Detailed 1 H and 13 C NMR structural assignment of ent ‐polyalthic acid, a biologically active labdane diterpene

2021 ◽  
Author(s):  
Pedro Y. Kovatch ◽  
Alexsandro E. Ferreira ◽  
Guilherme M. L. Ghizonni ◽  
Sérgio R. Ambrósio ◽  
Antônio E. M. Crotti ◽  
...  
Keyword(s):  
Biologically Active ◽  
Structural Assignment ◽  
Labdane Diterpene ◽  
C Nmr

scholarly journals Design and synthesis of a novel 5-(aminomethylene)thiazolidine-2,4-dione derivatives as potent hepatitis-B virus polymerase inhibitors

2015 ◽  
Vol 10 (2) ◽  
pp. 271
Author(s):  
Wei-Guo Li ◽  
He-Qun Wang
Keyword(s):  
Hbv Dna ◽  
Biologically Active ◽  
Secondary Amines ◽  
Design And Synthesis ◽  
H Nmr ◽  
Viral Antigens ◽  
Polymerase Inhibitors ◽  
Potent Inhibition ◽  
B Virus ◽  
C Nmr

<p>A series of novel thiazolidinedione analogues (TZD) were designed and synthesized potent inhibitors of HBV capsid assembly. The synthesis of thiazolidine-2,4-dione derivatives (4a–4o), starting from the condensation of 5-(ethoxymethylene)thiazolidine-2,4-dione (1) with various secondary amines (3) derived from biologically active compounds. The newly synthesized TZD analogues 4a-4o were characterized by <sup>1</sup>H NMR, <sup>13</sup>C NMR, and MS and evaluated for their anti-HBV activity. Most of the compounds inhibited the expression of viral antigens at low concentration. Six compounds, 4g, 4h, 4l, 4m, 4n, and 4o, demonstrated potent inhibition of HBV DNA replication at submicromolar range. Of these five initial hits, compound 4o was the most active when compared with lamivudine.</p><p> </p><p> </p>

Detailed 1H and 13C NMR structural assignment of three biologically active lignan lactones

2006 ◽  
Vol 63 (1) ◽  
pp. 234-239 ◽  
Author(s):  
Vladimir Constantino Gomes Heleno ◽  
Rosangela da Silva ◽  
Susimaire Pedersoli ◽  
Sérgio de Albuquerque ◽  
Jairo Kenupp Bastos ◽  
...  
Keyword(s):  
13C Nmr ◽  
Biologically Active ◽  
1H And 13C Nmr ◽  
Structural Assignment

Conformation of ring A in triterpenoid ketones. Carbon-13 chemical shifts and spin-lattice relaxation times of lupane and 18α-oleanane derivatives

1989 ◽  
Vol 54 (7) ◽  
pp. 1928-1939 ◽  
Author(s):  
Miloš Buděšínský ◽  
Jiří Klinot
Keyword(s):  
Chemical Shifts ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Chair Conformation ◽  
Spin Lattice Relaxation ◽  
Spin Lattice ◽  
Structural Assignment ◽  
Boat Form ◽  
The One ◽  
C Nmr

13C NMR spectra of sixteen lupane and 19β,28-epoxy-18α-oleanane triterpenoids I-XVI were measured and a complete structural assignment of chemical shifts was made. For most compounds also the carbon spin-lattice relaxation times T1 were obtained. Characteristic differences in chemical shifts of some carbon atom signals were found between 2α-methyl-3-oxo and 2α-methyl-1-oxo derivatives II, V and VIII with chair conformation of the ring A on the one hand and their 2β-isomers III, VI and IX (boat form) on the other. Using these 2-methyl ketones as models, the chair-boat population in allobetulone (I), 3-oxo-28-lupanenitrile (IV) and 1-oxo derivative VII was determined. The results agree well with the data obtained by other physical methods.

scholarly journals Compounds from the Fruits of the Popular European Medicinal PlantVitex agnus-castusin Chemoprevention via NADP(H):Quinone Oxidoreductase Type 1 Induction

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Shenghong Li ◽  
Shengxiang Qiu ◽  
Ping Yao ◽  
Handong Sun ◽  
Harry H. S. Fong ◽  
...  
Keyword(s):  
Biological Effects ◽  
Cancer Chemoprevention ◽  
2D Nmr ◽  
Biologically Active ◽  
Hydroxybenzoic Acid ◽  
Induction Effect ◽  
Quinone Oxidoreductase ◽  
Labdane Diterpene ◽  
First Time

As part of our continuing efforts in the search for potential biologically active compounds from medicinal plants, we have isolated 18 compounds including two novel nitrogen containing diterpenes from extracts of the fruits ofVitex agnus-castus. These isolates, along with our previously obtained novel compound vitexlactam A (1), were evaluated for potential biological effects, including cancer chemoprevention. Chemically, the nitrogenous isolates were found to be two labdane diterpene alkaloids, each containing anα,β-unsaturatedγ-lactam moiety. Structurally, they were elucidated to be 9α-hydroxy-13(14)-labden-16,15-amide (2) and 6β-acetoxy-9α-hydroxy-13(14)-labden-15,16-amide (3), which were named vitexlactams B and C, respectively. The 15 known isolates were identified as vitexilactone (4), rotundifuran (5), 8-epi-manoyl oxide (6), vitetrifolin D (7), spathulenol (8),cis-dihydro-dehydro-diconiferylalcohol-9-O-β-D-glucoside (9), luteolin-7-O-glucoside (10), 5-hydroxy-3,6,7,4′-tetramethoxyflavone (11), casticin (12), artemetin (13), aucubin (14), agnuside (15),β-sitosterol (16),p-hydroxybenzoic acid (17), andp-hydroxybenzoic acid glucose ester (18). All compound structures were determined/identified on the basis of 1D and/or 2D NMR and mass spectrometry techniques. Compounds6,8,9, and18were reported from aVitexspieces for the first time. The cancer chemopreventive potentials of these isolates were evaluated for NADP(H):quinone oxidoreductase type 1 (QR1) induction activity. Compound7demonstrated promising QR1 induction effect, while the new compound vitexlactam (3) was only slightly active.

scholarly journals Biologically active alkali metal complexones. A13 C-NMR study of ion-dipole interaction

FEBS Letters ◽  
1972 ◽  
Vol 21 (1) ◽  
pp. 34-38 ◽  
Author(s):  
V.F. Bystrov ◽  
V.T. Ivanov ◽  
S.A. Koz'min ◽  
I.I. Mikhaleva ◽  
K.Kh. Khalilulina ◽  
...  
Keyword(s):  
Alkali Metal ◽  
Dipole Interaction ◽  
Biologically Active ◽  
Nmr Study ◽  
C Nmr

scholarly journals Studies of Biologically Active Heterocycles: Synthesis, Characterization and Antimicrobial Activity of Some 5-Substitutd-2-Amino-1,3,4-Oxadiazoles

1970 ◽  
Vol 9 (1) ◽  
pp. 53-59
Author(s):  
Sanjeev Kumar
Keyword(s):  
Antifungal Activity ◽  
Electrochemical Oxidation ◽  
Room Temperature ◽  
Antibacterial Agents ◽  
Antimicrobial Agents ◽  
Biologically Active ◽  
Structural Assignment ◽  
Platinum Anode ◽  
Controlled Potential Electrolysis ◽  
Controlled Potential

In the present study, 5-substituted-2-amino-1,3,4-oxadiazoles (4a-k) have been synthesized by the electrochemical oxidation of semicarbazones (3a-k) using platinum anode at room temperature under controlled potential electrolysis in an undivided cell assembly. The structural assignment of these compounds (4a-k) has been made on the basis of elemental analysis, IR, 1H NMR and 13C NMR. The synthesized compounds were screened for their inhibiting activity against Klebsilla penumoniae, Escherichia coli, Bassilus subtilis and Streptococcus aureus and antifungal activity against Aspergillus niger and Crysosporium pannical and results have been compared with the standard antibacterial agents, Streptomycin and antifungal drug, Griseofulvin. The Compounds exhibited significant antibacterial activity and antifungal activity. Key words: Electrochemical oxidation; controlled potential; 5-substituted-2-amino-1,3,4-oxadiazole; semicarbazone; antimicrobial agents DOI: 10.3329/dujps.v9i1.7434 Dhaka Univ. J. Pharm. Sci. 9(1): 53-59 2010 (June)

scholarly journals Microwave-Assisted Solution Phase Synthesis of Novel 2-{4-[2-(N-Methyl-2-pyridylamino)ethoxy]phenyl}-5-Substituted 1,3,4-Oxadiazole  Library

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
Santosh L. Gaonkar ◽  
Izuru Nagashima ◽  
Hiroki Shimizu
Keyword(s):  
Oxidative Cyclization ◽  
Biologically Active ◽  
Environmentally Benign ◽  
Efficient Catalyst ◽  
Phase Synthesis ◽  
H Nmr ◽  
Solution Phase Synthesis ◽  
Elemental Analyses ◽  
Chloramine T ◽  
C Nmr

A new series of 2-{4-[2-(N-methyl-2-pyridylamino)ethoxy]phenyl}-5-substituted 1,3,4-oxadiazoles were synthesized by the oxidative cyclization of hydrazones derived from 4-[2-(methylpyridin-2-ylamino)ethoxy]benzaldehyde and aryl hydrazines using chloramine-T as an efficient catalyst. All steps were assisted by microwave irradiation. Microwave enables all these reactions to be simple, rapid, high yielding, and avoid chromatograph purification and led environmentally benign total synthesis of focused oxadiazole library. All the synthesized compounds were isolated in good yield and characterized by 1H NMR, 13C NMR, and elemental analyses. The title compounds represent a novel class of biologically active heterocycles.

scholarly journals Highly efficient synthesis of [60]fullerene oxides by plasma jet

2017 ◽  
Vol 4 (9) ◽  
pp. 170658 ◽  
Author(s):  
Sheng-Peng Jiang ◽  
Shengxia Duan ◽  
Kai-Qing Liu ◽  
Xiao-Yu Yang ◽  
Cheng Cheng ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
Theoretical Calculations ◽  
Chemical Shifts ◽  
Plasma Jet ◽  
Nonequilibrium Plasma ◽  
Efficient Synthesis ◽  
Structural Assignment ◽  
High Yields ◽  
First Time ◽  
C Nmr

Atmospheric pressure nonequilibrium plasma jet has been applied to the synthesis of [60]fullerene oxides (C 60 O n ) for the first time. C 60 O and C 60 O 2 were produced and isolated in high yields up to 44% and 21%, respectively. The structural assignment of C 60 O was confirmed by comparison with the reported spectroscopic data. Theoretical calculations of 13 C NMR chemical shifts for eight isomers of C 60 O 2 were performed and compared with the experimental data to assign the most possible structure for the obtained C 60 O 2 dominantly as an e isomer.

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