature (296 K) for the allowed and forbidden transitions of NH₃, respectively. Furthermore, our experimental findings confirm that the nuclear spin-symmetry is conserved under the nonreactive perturber-induced collisional processes. This study paves the way to directly probe the nuclear spin-isomers of gas-phase NH₃ and thus may lead to an in-depth understanding of nuclear spin-isomerism associated with various physical and chemical processes.

Graphical Abstract

This work shows the high-resolution probing of ortho- and para-nuclear spin-isomers of NH₃ in the gas phase at room temperature using quantum cascade laser coupled cavity ring-down spectroscopy at 6.2 µm mid-IR spectral region.

Sodium borohydride induces the oxidative expansion of the imine derived from isatin and phenylethylamine to form 3-phenethylquinazoline-2,4(1H,3H)-dione. It has been proposed that this transformation occurs by in situ formation of hydroperoxyl anions by a reaction between sodium borohydride and atmospheric oxygen. To contribute to understanding this oxidative expansion, the reaction between the imine derived from isatin and phenylethylamine with hydrogen peroxide was studied in this work. From this reaction, 3-phenethylquinazoline-2,4(1H,3H)-dione was isolated and two by-products were identified: N-phenethyl-2-(3-phenethyl-ureido)-benzamide and methyl(2-(phenethylcarbamoyl)phenyl)carbamate. This article analyses the structure of these by-products and proposes a mechanism that explains the reaction.

Graphical abstract

It was established that the reaction of the imine derived from isatin and phenylethylamine with hydrogen peroxide produces a mixture of three compounds: 3-phenethylquinazoline-2,4(1H,3H)-dione, N-phenethyl-2-(3-phenethyl-ureido)-benzamide and methyl(2-(phenethylcarbamoyl)phenyl)carbamate. A reaction mechanism is proposed that explains this behaviour