scholarly journals Pyridinoacridine alkaloids of marine origin: NMR and MS spectral data, synthesis, biosynthesis and biological activity

2015 ◽  
Vol 11 ◽  
pp. 1667-1699 ◽  
Author(s):  
Louis P Sandjo ◽  
Victor Kuete ◽  
Maique W Biavatti
Keyword(s):  
Chemical Shift ◽  
Mass Spectra ◽  
Marine Sponges ◽  
Biomimetic Synthesis ◽  
Marine Alkaloids ◽  
Hydrogen Atoms ◽  
Data Synthesis ◽  
Synthesis Routes ◽  
Shift Assignment ◽  
C Nmr

This review focuses on pyridoacridine-related metabolites as one biologically interesting group of alkaloids identified from marine sources. They are produced by marine sponges, ascidians and tunicates, and they are structurally comprised of four to eight fused rings including heterocycles. Acridine, acridone, dihydroacridine, and quinolone cores are features regularly found in these alkaloid skeletons. The lack of hydrogen atoms next to quaternary carbon atoms for two or three rings makes the chemical shift assignment a difficult task. In this regard, one of the aims of this review is the compilation of previously reported, pyridoacridine 13C NMR data. Observations have been made on the delocalization of electrons and the presence of some functional groups that lead to changes in the chemical shift of some carbon resonances. The lack of mass spectra information for these alkaloids due to the compactness of their structures is further discussed. Moreover, the biosynthetic pathways of some of these metabolites have been shown since they could inspire biomimetic synthesis. The synthesis routes used to prepare members of these marine alkaloids (as well as their analogues), which are synthesized for biological purposes are also discussed. Pyridoacridines were found to have a large spectrum of bioactivity and this review highlights and compares the pharmacophores that are responsible for the observed bioactivity.

Synthesis of 2-amino-5,7-dimethyl-4-oxopyrido[3,4-e]-1,3-thiazines

1983 ◽  
Vol 48 (12) ◽  
pp. 3426-3432 ◽  
Author(s):  
Dušan Koščík ◽  
Pavol Kristian ◽  
Ondrej Forgáč
Keyword(s):  
Spectral Data ◽  
Chlorine Atom ◽  
Mass Spectra ◽  
High Reactivity ◽  
Secondary Amines ◽  
Dimroth Rearrangement ◽  
H Nmr ◽  
New Synthesis ◽  
C Nmr

New synthesis of pyrido[3,4-e]-1,3-thiazines consisting in reaction of 2,6-dimethyl-4-chloronicotinoyl isothiocyanate with primary or secondary amines, or with benzaldehyde phenylhydrazone, is described. High reactivity of the chlorine atom does not allow isolation of the corresponding thioureas, arising as intermediates, except in the case of the benzylamino derivative. Structure of the products was unequivocally confirmed by their spectral data (IR, UV, 1H NMR, 13C NMR and mass spectra). The synthesized derivatives do not undergo the Dimroth rearrangement.

Oxynemorensine, an alkaloid from Senecio nemorensis L., var. subdecurrens GRISEB

1980 ◽  
Vol 45 (2) ◽  
pp. 548-558 ◽  
Author(s):  
Antonín Klásek ◽  
Petr Sedmera ◽  
Jindřich Vokoun ◽  
Anna Boeva ◽  
Svatava Dvoráčková ◽  
...  
Keyword(s):  
Unsaturated Acid ◽  
Mass Spectra ◽  
H Nmr ◽  
C Nmr

From S. nemorensis L., var. subdecurrens GRISEB. there were isolated the previously obtained alkaloids nemorensine (I), retroisosenine (II), bulgarsenine (III) and, in addition, the alkaloid oxynemorensine which was assigned the structure VIII on the basis of the interpretation of the 1H-NMR, 13C-NMR, mass spectra, and on that of the identification of the products of hydrolysis and reduction. Furthermore, the isolation of the cis-nemorensic acid (V) as well as that of the unsaturated acid IV, and the transformation of bulgarsenine (III) to nemorensine (I) were described.

scholarly journals 1H, 13C and 15N assignment of stem-loop SL1 from the 5'-UTR of SARS-CoV-2

2021 ◽  
Author(s):  
Christian Richter ◽  
Katharina F. Hohmann ◽  
Sabrina Toews ◽  
Daniel Mathieu ◽  
Nadide Altincekic ◽  
...  
Keyword(s):  
Life Cycle ◽  
Chemical Shift ◽  
Base Pair ◽  
Chemical Shift Assignment ◽  
Potential Functions ◽  
Regulatory Rna ◽  
Structural Element ◽  
Stem Loop ◽  
Internal Loop ◽  
Shift Assignment

AbstractThe stem-loop (SL1) is the 5'-terminal structural element within the single-stranded SARS-CoV-2 RNA genome. It is formed by nucleotides 7–33 and consists of two short helical segments interrupted by an asymmetric internal loop. This architecture is conserved among Betacoronaviruses. SL1 is present in genomic SARS-CoV-2 RNA as well as in all subgenomic mRNA species produced by the virus during replication, thus representing a ubiquitous cis-regulatory RNA with potential functions at all stages of the viral life cycle. We present here the 1H, 13C and 15N chemical shift assignment of the 29 nucleotides-RNA construct 5_SL1, which denotes the native 27mer SL1 stabilized by an additional terminal G-C base-pair.

NMR studies of tandem WW domains of Nedd4 in complex with a PY motif-containing region of the epithelial sodium channel

1998 ◽  
Vol 76 (2-3) ◽  
pp. 341-350 ◽  
Author(s):  
Voula Kanelis ◽  
Neil A Farrow ◽  
Lewis E Kay ◽  
Daniela Rotin ◽  
Julie D Forman-Kay
Keyword(s):  
Chemical Shift ◽  
Sodium Channel ◽  
Chemical Shifts ◽  
Epithelial Sodium Channel ◽  
Chemical Shift Assignment ◽  
Nmr Studies ◽  
Ww Domains ◽  
Ww Ii ◽  
Py Motif ◽  
Shift Assignment

Nedd4 (neuronal precursor cell-expressed developmentally down-regulated 4) is a ubiquitin-protein ligase containing multiple WW domains. We have previously demonstrated the association between the WW domains of Nedd4 and PPxY (PY) motifs of the epithelial sodium channel (ENaC). In this paper, we report the assignment of backbone 1Hα, 1HN, 15N, 13C', 13Cα, and aliphatic 13C resonances of a fragment of rat Nedd4 (rNedd4) containing the two C-terminal WW domains, WW(II+III), complexed to a PY motif-containing peptide derived from the β subunit of rat ENaC, the βP2 peptide. The secondary structures of these two WW domains, determined from chemical shifts of 13Cα and 13Cβ resonances, are virtually identical to those of the WW domains of the Yes-associated protein YAP65 and the peptidyl-prolyl isomerase Pin1. Triple resonance experiments that detect the 1Hα chemical shift were necessary to complete the chemical shift assignment, owing to the large number of proline residues in this fragment of rNedd4. A new experiment, which correlates sequential residues via their 15N nuclei and also detects 1Hα chemical shifts, is introduced and its utility for the chemical shift assignment of sequential proline residues is discussed. Data collected on the WW(II+III)-βP2 complex indicate that these WW domains have different affinities for the βP2 peptide.Key words: WW domain, PY motif, Nedd4, ENaC, NMR.

Determination of chemical shifts in 6-condensed syringylic lignin model compounds

Holzforschung ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Lucas Lagerquist ◽  
Jani Rahkila ◽  
Patrik Eklund
Keyword(s):  
Chemical Shift ◽  
Methoxy Group ◽  
Chemical Shifts ◽  
Model Compounds ◽  
Correlation Peak ◽  
Lignin Model Compounds ◽  
Benzylic Alcohols ◽  
Lignin Model ◽  
C Nmr

Abstract A small library of 6-substituted syringyl model compounds with aliphatic, carboxylic, phenylic, benzylic alcohols and brominated substituents were prepared. The influence of the substituents on the chemical shifts of the compounds was analyzed. All of model compounds showed a characteristic increase in the 13C NMR chemical shift of the methoxy group vicinal to the substitution. This 13C NMR peak and its corresponding correlation peak in HSQC could potentially be used to identify 6-condensation in syringylic lignin samples.

Mass spectra of some deuterated ethanes. II. An empirical method of calculation of the spectra

1968 ◽  
Vol 46 (10) ◽  
pp. 1741-1746 ◽  
Author(s):  
Y. Amenomiya. ◽  
R. F. Pottie
Keyword(s):  
Mass Spectra ◽  
Reasonable Agreement ◽  
Empirical Method ◽  
Bond Rupture ◽  
Hydrogen Atoms ◽  
Method Of Calculation ◽  
Weighting Factors ◽  
Fragment Ions ◽  
Calculated Mass ◽  
Doubly Charged

Relative intensities of the C2 fragment ions in deuterated (d1–d5) ethanes have been calculated on a statistical basis from the mass spectrum of C2H6 and have been compared with experimental mass spectra previously reported in Part I. For these calculations we have introduced a correction for the relative probabilities of loss of two hydrogen atoms in addition to weighting factors for the loss of H and D atoms. The isotopic weighting factors have been expressed in terms of power series. By this means satisfactory agreement was obtained between the calculated and experimental mass spectra.This treatment also made it possible to calculate the intensities of doubly charged C2 fragments that appear in the C1 mass spectra. We then estimated the degree of reshuffling of hydrogen atoms prior to C—C bond rupture and obtained calculated mass spectra that were in reasonable agreement with the experimental data for the C1 region of the mass spectrum.Experimental mass spectra have been newly obtained for 1,1-d2 ethane and 1,1,1,2-d4 ethane and are included here for completeness.

13C NMR CHEMICAL SHIFT CALCULATION FOR THE 1, 1'-DISUBSTITUTED FERROCENE COMPOUNDS

1986 ◽  
Vol 2 (01) ◽  
pp. 73-76
Author(s):  
Li Cun ◽  
◽  
Wu Weixiong ◽  
Pen Xin ◽  
Chao Qirong ◽  
...  
Keyword(s):  
Chemical Shift ◽  
Nmr Chemical Shift ◽  
Ferrocene Compounds ◽  
Shift Calculation ◽  
C Nmr

scholarly journals Some Decomposition Routes in the Mass Spectra of Aromatic Carboxylic Acids

1965 ◽  
Vol 20 (7) ◽  
pp. 883-887 ◽  
Author(s):  
J. H. Beynon ◽  
B. E. Job ◽  
A. E. Williams
Keyword(s):  
Carboxylic Acid ◽  
Benzoic Acid ◽  
Terephthalic Acid ◽  
Phthalic Acid ◽  
Mass Spectra ◽  
Deuterium Atom ◽  
Acid Group ◽  
Isophthalic Acid ◽  
Carboxylic Acid Group ◽  
Hydrogen Atoms

The mass spectra of benzoic acid, phthalic acid, isophthalic acid and terephthalic acid, together with the analogues deuterated on the carboxylic acid group have been studied. Exchange of the deuterium atom with hydrogen atoms on the positions ortho to a carboxylic acid group on the aromatic ring has been studied using meta-stable peaks.

scholarly journals Synthesis, characterization, and antimicrobial activities of novel double-armed benzo-15-crown-5 and their sodium and potassium complexes

2020 ◽  
pp. 174751982093226
Author(s):  
Öznur Şener Cemaloğlu ◽  
Hatice Ogutcu ◽  
Zeliha Hayvalı
Keyword(s):  
Schiff Base ◽  
Crown Ether ◽  
Mass Spectra ◽  
Sodium Perchlorate ◽  
Antimicrobial Activities ◽  
Pathogenic Microorganisms ◽  
Inhibitory Effects ◽  
Antibacterial Effects ◽  
Sodium And Potassium ◽  
C Nmr

New aldehyde- and halogen- (Cl, Br, I) substituted double-armed benzo-15-crown-5 derivatives are synthesized by the reactions of 4′,5′-bis(bromomethyl)benzo-15-crown-5 with 5-chlorosalicylaldehyde, 5-bromosalicylaldehyde, or 5-iodosalicylaldehyde. The sodium and potassium complexes are obtained by reaction of crown ether with sodium perchlorate and potassium iodide, respectively. Novel Schiff base compounds containing three groups of benzo-15-crown-5 are obtained from the condensation of aldehydes with 4′-aminobenzo-15-crown-5. The structures of all compounds are elucidated by elemental analysis, 1H, 13C NMR, IR, and mass spectra. The antifungal and antibacterial effects of the synthesized ligands are evaluated against pathogenic microorganisms and show varying degrees of inhibitory effects against the growth of different pathogenic strains. Graphical abstract

scholarly journals A New Isocoumarin from Cajanus cajan (Fabaceae)

2014 ◽  
Vol 9 (4) ◽  
pp. 1934578X1400900 ◽  
Author(s):  
Virginia F. Rodrigues ◽  
Rodrigo R. Oliveira ◽  
Maria Raquel G. Vega
Keyword(s):  
Spectral Data ◽  
Cajanus Cajan ◽  
Mass Spectra ◽  
2D Nmr ◽  
C Nmr

A new isocoumarin, 3-phenyl-8-hydroxy-6-methoxy-5-γ, γ-dimethylallyl-isocoumarin, named cajavilmina (1) and eight known compounds: α-amirenone (2), β-amirenone (3), lupenone (4), 5-hydroxy-7-methoxydihydroflavone (5), longistilin C (6), 3-hydroxy-5-methoxystilbene (7), β-sitosterol (8) and stigmasterol (9) were identified in a dichloromethane fraction from Cajanus cajan leaves. Structures were elucidated by analysis of spectral data, mainly those afforded by 1H, NOEDIFF and 13C NMR (1D and 2D NMR HMQC, HMBC and COSY) and mass spectra.

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