scholarly journals Anti-Mycobacterium tuberculosis Terpenoids from Resina Commiphora

Molecules ◽  
2019 ◽  
Vol 24 (8) ◽  
pp. 1475 ◽  
Author(s):  
Chuan-Zhi Zhu ◽  
Bin-Yuan Hu ◽  
Jia-Wang Liu ◽  
Yi Cai ◽  
Xin-Chun Chen ◽  
...  
Keyword(s):  
Nmr Spectra ◽  
Human Cancer ◽  
Cycloaddition Reaction ◽  
Diels Alder ◽  
Drug Resistant ◽  
X Ray Diffraction ◽  
Cellular Toxicity ◽  
X Ray ◽  
Human Cancer Cells ◽  
New Compounds

Four new compounds including two new sesquiterpenoid dimers, commiphoroids E (1) and F (2), a new triterpenoid (3), and a new sesquiterpenoid (4), along with three known terpenoids (5−7) were isolated from Resina Commiphora, whose structures were identified by NMR spectra, HRESIMS, and X-ray diffraction analysis. Compounds 1 and 2 both bear an O-bridge ring and feature a plausible [4 + 2] Diels–Alder cycloaddition reaction. Antimycobacterial activities show that all the tested compounds (200 μM) could inhibit the growth of both sensitive and clinically multi-drug resistant (MDR) isolated strains. In addition, cellular toxicity of the isolates against human cancer cells and THP-1 monocyte cells was examined.

Four New Cytotoxic Arborinane-Type Triterpenes from the Endolichenic Fungus Myrothecium inundatum

Planta Medica ◽  
2019 ◽  
Vol 85 (09/10) ◽  
pp. 701-707 ◽  
Author(s):  
Buddha Bahadur Basnet ◽  
Li Liu ◽  
Baosong Chen ◽  
Yerlan Melsuly Suleimen ◽  
Haiyang Yu ◽  
...  
Keyword(s):  
Absolute Configuration ◽  
Ethyl Acetate Extract ◽  
Human Cancer ◽  
Diffraction Experiment ◽  
Human Cancer Cell ◽  
X Ray Diffraction ◽  
X Ray ◽  
Human Cancer Cell Lines ◽  
Endolichenic Fungus ◽  
New Compounds

AbstractTwo new arborinane-type triterpenes, myrotheols A (1) and B (2), two new arborinane-type glycosides, myrothesides C (3) and D (4), together with four known diterpenes (5 – 8) were isolated from the ethyl acetate extract of the endolichenic fungus Myrothecium inundatum. The structures of new compounds 1 – 4 were elucidated by NMR and MS analyses. The absolute configuration of 1 was assigned by a single-crystal X-ray diffraction experiment. Compounds 3 and 4 represent the first two natural 4-O-methyl-α-D-mannosides. Compounds 1 – 8 exhibited cytotoxicity against K562 and RKO human cancer cell lines.

Silaheterocyclen, XXIV. / Silaheterocycles, XXIV.

1993 ◽  
Vol 48 (3) ◽  
pp. 318-332 ◽  
Author(s):  
Norbert Auner ◽  
Armin W. Weingartner ◽  
Eberhardt Herdtweck
Keyword(s):  
Energy Levels ◽  
Cycloaddition Reaction ◽  
Product Distribution ◽  
Diels Alder ◽  
Frontier Molecular Orbitals ◽  
X Ray Diffraction ◽  
Insertion Reactions ◽  
Ene Reaction ◽  
X Ray ◽  
Cycloaddition Product

The 1-amino-2-neopentylsilenes 5-8 are formed in the reaction of LitBu with the aminovinylsilanes 1-4 in n-pentane (addition of LitBu to the vinylic double bond with subsequent 1,2-elimination of LiCl). The α-Li adducts initially formed are trapped by Me3SiOSO2CF3 to yield α-SiMe3-silanes. The silenes undergo insertion reactions into the Si—O bond of Me3SiOMe. In the absence of any trapping reagent dimerization occurs. One of the 1,3-disilacyclobutanes thus formed (15) could be examined by X-ray diffraction. Reacting with 1,3-butadienes the chlorosubstituted silenes 5 and 8 yield [2 + 2]-cycloaddition products. With 1,3-cyclohexadiene Diels-Alder adducts are also obtained, but with cyclopentadiene the [4+2] adducts are formed exclusively. Products of an ene-reaction are observed upon treatment of 2,5-norbornadiene with the silenes 5 and 8.The methylsubstituted silene 6 does not undergo any cycloaddition reaction at all, while from silene 7 only traces of the cycloadducts are produced. Both species mainly yield the dimers. The preference for the [2+2] reaction type, exhibited by the silenes 5 and 8, is due to their polarity. The almost complete absence or low yield of any cycloaddition products from 6 or 7 can be correlated with the energy levels of their frontier molecular orbitals. The distribution of the disilacyclobutanes and cycloaddition product isomers is explained by the characteristics of the stereospecifically Ε-configurated silenes. The product distribution can also be rationalized considering the ambiphilic nature of the system ViRR′SiCl/Li1Bu.

X–Ray Diffraction (XRD), Powder X–Ray Diffraction (PXRD) and Energy–Dispersive X–Ray Diffraction (EDXRD) Comparative Study on Malignant and Benign Human Cancer Cells and Tissues under Synchrotron Radiation

2018 ◽  
Vol 1 (1) ◽  
pp. 1-14 ◽  
Keyword(s):  
Synchrotron Radiation ◽  
Comparative Study ◽  
Cancer Cells ◽  
Human Cancer ◽  
Energy Dispersive ◽  
X Ray Diffraction ◽  
X Ray ◽  
Human Cancer Cells ◽  
Before And After

In the current study, we have experimentally and comparatively investigated and compared malignant human cancer cells and tissues before and after irradiating of synchrotron radiation using X–Ray Diffraction (XRD), Powder X–Ray Diffraction (PXRD) and Energy–Dispersive X– Ray Diffraction (EDXRD).

A Chemoenzymatic Synthesis of the cis-Decalin Core Associated with the Novel Anti-Mitotic Agent Phomopsidin: Some Observations Concerning a High-Pressure-Promoted Diels–Alder Cycloaddition Reaction of (1S,2R)-3-Methyl-cis-1,2-dihydrocatechol and the Anionic Oxy–Cope Rearrangement of Compounds Derived from the Adduct

2004 ◽  
Vol 57 (7) ◽  
pp. 641 ◽  
Author(s):  
Martin G. Banwell ◽  
Alison J. Edwards ◽  
Malcolm D. McLeod ◽  
Scott G. Stewart
Keyword(s):  
Cycloaddition Reaction ◽  
Diels Alder ◽  
Chemoenzymatic Synthesis ◽  
Cope Rearrangement ◽  
The Novel ◽  
X Ray Diffraction ◽  
Enantiomerically Pure ◽  
X Ray ◽  
Wittig Rearrangements ◽  
Rearrangement Reaction

The enantiomerically pure and enzymatically derived cis-1,2-dihydrocatechol 2 engages in a diastereofacially selective Diels–Alder cycloaddition reaction with commercially available lactone 3 at 19 kbar to afford adduct 4, which is readily elaborated to the diene-ol 13. Treatment of this last compound with KH/18[crown]-6 resulted in successive anionic oxy-Cope and 1,2-Wittig rearrangements to afford acyloin 14 embodying the cis-decalin core associated with the natural product phomopsidin (1). Compound 16 also engages in an anionic oxy-Cope rearrangement reaction to give, depending on the molar equivalents of base used, either the cis-decalin 17 or the hexahydroindene 18. The structure of compound 18 has been established by single-crystal X-ray diffraction analysis.

Water Promoted One-pot Three-Step Synthesis of Novel N-Saccharin Isoxazolines/Isoxazoles Using KI/Oxone Under Ultrasonic Activation

2019 ◽  
Vol 23 (11) ◽  
pp. 1270-1281 ◽  
Author(s):  
Hamza Tachallait ◽  
Mohsine Driowya ◽  
Eleuterio Álvarez ◽  
Rachid Benhida ◽  
Khalid Bougrin
Keyword(s):  
Cycloaddition Reaction ◽  
Hydroxylamine Hydrochloride ◽  
Spectroscopic Techniques ◽  
X Ray Diffraction ◽  
Ultrasonic Activation ◽  
One Pot ◽  
Ultrasonic Probe ◽  
X Ray ◽  
X Ray Crystallography ◽  
New Compounds

A green and efficient regioselective protocol was developed for the preparation of novel isoxazolines and isoxazoles of N-saccharin derivatives via the water-promoted cycloaddition reaction of nitrile oxides with alkenes and alkynes. It is noteworthy that KI/Oxone/water-promoted one-pot three-component reactions of aldehyde, hydroxylamine hydrochloride, and alkene or alkyne were observed to be very satisfactory. The synthesis of all adducts (4a-j/5a-j) has been carried out by this method with high to excellent yields (70-95%) at 25°C within 30 min, using ultrasonic probe. All the new compounds were thoroughly characterized by spectroscopic techniques and also 5b, 5c and 5f were structurally identified by single-crystal X-ray diffraction methods. X-ray crystallography structure analysis clearly supported the regioselectivity of the cycloaddition reaction.

scholarly journals [3+2] Cycloaddition Reaction for the Stereoselective Synthesis of a New Spirooxindole Compound Grafted Imidazo[2,1-b]thiazole Scaffold: Crystal Structure and Computational Study

Crystals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 5
Author(s):  
Mezna Saleh Altowyan ◽  
Saied M. Soliman ◽  
Matti Haukka ◽  
Nora Hamad Al-Shaalan ◽  
Aminah A. Alkharboush ◽  
...  
Keyword(s):  
Nmr Spectra ◽  
Stereoselective Synthesis ◽  
Computational Study ◽  
Cycloaddition Reaction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Crystal Stability ◽  
Straight Line ◽  
Td Dft ◽  
Ethylene Derivative

A new spirooxindole hybrid engrafted imidazo[2,1-b]thiazole core structure was designed and achieved via [3+2] cycloaddition reaction approach. One multi-component reaction between the ethylene derivative based imidazo[2,1-b]thiazole scaffold with 6-Cl-isatin and the secondary amine under heat conditions afforded the desired compound in a stereoselective manner. The relative absolute configuration was assigned based on single-crystal X-ray diffraction analysis. Hirshfeld calculations for 4 revealed the importance of the H…H (36.8%), H…C (22.9%), Cl…H (10.4%) and S…H (6.6%), as well as the O…H (4.7%), N…H (5.3%), Cl…C (1.6%), Cl…O (1.0%) and N…O (0.5%) contacts in the crystal stability. DFT calculations showed excellent straight-line correlations (R2 = 0.9776–0.9962) between the calculated and experimental geometric parameters. The compound has polar nature (3.1664 Debye). TD-DFT and GIAO calculations were used to assign and correlate the experimental UV-Vis and NMR spectra, respectively.

The Electron Effect of Aromatic Group: Control Conformation of 2-Aromatic Cyclododecanone Derivatives

2020 ◽  
Vol 24 (10) ◽  
pp. 1139-1147
Author(s):  
Yang Mingyan ◽  
Wang Daoquan ◽  
Wang Mingan
Keyword(s):  
1H Nmr ◽  
13C Nmr ◽  
Nmr Spectra ◽  
Coupling Constants ◽  
The Other ◽  
Repulsive Interaction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electron Effect ◽  
Group Control

2-Phenylcyclododecanone and 2-cyclohexylcyclododecanone derivatives were synthesized and characterized by 1H NMR, 13C NMR, HR-ESI-MS and X-ray diffraction. Their preferred conformations were analyzed by the coupling constants in the 1H NMR spectra and X-ray diffraction, which showed the skeleton ring of these derivatives containing [3333]-2-one conformation, and the phenyl groups were located at the side-exo position of [3333]-2-one conformation due to the strong π-π repulsive interaction between the π- electron of benzene ring and π-electron of carbonyl group. The cyclohexyl groups were located at the corner-syn or the side-exo position of [3333]-2-one conformation depending on the hindrance of the other substituted groups. The π-π electron effect played a crucial role in efficiently controlling the preferred conformation of 2-aromatic cyclododecanone and the other 2-aromatic macrocyclic derivatives with the similar preferred square and rectangular conformations.

Preparation, properties and structure of some intermediate nido- and arachno-monocarbaboranes

1981 ◽  
Vol 46 (10) ◽  
pp. 2345-2353 ◽  
Author(s):  
Karel Baše ◽  
Bohumil Štíbr ◽  
Jiří Dolanský ◽  
Josef Duben
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Nmr Spectra ◽  
Liquid Ammonia ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr ◽  
Starting Compound

The 6-N(CH3)3-6-CB9H11 carbaborane reacts with sodium in liquid ammonia with the formation of 6-CB9H12- which was used as a starting compound for preparing the 4-CB8H14, 9-L-6-CB9H13 (L = (CH3)2S, CH3CN and P(C6H5)3), 1-(η5-C5H5)-1,2-FeCB9H10-, and 2,3-(η5-C5H5)2-2,31-Co2CB9H10- carboranes. The 4-CB8H14 compound was dehydrogenated at 623 K to give 4-(7)-CB8H12 carborane. Base degradation of 6-N(CH3)3-6-CB9H11 in methanol resulted in the formation of 3,4-μ-N(CH3)3CH-B5H10. The structure of all compounds was proposed on the basis of their 11B and 1H NMR spectra and X-ray diffraction was used in the case of the transition metal complexes.

Axially Chiral Bis(α-amino Acid)s and Their Deamino Analogues. Synthesis and Configurational Assignment

1998 ◽  
Vol 63 (2) ◽  
pp. 211-221 ◽  
Author(s):  
Miloš Tichý ◽  
Luděk Ridvan ◽  
Miloš Buděšínský ◽  
Jiří Závada ◽  
Jaroslav Podlaha ◽  
...  
Keyword(s):  
Amino Acid ◽  
Nmr Spectra ◽  
Building Blocks ◽  
X Ray Diffraction ◽  
Amino Groups ◽  
X Ray ◽  
Configurational Assignment ◽  
Symmetry Properties ◽  
Axially Chiral ◽  
Polymeric Structures

The axially chiral bis(α-amino acid)s cis-2 and trans-2 as possible building blocks for polymeric structures of novel type of helicity were prepared. Their configuration has been determined by NMR spectroscopy and, in the case of the trans-isomer, confirmed by single-crystal X-ray diffraction. Analogous pair of stereoisomeric diacids cis-3 and trans-3, devoid of the amino groups, was also prepared and their configuration assigned. The observed differences in the NMR spectra of cis- and trans-isomers of 2 and 3 are discussed from the viewpoint of their different symmetry properties.

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