Methylation of Acridin-9-ylthioureas. Structure, Fluorescence and Biological Properties of Products

2004 ◽  
Vol 69 (4) ◽  
pp. 833-849 ◽  
Author(s):  
Juraj Bernát ◽  
Eva Balentová ◽  
Pavol Kristian ◽  
Ján Imrich ◽  
Erik Sedlák ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Biological Activity ◽  
Ab Initio ◽  
Quantum Chemical ◽  
Biological Properties ◽  
Reaction Conditions ◽  
Alkyl Aryl ◽  
Nmr Techniques ◽  
Primary Amino ◽  
Secondary Amino

The structure, fluorescence, biological properties and S(N)-methylation reactions of ten 1,1-alkyl/aryl-disubstituted 3-(acridin-9-yl)thioureas 4 have been studied. Various reaction conditions allowed to obtain corresponding S-methyl 5 and S,N-dimethyl derivatives 6 in good yields. Structure and stereochemistry of the synthesized products are demonstrated by ab initio quantum chemical calculations and NMR techniques including PDQF-COSY, selective INEPT and NOE-difference experiments. Remarkable upfield 13C shifts of resonance signals of carbons C-4a, C-10a adjacent to acridine N-10 are characteristic of hydroiodides in contrast to free bases. Z configuration in isothioureas 7 with secondary amino rest in relation to E configuration of isothioureas with primary amino rest is discussed. Of the obtained products, some isothiourea salts 6 exhibit more than 2 orders of magnitude higher intensity of fluorescence, using 9-isothiocyanatoacridine as a standard. The obtained isothiourea hydroiodides 5 and dimethylisothiourea iodides 6 show remarkable biological activity against Mycobacterium tuberculosis.

Evaluation of Chemotherapeutic Activity of the Selected Bases’ Analogues of Nucleic Acids Supported by ab initio Various Quantum Chemical Calculations

2020 ◽  
Vol 16 (2) ◽  
pp. 93-103 ◽  
Author(s):  
Piotr Kawczak ◽  
Leszek Bober ◽  
Tomasz Bączek
Keyword(s):  
Biological Activity ◽  
Nucleic Acids ◽  
Ab Initio ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Structural Parameters ◽  
Principal Component ◽  
Polarizable Continuum Model ◽  
Activity Data ◽  
Qsar Models

Background: Pharmacological and physicochemical classification of bases’ selected analogues of nucleic acids is proposed in the study. Objective: Structural parameters received by the PCM (Polarizable Continuum Model) with several types of calculation methods for the structures in vacuo and in the aquatic environment together with the huge set of extra molecular descriptors obtained by the professional software and literature values of biological activity were used to search the relationships. Methods: Principal Component Analysis (PCA) together with Factor Analysis (FA) and Multiple Linear Regressions (MLR) as the types of the chemometric approach based on semi-empirical ab initio molecular modeling studies were performed. Results: The equations with statistically significant descriptors were proposed to demonstrate both the common and differentiating characteristics of the bases' analogues of nucleic acids based on the quantum chemical calculations and biological activity data. Conclusion: The obtained QSAR models can be used for predicting and explaining the activity of studied molecules.

Synthesis of New α-Amino Phosphonates Containing 3-Amino-4(3H) Quinazolinone Moiety as Anticancer and Antimicrobial Agents: DFT, NBO, and Vibrational Studies

2018 ◽  
Vol 15 (2) ◽  
pp. 286-296 ◽  
Author(s):  
Mohamed K. Awad ◽  
Mahmoud F. Abdel-Aal ◽  
Faten M. Atlam ◽  
Hend A. Hekal
Keyword(s):  
Biological Activity ◽  
Cell Line ◽  
Quantum Chemical ◽  
Density Functional ◽  
Carcinoma Cell ◽  
Liver Carcinoma ◽  
Anticancer Activities ◽  
Functional Theory ◽  
Ft Ir ◽  
Good Agreement

Aim and Objective: Synthesis of new .-aminophosphonates containing quinazoline moiety through Kabachnik-Fields reaction in the presence of copper triflate catalyst [32], followed by studying their antimicrobial activities and in vitro anticancer activities against liver carcinoma cell line (HepG2) with the hope that new anticancer agents could be developed. Also, the quantum chemical calculations are performed using density functional theory (DFT) to study the effect of the changes of molecular and electronic structures on the biological activity of the investigated compounds. Materials and Method: The structures of the synthesized compounds are confirmed by FT-IR, 1H NMR, 13C NMR, 31P NMR and MS spectral data. The synthesized compounds show significant antimicrobial and also remarkable cytotoxicity anticancer activities against liver carcinoma cell line (HepG2). Density functional theory (DFT) was performed to study the effect of the molecular and electronic structure changes on the biological activity. Results: It was found that the electronic structure of the substituents affects on the reaction yield. The electron withdrawing substituent, NO2 group 3b, on the aromatic aldehydes gave a good yield more than the electron donating substituent, OH group 3c. The electron deficient on the carbon atom of the aldehydic group may increase the interaction of the Lewis acid (Cu(OTf)2) and the Lewis base (imine nitrogen), and accordingly, facilitate the formation of imine easily, which is attacked by the nucleophilic phosphite species to give the α- aminophosphonates. Conclusion: The newly synthesized compounds exhibit a remarkable inhibition of the growth of Grampositive, Gram-negative bacteria and fungi at low concentrations. The cytotoxicity of the synthesized compounds showed a significant cytotoxicity against the liver cancer cell line (HepG 2). Also, it was shown from the quantum chemical calculations that the electron-withdrawing substituent increases the biological activity of the α-aminophosphonates more than the electron donating group which was in a good agreement with the experimental results. Also, a good agreement between the experimental FT-IR and the calculated one was found.

Quantum chemical prediction of 2H-pyran vibration spectrum

1990 ◽  
Vol 55 (1) ◽  
pp. 10-20 ◽  
Author(s):  
Stanislav Böhm ◽  
Josef Kuthan
Keyword(s):  
Vibrational Spectrum ◽  
Ab Initio ◽  
Quantum Chemical ◽  
Vibration Spectrum ◽  
Equilibrium Geometry ◽  
Heterocyclic Molecule ◽  
Vibrational Transitions ◽  
Correlation Corrections

Ab initio MO optimalization of the 2H-pyran molecule leads to a defined equilibrium geometry of this so far not identified heterocyclic molecule and to a physical justification of its existence. More advanced nonempirical wavefunctions and temperature corrections indicate that heterocyclic molecule I is energetically less stable than non-cyclic isomers II and III. Wavenumbers of fundamental vibrational transitions of heterocycle I and also known (2E)-2,4-pentadienal (IIIb were calculated using 3-21 G wavefunctions. The vibrational spectrum of compound I is predicted on the basis of correlation corrections.

Biological Function and Chemistry of Endothelin. A Review

1999 ◽  
Vol 64 (8) ◽  
pp. 1211-1252 ◽  
Author(s):  
Jan Hlaváček ◽  
Renáta Marcová
Keyword(s):  
Biological Activity ◽  
Amino Acid ◽  
Biological Function ◽  
Biological Properties ◽  
Structural Basis ◽  
Amino Acid Residues ◽  
Snake Venoms ◽  
Vasoactive Peptides ◽  
Physico Chemical ◽  
Endothelin A

The first part of this review deals with the biosynthesis and a biological function of strongly vasoactive peptides named endothelins (ETs) including vasoactive intestinal contractor. Where it was useful, snake venoms sarafotoxins which are structural endothelin derivatives, were also mentioned. In the second part, an attention is paid to structural basis of the ETs biological activity, with respect to alterations of amino acid residues in the parent peptides modifying the conformation and consequently the physico-chemical and biological properties in corresponding ETs analogs. Special attention is focussed on the area of ETs receptors and their interaction with peptide and non peptide agonists and antagonists, important in designing selective inhibitors of ETs receptors potentially applicable as drugs in a medicine. A review with 182 references.

scholarly journals Prebiotic Route to Thymine from Formamide—A Combined Experimental–Theoretical Study

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2248
Author(s):  
Lukáš Petera ◽  
Klaudia Mrazikova ◽  
Lukas Nejdl ◽  
Kristyna Zemankova ◽  
Marketa Vaculovicova ◽  
...  
Keyword(s):  
Formic Acid ◽  
Quantum Chemical ◽  
Prebiotic Chemistry ◽  
Theoretical Study ◽  
Reaction Pathway ◽  
Hydrolysis Product ◽  
Current Paper ◽  
Reaction Conditions ◽  
Chemical Modeling ◽  
Chemistry Research

Synthesis of RNA nucleobases from formamide is one of the recurring topics of prebiotic chemistry research. Earlier reports suggest that thymine, the substitute for uracil in DNA, may also be synthesized from formamide in the presence of catalysts enabling conversion of formamide to formaldehyde. In the current paper, we show that to a lesser extent conversion of uracil to thymine may occur even in the absence of catalysts. This is enabled by the presence of formic acid in the reaction mixture that forms as the hydrolysis product of formamide. Under the reaction conditions of our study, the disproportionation of formic acid may produce formaldehyde that hydroxymethylates uracil in the first step of the conversion process. The experiments are supplemented by quantum chemical modeling of the reaction pathway, supporting the plausibility of the mechanism suggested by Saladino and coworkers.

Theoretical analysis of means of preventing Si–C bond cleavage during polycondensation of organosilanes to organosilicas

2021 ◽  
Author(s):  
Soichi Shirai ◽  
Shinji Inagaki
Keyword(s):  
Theoretical Analysis ◽  
Ab Initio ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Bond Cleavage ◽  
Model Compounds ◽  
Analysis Of Means

Practical strategies for suppressing Si–C cleavage during the polycondensation of organosilanes were presented based on ab initio quantum chemical calculations of model compounds.

Ab initio quantum-chemical calculations of the energies and structures of 1,2-acetylenedithiol isomers

2009 ◽  
Vol 50 (2) ◽  
pp. 195-200 ◽  
Author(s):  
Yu. V. Frolov ◽  
A. V. Vashchenko ◽  
A. G. Mal’kina ◽  
B. A. Trofimov
Keyword(s):  
Ab Initio ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical
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