Synthesis, Characterization, X-ray Crystallography, Acetyl Cholinesterase Inhibition and Antioxidant Activities of Some Novel Ketone Derivatives of Gallic Hydrazide-Derived Schiff Bases

The electrochemical oxidation of a sacrificial metal anode (M = Zn, Cd, Cu) in an acetonitrile solution of 2-hydroxy-3-(3-methyl-2-butenyl)-1,4-naphthoquinone, lapachol, C15H14O3 (=HL) gives ML2. The results are in keeping with earlier work on direct electrochemical synthesis in related systems. Adducts with 2,2′-bipyridine (bpy) and N,N,N′,N′-tetramethylethanediamine (tmen) have also been prepared. The structure of the 2,2′-bipyridine adduct of Cu(lapacholate)2 has been established by X-ray crystallography. The parameters are triclinic, space group [Formula: see text], a = 12.748(59) Å, b = 13.859(49) Å, c = 11.770(59) Å, α = 108.30(4)°, β = 108.08(3)°, γ = 68.94(3)°, Z = 2, R = 0.059 for 2256 unique reflections. The copper atom is in a distorted CuN2O2O2′ environment. The mechanism of the formation of this Cu(lapacholate)2 is discussed. Keywords: electrochemical synthesis, lapachol, X-ray crystallography, copper(II) complex.

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Triazene derivatives of (1,x-)diazacycloalkanes. Part VI. 3-({5,5-Dimethyl-3-[2-aryl-1-diazenyl]-1-imidazolidinyl}methyl)-4,4-dimethyl-1-[2-aryl-1-diazenyl]imidazolidines — Synthesis, characterization, and X-ray crystal structure

Canadian Journal of Chemistry ◽

10.1139/v06-091 ◽

2006 ◽

Vol 84 (10) ◽

pp. 1294-1300 ◽

Cited By ~ 1

Author(s):

Keith Vaughan ◽

Shasta Lee Moser ◽

Reid Tingley ◽

M Brad Peori ◽

Valerio Bertolasi

Keyword(s):

Crystal Structure ◽

Significant Degree ◽

Ion Trapping ◽

Published Data ◽

X Ray ◽

X Ray Crystallography ◽

Diazonium Ion ◽

Derivatives Of ◽

C Nmr

Reaction of a series of diazonium salts with a mixture of formaldehyde and 1,2-diamino-2-methylpropane affords the 3-({5,5-dimethyl-3-[2-aryl-1-diazenyl]-1-imidazolidinyl}methyl)-4,4-dimethyl-1-[2-aryl-1-diazenyl]imidazolidines (1a–1f) in excellent yield. The products have been characterized by IR and NMR spectroscopic analysis, elemental analysis, and X-ray crystallography. The X-ray crystal structure of the p-methoxycarbonyl derivative (1c) establishes without question the connectivity of these novel molecules, which can be described as linear bicyclic oligomers with two imidazolidinyl groups linked together by a one-carbon spacer. This is indeed a rare molecular building block. The molecular structure is corroborated by 1H and 13C NMR data, which correlates with the previously published data of compounds of types 5 and 6 derived from 1,3-propanediamine. The triazene moieties in the crystal of 1c display significant π conjugation, which gives the N—N bond a significant degree of double-bond character. This in turn causes restricted rotation around the N—N bond, which leads to considerable broadening of signals in both the 1H and 13C NMR spectra. The molecular ion of the p-cyanophenyl derivative (1b) was observed using electrospray mass spectrometry (ES + Na). The mechanism of formation of molecules of type 1 is proposed to involve diazonium ion trapping of the previously unreported bisimidazolidinyl methane (13).Key words: triazene, bistriazene, imidazolidine, synthesis, X-ray crystallography, NMR spectroscopy.

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Preparation, Characterisation, Crystal Structure and Antibacterial Activity of two Bis-Schiff Bases Containing a Piperazine Ring

Journal of Chemical Research ◽

10.3184/174751918x15383854898654 ◽

2018 ◽

Vol 42 (10) ◽

pp. 512-514

Author(s):

Rui-bo Xu ◽

Xiao-tian Yang ◽

Hai-nan Li ◽

Peng-cheng Zhao ◽

Jiao-jiao Li ◽

...

Keyword(s):

Crystal Structure ◽

Escherichia Coli ◽

Staphylococcus Aureus ◽

Antibacterial Activity ◽

Bacillus Subtilis ◽

Schiff Bases ◽

Piperazine Ring ◽

X Ray ◽

X Ray Crystallography ◽

Good Antibacterial Activity

Two new bis-Schiff bases containing a piperazine ring, N,N‘-bis(4-chlorobenzylidene)- and N,N‘-bis(4-cyanobenzylidene)-1,4-bis(3-aminopropyl)piperazine, were prepared by the reaction of N,N‘-bis(3-aminopropyl)piperazine with 4-chloro- and 4-cyanobenzaldehyde, respectively. The dichloro compound was fully identified by X-ray crystallography and it exhibited good antibacterial activity against Escherichia coli, Staphylococcus aureus and Bacillus subtilis.

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NMR and X-ray studies of apetalic acid isolated from Calophyllum brasiliense and of its chiral amides

Canadian Journal of Chemistry ◽

10.1139/cjc-2021-0163 ◽

2021 ◽

Author(s):

Marie-Rose Van Calsteren ◽

Ricardo Reyes-Chilpa ◽

Chistopher K Jankowski ◽

Fleur Gagnon ◽

Simón Hernández-Ortega ◽

...

Keyword(s):

Antimycobacterial Activity ◽

Side Chain ◽

Carboxyl Group ◽

X Ray Diffraction ◽

Rain Forests ◽

X Ray ◽

X Ray Crystallography ◽

Calophyllum Brasiliense ◽

Derivatives Of

The tropical tree Calophyllum brasiliense (Clusiaceae) grows in the rain forests from Brazil to Mexico. Its leaves, as well as those of other Calophyllum species, are rich sources of chromanone acids, such as apetalic acid, isoapetalic acid, and their derivatives. Apetalic acid has shown significant antimycobacterial activity. The biological activity of apetalic acid has been related to the configuration of three asymmetric centers and the stereochemistry of the molecule; however, the C-19 configuration in the acidic side chain has not been fully resolved. For this reason, the unequivocal determination of the absolute configuration by means of X-ray crystallography in a sample of unique homogeneous apetalic acid stereoisomer was the most important point to start this study. We prepared some chiral amides using the carboxyl group. We determined the C-19 stereochemistry of apetalic acid, and its specific chiral derivatives, using NMR, X-ray diffraction methods, and molecular mechanics. Finally, we observed that steric hindrance in the side chain of apetalic acid leads to restriction of rotation around the pivotal link C-10 and C-19 establishing chiral centers at C2(R), C3(S), and C19(R). We were able to separate derivatives of these two high-rotatory-barrier conformers of apetalic acid by forming diastereoisomeric amides with phenylglycine methyl ester having a chiral center at C-2’. Our results allowed the conclusion of the existence of atropisomerism in the apetalic acid molecule.

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The Conformation of Some 1,6-Disulfide-Bridged D-Hexopyranoses

Australian Journal of Chemistry ◽

10.1071/ch04291 ◽

2005 ◽

Vol 58 (3) ◽

pp. 199 ◽

Cited By ~ 3

Author(s):

Ethan D. Goddard-Borger ◽

Brian W. Skelton ◽

Robert V. Stick ◽

Allan H. White

Keyword(s):

Nmr Spectroscopy ◽

Single Crystal ◽

1H Nmr ◽

1H Nmr Spectroscopy ◽

Similar Investigation ◽

X Ray ◽

X Ray Crystallography ◽

Structure Determinations ◽

Derivatives Of

The use of 1H NMR spectroscopy, in tandem with X-ray crystallography, has cast light on the conformation of the 1,6-disulfide-bridged derivatives of d-gluco-, d-manno-, d-allo-, d-galacto-, and d-talo-pyranose. A similar investigation was performed on the thiosulfinate derived from the d-gluco disulfide. Single-crystal X-ray structure determinations are reported for (1S,5S,6S,7S,8R)-6,7,8-tribenzoyloxy-9-oxa-2,3-dithiabicyclo[3.3.1]nonane, (1S,5S,6S,7R,8R)-6,7,8-tribenzoyloxy-9-oxa-2,3-dithiabicyclo[3.3.1]nonane, and (1S,2S,5S,6S,7S,8R)-6,7,8-triacetoxy-9-oxa-2,3-dithiabicyclo[3.3.1]nonane 2-oxide.

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New insights into chalcogen bonding provided by co-crystal structures of benzisoselenazolinone derivatives and nitrogen bases

CrystEngComm ◽

10.1039/c8ce01853g ◽

2019 ◽

Vol 21 (10) ◽

pp. 1539-1542 ◽

Cited By ~ 3

Author(s):

Thomas Fellowes ◽

Jonathan M. White

Keyword(s):

Crystal Structures ◽

X Ray ◽

Nitrogen Bases ◽

X Ray Crystallography ◽

Derivatives Of

A number of derivatives of benzisoselenazolinones, including the drug ebselen, have been synthesized, and their interactions with various nitrogen bases characterized through X-ray crystallography.

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Interplay of weak noncovalent interactions in alkoxybenzylidene derivatives of benzohydrazide and acetohydrazide: a combined experimental and theoretical investigation and lipoxygenase inhibition (LOX) studies

CrystEngComm ◽

10.1039/d0ce01402h ◽

2021 ◽

Author(s):

Muhammad Naeem Ahmed ◽

Muneeba Arif ◽

Hina Andleeb ◽

Syed Wadood Ali Shah ◽

Ifzan Arshad ◽

...

Keyword(s):

Dft Calculations ◽

Surface Analysis ◽

Schiff Bases ◽

Theoretical Investigation ◽

Noncovalent Interactions ◽

Hirshfeld Surface ◽

X Ray Diffraction ◽

X Ray ◽

Lipoxygenase Inhibition ◽

Derivatives Of

Three hydrazide-based Schiff bases have been synthesized and characterized by IR, UV-vis and X-ray diffraction methods. A detail analysis of intermolecular interactions has been performed by Hirshfeld surface analysis and DFT calculations.

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Application of the Variable Oxygen Probe to Determine the π-Electron Donor Ability of the Alkyne Group

Australian Journal of Chemistry ◽

10.1071/ch14395 ◽

2014 ◽

Vol 67 (12) ◽

pp. 1866 ◽

Cited By ~ 1

Author(s):

Benjamin L. Harris ◽

Jonathan M. White

Keyword(s):

Low Temperature ◽

Electron Donor ◽

Oxygen Probe ◽

X Ray ◽

X Ray Crystallography ◽

Donor Ability ◽

Structural Database ◽

Derivatives Of ◽

Electron Demand ◽

Electron Donor Ability

Eight ester and ether derivatives of propargyl alcohol with varying electron demand were structurally characterised using low temperature X-ray crystallography, these were combined with seven derivatives obtained from the Cambridge Structural Database. Variable oxygen probe analysis of these derivatives provided evidence that the ethynyl substituent is a relatively weak π-electron donor, and is a slightly less effective donor than the C–C bond of an ethyl substituent.

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2-Hetaryl-1,3-tropolones based on five-membered nitrogen heterocycles: synthesis, structure and properties

Beilstein Journal of Organic Chemistry ◽

10.3762/bjoc.11.236 ◽

2015 ◽

Vol 11 ◽

pp. 2179-2188 ◽

Cited By ~ 11

Author(s):

Yury A Sayapin ◽

Inna O Tupaeva ◽

Alexandra A Kolodina ◽

Eugeny A Gusakov ◽

Vitaly N Komissarov ◽

...

Keyword(s):

Density Functional ◽

Acetic Acid Solution ◽

Intramolecular Proton Transfer ◽

Molecular Structures ◽

X Ray Diffraction ◽

Dft Methods ◽

Functional Theory ◽

X Ray ◽

X Ray Crystallography ◽

Derivatives Of

A series of derivatives of 2-hetaryl-1,3-tropolone (β-tropolone) was prepared by the acid-catalyzed reaction of 2-methylbenzoxazoles, 2-methylbenzothiazoles and 2,3,3-trimethylindoline with 3,4,5,6-tetrachloro-1,2-benzoquinone. The molecular structures of the three representative compounds were determined by X-ray crystallography. In crystal and (as shown by the DFT PBE0/6-311+G** calculations) in solution, 2-hetaryl-4,5,6,7-tetrachloro- and 2-hetaryl-5,6,7-trichloro-1,3-tropolones exist in the NH-tautomeric form with a strong resonance-assisted intramolecular N–H···O hydrogen bond. The mechanism of the formation of 1,3-tropolones in the reaction of methylene-active five-membered heterocycles with o-chloranil in acetic acid solution has been studied using density functional theory (DFT) methods. The reaction of 2-(2-benzoxa(thia)zolyl)-5,6,7-trichloro(4,5,6,7-tetrachloro)-1,3-tropolones with alcohols leads to the contraction of the seven-membered tropone ring with the formation of 2-(2-benzoxa(thia)zolyl)-6-alkoxycarbonylphenols. The molecular structure of 2-(2-ethoxycarbonyl-6-hydroxy-3,4,5-trichlorophenyl)benzoxazole has been determined by X-ray diffraction. 2-(2-Benzoxa(thia)zolyl)-6-alkoxycarbonylphenols display intense green fluorescence with anomalous Stokes shifts caused by the excited state intramolecular proton transfer (ESIPT) effects.

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