The Front Cover highlights 9,9‐difluoro‐3‐azabicyclo3.3.1alkane – a promising novel fluorinated three‐dimensional piperidine isostere. While this parent compound seems to enjoy its well‐deserved ...position in the medicinally relevant chemical space (shown as the peaceful and calm night sky above Kyїv city), many other similar building blocks just synthesized by Ukrainian chemists pave their way into future drug discovery projects, which is shown symbolically as the Quay of Dnipro, the main river in Ukraine. Background photo by Oleksandr Liashuk. More information can be found in the Research Article by O. O. Grygorenko et al.
Several compounds between 2-(2-adamantyl)piperidines, 3-(2-adamantyl)pyrrolidines and 2-(2-adamantylmethyl)piperidines were potent against influenza A H
3N
2 virus. The diamine derivatives
21e–
g and ...particularly
35a–
c possessing three pharmocophoric groups, the adamantanyl and the two amine groups, exhibited high potency. Parent structures
11 and
27 adopt a fixed
trans conformation around C2
C2′ bond. The different shape and distance between nitrogen and adamantyl pharmacophoric groups of the bioactive parent amines
11,
27, and
30 suggest that the influenza virus A receptor can accommodate different in size and orientation lipophilic cages.
The broad-spectrum antiviral activity of 2-(2-adamantyl)piperidines
11,
13a,
b, and
15, 3-(2-adamantyl)pyrrolidines
27,
21a–
g and 2-(2-adamantylmethyl)piperidines
30,
32a–
c, and
35a–
d was examined. Several compounds in the new series were potent against influenza A H
3N
2 virus. When 1-aminoethyl pharmacophore group of 2-rimantadine
4 (2-isomer of rimantadine) is included into a saturated nitrogen heterocycle, see compound
11, potency was retained. The diamine derivatives
21e–
g and particularly
35a–
c possessing three pharmocophoric groups, that is, the adamantyl and the two amine groups, exhibited high potency. The new compounds did not afford specific activity at non-toxic concentrations against any of the other viruses tested. According to NMR spectroscopy and molecular mechanics calculations it is striking that the parent structures
11 and
27 adopt a fixed
trans conformation around C2
C2′ bond. In the parent amines, which proved to be active compounds, the distance between nitrogen and adamantyl pharmacophoric groups was different; N
C2′ distance is 3.7, 3.8
Å for
27,
30 and 2.5
Å for
11 suggesting that M2 receptor site can accommodate different in size and orientation lipophilic cages.
A sequence of seven reactions (stereocontrolled allylation, Mitsunobu reaction, ring closing metathesis, and amino/amido intramolecular nucleophilic addition) efficiently convert the inexpensive ...starting 2‐piperidine ethanol into a small library of enatiomerically pure nitrogen containing compounds characterized by three new scaffolds that present a relevant diversity. This simple approach encroaches the further exploration of the chemical space.
Efficient conversion of 2‐piperidine ethanol into a small library of enantiomerically pure nitrogen containing compounds by a stereodivergent approch is described.
Piperidine is a saturated heterocyclic ring, considered as a privileged scaffold in view of its role in wide range of biological activities. Piperidine is good candidate molecule for obtaining potent ...antioxidant agents. The planar nature of this heterocyclic nucleus allows the introduction of substituent groups at different positions on the ring. In the present review, the antioxidant profile of piperidine containing compounds has been focused. The compounds were classified into naturally occurring piperidines, unsaturated piperidines, N-substituted piperidines, piperamides, piperanols, piperidine oximes, and hydrazides.
Synthesis of monoprotected diamines derived from 1,5‐disubstituted spiro2.3hexane and 5‐azaspiro2.3hexane scaffolds is described. In both cases, the method relied on the cyclopropanation of the ...corresponding cyclobutane or azetidine derivatives. In the case of monoprotected 1,5‐diaminospiro2.3hexanes, the title products were obtained as single diastereomers. X‐Ray diffraction studies supported by exit vector plot (EVP) analysis showed that the obtained building blocks are promising piperidine/cycloalkane isosteres with potential utility to drug discovery. Also, conformations observed in the crystalline state for the two different diastereomers of 1,5‐diaminospiro2.3hexane derivatives prompt their application in design of β‐turn and sheet‐like peptidomimetics, respectively.
Stable and soluble redox‐active nitroxyl radicals are highly desired for high‐capacity and long‐life aqueous zinc hybrid flow batteries (AZHFBs). Here we report a “π–π” conjugated imidazolium and ...“p–π” conjugated acetylamino co‐functionalized 2,2,6,6‐tetramethylpiperidine‐N‐oxyl (MIAcNH‐TEMPO) as stable catholyte for AZHFBs. The incorporation of double‐conjugate substituents could delocalize the electron density of the N−O head and thus remarkably stabilize the radical and oxoammonium forms of TEMPO, avoiding the side reaction of ring‐opening. Consequently, the applied MIAcNH‐TEMPO/Zn AZHFB demonstrates the hardly time‐dependent stability with a constant capacity retention of 99.95 % per day over 16.7 days at a high concentration catholyte of 1.5 M and high current density of 50 mA cm−2. This proposed molecular engineering strategy based on electron density regulation of redox‐active structures displays an attractive efficacy and thus represents a remarkable advance in high‐performance AZHFBs.
An acetylamino and imidazole co‐functionalized 2,2,6,6‐tetramethylpiperidine‐N‐oxyl (MIAcNH‐TEMPO) catholyte for aqueous zinc hybrid flow batteries (AZHFBs) is reported. The “p–π” and “π–π” double‐conjugate structure design delocalizes the electron density of the N−O head and thus inhibits electrophilic/nucleophilic attacks corresponding to N−O⋅/+N=O forms. The applied 1.5 M MIAcNH‐TEMPO‐based AZHFB exhibits a high capacity retention rate of 99.95 % per day at 50 mA cm−2.
An approach to gem‐difluoro‐3‐azabicyclo3.n.1alkane‐ derived building blocks through double‐Mannich addition– deoxofluorination sequence is described. The scope of the method was demonstrated for a ...series of saturated (hetero)cyclic ketones or ketoesters (including five‐ to seven‐membered cycloalkane derivatives and N‐, O‐, S‐containing saturated heterocycles). Further transformations of functional groups produced various bifunctionalized difluorinated building blocks, namely, N‐protected aminoacids, mono‐N‐Boc‐protected diamines, and unprotected aminoalcohols in good to excellent overall yields. For the azabicyclo3.3.1alkane series, a potential for isosteric replacements is demonstrated by evaluation of the key physicochemical properties (i. e., pKa(H) and LogP).Dedicated to the people of Ukraine
The ring expansion of prolinols via an aziridinium intermediate gives C3‐substituted piperidines in good yields and enantiomeric excess, the substituent at the C3 position being derived from the most ...reactive nucleophile in the reaction mixture. Depending on the nucleophile, the reaction proceeds under thermodynamic or kinetic control. The regioselectivity of attack of nucleophiles on the aziridinium intermediate depends on the nature of the substituents on the nitrogen atom and the C4 position of the starting prolinols.
One‐carbon expansion: The ring expansion of enantiomerically pure prolinols via an aziridinium intermediate, either under thermodynamic or kinetic control, gives C3‐substituted piperidines in good yields and enantiomeric excess.
•YVO4:Eu3+ nano-phosphors with a narrow distribution were successfully synthesized via combustion method.•The effects of piperidine (C5H11N) and isobutyl nitrite (C4H9NO2) fuels were compared for the ...first time.•The XRD and TGA spectra of the synthesized luminescent materials revealed that the use of isobutyl nitrite fuel gives rise to higher crystallinity.•The photoluminescence emission of YVO4:Eu3+under 307 nm revealed that the obtained emission intensity by the use of isobutyl nitrite fuel is higher than that of materials synthesized by piperidine.
In this research, the fuels of piperidine (C5H11N) and isobutyl nitrite (C4H9NO2) were used to produce YVO4:Eu3+ nanoparticles. To remove the remaining organic materials and also to improve the crystal structure, these materials were calcined at 800 and 1000 °C, and then the particle size and morphology of the synthesized nanostructures were monitored using a scanning electron microscope (SEM). It was found that the type of consumed fuel and also the calcination temperature result in significant effects on the morphology of the nanostructures as well as the obtained luminescence properties. The use of isobutyl nitrite and piperidine leads to synthesis of homogeneous powders with particle sizes of 38 and 100 nm, respectively. The Rietveld calculations revealed that the growth of the mentioned particles through calcination at 800 °C leads to a reduction of microstrains from 0.00137 to 0.00048 and 0.00126 to 0.00044, respectively. The exciting of these materials by the wavelength of 307 nm causes the creation of a powerful emission spectrum with the highest intensities at the wavelengths of 594 and 624 nm, which originate from the electron transitions of 5D0–7F1 and 5D0–7F2, respectively. Also, the photoluminescence emission of phosphors synthesized by isobutyl nitrite is higher than that of piperidine, which this phenomenon is consistent with X-ray diffraction (XRD) and thermo-gravimetric analysis (TGA) results which proved that the crystallinity of the phosphors synthesized by isobutyl nitrite is higher than that of piperidine.
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