An Aza-Piancatelli Templated Reaction Manifold of 4-Aminocyclopentenones Enables Access to Complex Carbocyclic Assemblies

Capitalizing on the propensity of 1, 2-amino group migration in γ-aminocyclopentenone with a suitable promoter, gem-diaryl equipped systems unfolded an unprecedented avenue for the Lewis acid promoted displacement of γ-aniline group with nucleophiles such as indole. Such transformation, besides providing a means for direct γ-functionalization of cyclopentenones, presented innumerable scope for β, γ-annulation. Various tailored indolo bis-nucleophiles were explored in the current study that rendered an array of indole alkaloid-like compounds in excellent yields and selectivity through one-pot operation. Analysis of collective experimental observation along with designed control experiments strongly suggested the possibility of a retro aza-Piancatelli rearrangement, which is hitherto unknown in the context. Such repertoire could find potential applications in the synthesis of complex assemblies from the Piancatelli rearrangement and related processes. 1. Introduction 2. Aza-Piancatelli rearrangement and related domino processes 3. An unprecedented aza-Piancatelli-templated strategy for polycyclic assemblies 4. Summary and Outlook

New Histamine-Related Five-Membered N-Heterocycle Derivatives as Carbonic Anhydrase I Activators

A series of histamine (HST)-related compounds were synthesized and tested for their activating properties on five physiologically relevant human Carbonic Anhydrase (hCA) isoforms (I, II, Va, VII and XIII). The imidazole ring of HST was replaced with different 5-membered heterocycles and the length of the aliphatic chain was varied. For the most interesting compounds some modifications on the terminal amino group were also performed. The most sensitive isoform to activation was hCA I (KA values in the low micromolar range), but surprisingly none of the new compounds displayed activity on hCA II. Some derivatives (1, 3a and 22) displayed an interesting selectivity for activating hCA I over hCA II, Va, VII and XIII.

Study on denitration performance of multi element modified MIL-101 (Fe) at low temperature

MIL-101 (Fe) was modified by amino group and doped by Cu and Co elements by microwave hydrothermal method. The effect of SCR denitrification at low temperature was investigated with high concentration of NOx as adsorption object. The results show that when the flue gas temperature is 200 °C and the NOx concentration is up to 1640 mg/m3, the removal efficiency of NOx can reach 86% under the optimal conditions, which is 1.5 times higher than that before modification. In addition, the characterization results indicated that the specific surface area of the modified catalyst increased, the thermal stability was good at low temperature, the selective adsorption capacity of NO was enhanced, and the doping played a synergistic catalytic role. It can be used for flue gas denitration in various industries.

Synthesis of Fluorenes and Their Related Compounds from Biaryls and Meldrum’s Acid Derivatives

A new synthetic method for preparing fluorenes from amino group-containing biaryls and Meldrum’s acid derivatives was developed. The reaction proceeded without a catalyst and loss of functional groups. The corresponding...

Polyhalogenated aminobenzonitriles vs their co-crystals with 18-crown-6: amino group position as a tool to control crystal packing and solid-state fluorescence

A series of para- and ortho-aminobenzonitriles differing in the nature and number of halogen substituents was used to synthesize 2:1 co-crystals with 18-crown-6 ether. Supramolecular structure of the obtained co-crystals...

Removal of Organic Compounds with an Amino Group during the Nanofiltration Process

The research covered the process of nanofiltration of low molecular weight organic compounds in aqueous solution. The article presents the results of experiments on membrane filtration of compounds containing amino groups in the aromatic ring and comparing them with the results for compounds without amino groups. The research was carried out for several commercial polymer membranes: HL, TS40, TS80, DL from various manufacturers. It has been shown that the presence of the amino group and its position in relation to the carboxyl group in the molecule affects the retention in the nanofiltration process. The research also included the oxidation products of selected pharmaceuticals. It has been shown that 4-Amino-3,5-dichlorophenol—a oxidation product of diclofenac and 4-ethylbenzaldehyde—a oxidation product of IBU, show poor separation efficiency on the selected commercial membranes, regardless of the pH value and the presence of natural organic matter (NOM). It has been shown that pre-ozonation of natural river water can improve the retention of pollutants removed.

Characterization of Aniline Degradation by A Previously Isolated Molybdenum-reducing Pseudomonas sp.

Microorganisms play an integral role in detoxification and removal of toxic compounds from the environment. Aniline is the simplest aromatic amine, consisting of a phenyl group attached to an amino group that is used as herbicide to control weeds. Aniline is detrimental to both environment and health. In this research, six previously isolated bacteria (isolate A-F) were screened on Bushnell Hass media for their potential to grow and utilize aniline as a sole carbon source. Isolate A (Pseudomonas sp.) was found to tolerate and grow best with aniline sole source of carbon. Optimum conditions for aniline degradation by this isolate were found to be pH 6.0, temperature between 30 and 37 °C, inoculums size of 600 μL, aniline concentration of 200 mg/L and incubation time of 96 h. The capacity of this isolate to reduce toxic aniline to less toxic form is novel and makes the bacterium important instrument for bioremediation of this pollutant.

Quantum chemical study on the interaction of arginine with silica surface

The structure and energy characteristics of structures formed during arginine adsorption on silica surface from aqueous solution were studied by the density functional theory (B3LYP) method using a valence-split basis set 6-31++G(d,p) within the continuous solvent model (PCM) and supermolecular approximation. The equilibrium structural and energy parameters of the protonated arginine molecule in the gas phase dependent on the location of the hydrogen atom are considered including those of two possible zwitterions. The structure of the arginine ion Н2А+, which is formed when a proton attaches to a molecule or zwitterion of a given amino acid, has been elucidated. To determine the deprotonation constant of the carboxyl group in an acidic medium, the complexes of the arginine molecule (AH32+) in the state with undissociated and deprotonated carboxyl groups are considered. The simulation of the acid medium was performed by taking into account the interaction with two hydrated HCl ion pairs, which provided the protonation of the a-amino group and the nitrogen atom of amino group within the guanidine group. In the study on the interaction of an arginine molecule with silica surface in an aqueous medium, complexes containing a Si8O12(OH)7O– ion with a deprotonated silanol group, six water molecules, and an arginine molecule with a deprotonated carboxyl group were considered. It has been found that the arginine molecule is most likely to be adsorbed on slica surface with formation of hydrogen bonds between the hydrogen atoms of the a-amino group and the oxygen atom of the deprotonated silanol group. In this case, the formation of a hydrogen bond between the oxygen atom of the carboxyl group and the hydrogen atom of the neighboring silanol group is possible. Slightly less likely is adsorption of arginine molecules due to interaction of the guanidine group with silanol groups of the surface. According to the calculated data, the adsorption of the zwitterionic form of the arginine molecule from the aqueous solution is equally likely to occur due to interaction of silanol groups of silica surface with both the carboxyl group and the guanidine group.

DETERMINATION OF THE STABILITY OF COMPLEX COMPOUNDS OF COPPER (II), ZINC (II), CADMIUM (II) AND SILVER (I) WITH COVALENTLY IMMOBILIZED SULFUR CONTAIN LIGANDS

"The purpose of this study is to determine the stability of the obtained coordination compounds of some d-metals with covalent immobilized sulfur-containing ligands. To achieve this goal, coordination compounds of copper (II), zinc (II), cadmium (II) and silver (I) ions with covalent immobilized sulfur-containing ligands - О,О-di- (2-aminoethyl) -dithiophosphate potassium - polyester matrix (KD2AEDTP-PEM), O,O-di- (2-aminoethyl) -dithiophosphate potassium - carbamide-formaldehyde matrix (KD2AEDTP-KFM). Studies were carried out to determine the acid-base properties of covalent-immobilized sulfur-containing ligands - KD2AEDTP-PEM, KD2AEDTP-KFM and the concentration stability of the obtained coordination compounds with ions of copper (II), zinc (II), cadmium (II), and silver (I). Based on the results of integral and differential potentiometric titrations, it was established that the ionization constants (pK) of the dithiophosphoric group in KD2AEDTP-PEM and KD2AEDTP-KFM are 3.23 and 3.35, and the ionization constants of the amino group are 9.76 and 9.63, respectively. As a result of studies of polymer ligands by potentiometric titration via the method of individual weighed portions, it was shown that polyfunctional polymer ligands have the ability to form stable coordination compounds with metal ions of copper (II), zinc (II), cadmium (II) and silver (I). "