: The unpolarized absorption and circular dichroism spectra of the fundamental vibrational transitions of the chiral molecule, 4-methyl-2-oxetanone, are calculated ab initio. Harmonic force fields are obtained using Density Functional Theory (DFT), MP2, and SCF methodologies and a 5S4P2D/3S2P (TZ2P) basis set. DFT calculations use the Local Spin Density Approximation (LSDA), BLYP, and Becke3LYP (B3LYP) density functionals. Mid-IR spectra predicted using LSDA, BLYP, and B3LYP force fields are of significantly different quality, the B3LYP force field yielding spectra in clearly superior, and overall excellent, agreement with experiment. The MP2 force field yields spectra in slightly worse agreement with experiment than the B3LYP force field. The SCF force field yields spectra in poor agreement with experiment.The basis set dependence of B3LYP force fields is also explored: the 6-31G* and TZ2P basis sets give very similar results while the 3-21G basis set yields spectra in substantially worse agreements with experiment. jg

Ab initio calculation of vibrational absorption and circular dichroism spectra using density functional force fields

This work was supported by the Foundation for Science and Technology (FCT), Portugal (projects PTDC/QUI-QUI/113687/2009 and PEst-C/QUI/UI0081/2013). A.G. (SFRH/BD/43531/2008) and M.J.M. (SFRH/BD/61262/2009) thank FCT for grants.

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Chromone: A Valid Scaffold in Medicinal Chemistry

Chromones as a privileged scaffold in drug discovery: a review.

Synthesis of novel 2-mercapto benzothiazole and 1,2,3-triazole based bis-heterocycles: their anti-inflammatory and anti-nociceptive activities.

Heterocycles bearing nitrogen, sulphur and thiazole moieties constitute the core structure of a number of biologically interesting compounds. Benzothiazole, a group of xenobiotic compounds containing a benzene ring fused with a thiazole ring, are used worldwide for a variety of therapeutic applications. Benzothiazole and their heterocyclic derivatives represent an important class of compounds possessing a wide spectrum of biological activities. The myriad spectrum of medicinal properties associated with benzothiazole related drugs has encouraged the medicinal chemists to synthesize a large number of novel therapeutic agents. Several analogues containing benzothiazole ring system exhibit significant antitumour, antimicrobial, antidiabetic, anti-inflammatory, anticonvulsant, antiviral, antioxidant, antitubercular, antimalarial, antiasthmatic, anthelmintic, photosensitizing, diuretic, analgesic and other activities. This article is an attempt to present the research work reported in recent scientific literat...

https://www.tandfonline.com/doi/pdf/10.3109/14756366.2012.720572

Medicinal significance of benzothiazole scaffold: an insight view

The synthesis of the biologically active novel systems derived from reaction of 3-formylchromones with three types of amino derivatives, 6-R2-2-aminobenzothiazoles, 6-amino-2-R3-thiobenzothiazoles and hydrazide derivatives (derived from cyanoacetic, isonicotine, salicylic and gallic acids) was carried out. The structures of the prepared compounds have been proved by elemental analysis, 1H NMR and IR spectra. Antimicrobial activity was studied against the following microorganisms — bacteria G+ (Staphylococcus aureus 29 58 , Bacillus subtilis 18 66 ), G− (Escherichia coli 326 71 , Pseudomonas aeruginosa); yeasts; Candida albicans, Saccharomyces cerevisiae; moulds; Microsporum gypseum, Aspergillus niger, Scopulariopsis brevicaulis; and against typical and atypical mycobacteria: Mycobacterium tuberculosis (H37Rv), Mycobacterium kansasii (PFG 8), Mycobacterium avium (My 80 72 ), Mycobacterium fortuitum (1021). The hereditary bleaching effect on the plastid system of Euglena gracilis, a unique phenomenon of the biological activity of chromone derivatives, is reported. The bleaching test on E. gracilis is used for detecting extranuclear mutations.

Synthesis, antimicrobial activity and bleaching effect of some reaction products of 4-oxo-4H-benzopyran-3-carboxaldehydes with aminobenzothiazoles and hydrazides

Donor–π-acceptor benzothiazole-derived dyes with an extended heteroaryl-containing conjugated system: synthesis, DFT study and antimicrobial activity

Substitution with NO2, Cl, Br and I into position 6 of 2-benzthiazoIthiol derivatives increased their antimicrobial efficiency while the SH group is preserved. This increase affected both G+ and G-bacteria, mycobacteria and some fungi The degree of efficiency of the benzthiazol derivatives is also influenced by the substituent in position 2.

Antimicrobial effects of some benzthiazol derivatives

The hereditary bleaching test on Euglena gracilis was used for detecting extranuclear mutations. The highest bleaching activity (induction of the chloroplast-free mutants) was shown by the 6- R -3-formylchromones. On the other hand, bleaching-inactive 6- R -3-formylchromone acylhydrazones (derived from gallic and salicylic acids), added at sufficient concentrations in the case of chloroplast mutagenesis in E. gracilis , act as a potent antimutagen. This effect appeared to be a unique feature of chromone derivatives, but was dependent on the type of mutagen. These substances were very effective against the bleaching activity of acridine orange, and were less effective against N -methyl- N ′-nitro- N -nitrosoguanidine. The genotoxic effects of these mutagens was reduced, especially during the first stages of induction of this specific cytoplasmic mutation. The experimental study of mutagenicity and antimutagenicty of 3-formylchromone hydrazones was reinforced by data obtained by the semi-empirical AM1 method and lipophilicity values.

Activity of some 3-formylchromone derivatives on the induction of chloroplast-free mutants in Euglena gracilis

Eleven new 2-styrylbenzothiazole-N-oxides have been prepared by aldol – type condensation reactions between 2-methylbenzothiazole–N-oxide and para-substituted benzaldehydes. Compounds with cyclic amino substituents showed typical push-pull molecule properties. Four compounds were tested against various bacterial strains as well as the protozoan Euglena gracilis as model microorganisms. Unlike previously prepared analogous benzothiazolium salts, only weak activity was recorded.

P. Foltinova

Papers

Synthesis, antimicrobial activity and bleaching effect of some reaction products of 4-oxo-4H-benzopyran-3-carboxaldehydes with aminobenzothiazoles and hydrazides

Donor–π-acceptor benzothiazole-derived dyes with an extended heteroaryl-containing conjugated system: synthesis, DFT study and antimicrobial activity

Antimicrobial effects of some benzthiazol derivatives

Activity of some 3-formylchromone derivatives on the induction of chloroplast-free mutants in Euglena gracilis

New conjugated benzothiazole-N-oxides: synthesis and biological activity.