Margita Lácová

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

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.

Reactions of 3-Formylchromone with Active Methylene and Methyl Compounds and Some Subsequent Reactions of the Resulting Condensation Products.

This review presents a survey of the condensations of 3-formylchromone with various active methylene and methyl compounds, e.g. malonic or barbituric acid derivatives, five-membered heterocycles, etc. The utilisation of the condensation products for the synthesis of different heterocyclic systems, which is based on the ability of the γ-pyrone ring to be opened by the nucleophilic attack is also reviewed. Finally, the applications of microwave irradiation as an unconventional method of reaction activation in the synthesis of condensation products is described and the biological activity of some chromone derivatives is noted.

Effect of Microwave Irradiation on the Condensation of 6-Substituted 3-Formylchromones with Some Five-membered Heterocyclic Compounds

Central Laboratories, Faculty of Chemical Technology, Slovak University of Technology, SK-812 37Bratislava, Slovak RepublicReceived: 14 November 1999 / Accepted: 31 December 1999 / Published: 19 February 2000Abstract: Different types of 3-substituted 4H-4-oxobenzopyrans were prepared by micro-wave irradiation as well as by a classical method. The beneficial effect of microwave irra-diation on the aldol condensation of 3-formylchromones with 2-imino-1-methyl-imidazolidine-4-one (creatinine), 2-thioxoimidazolidine-4-one (thiohydantoin) and 2-ethyl-2-thioxothiazolidin-4-one (3-ethylrhodanine) in different reaction media is described. Ourresults show that the effect of microwave irradiation on the reactions studied was a shorten-ing of the reaction times and a smooth increase in the yields. The subsequent reactions ofthe product with some nucleophiles are discussed. The structure of the products was provenby elemental analysis, IR and NMR spectra.Keywords: Creatinine, thiohydantoin, rhodanine, carbamoic acids, guanidine derivatives,Diels - Alder reaction, IR,

Reaction of 3-formylchromones with aromatic amino carboxylic acids

Abstract 2-Alkoxy-3-(arylaminomethylene)chroman-4-ones and 3-(aryliminomethyl)chromones were prepared by acid catalyzed reaction of 3-formylchromones with aromatic amino carboxylic acids in alcoholic reaction media. The results of the kinetic study have confirmed that 3-(aryliminomethyl)chromones are formed from 2-alkoxy-3-(arylaminomethylene)chroman-4-ones. The dependence of the reaction rate on reactant structure, the reaction media and the concentration of catalyst has been studied. In contrast to the alcoholic media reaction, the same reaction in dry aprotic reaction media yielded only 2-hydroxy-3-(arylaminomethylene)chroman-4-ones. No 3-(aryliminomethyl)chromones were isolated in that case.

MICROWAVES ASSISTED GABRIEL SYNTHESIS OF PHTHALIDES

Abstract Cesium acetate was found to be the best catalyst for the synthesis of 3-benzylidenephthalide from phthalic anhydride and phenylacetic acid. Reasonable to good yields of different 3-arylmethylenephthalides were isolated from the microwave Gabriel synthesis, even when phenylthio- and 2-(3-)thienyl- acetic acids were used as the starting material.

Synthesis and Reactions of New 4-Oxo-4H-benzopyran-3-carboxaldehydes Containing Hydroxy Groups or 2-Oxopyran Cycles

The synthesis of eight hydroxy- and 2-oxopyranochromone-3-carboxaldehydes 3, 5 and their reactions with 2-hydroxyaniline, 2,4-dinitrophenylhydrazine and 2-benzothiazolylhydrazine were investigated. Products were confirmed by IR, NMR spectral and elemental analysis data. The semi-empirical AM1 quantum-chemical method has been used to study optimal geometries and heats of formation of synthesized 3-formylchromones.

Infrared spectra and theoretical study of methyl, formyl and acetyl derivatives of chromones

SummaryThe C=O stretching frequencies of substituted 2-methylchromones (3a–3j), 2-formylchromones (4a–4j), 3-formylchromones (5a–5j) and 3-acetyl-2-methylchromones (6a–6i) were measured in CCl4 and CHCl3 and correlated with σ+ substituent constants. Using the results of the infrared spectral investigation and the theoretical calculations by the semiempirical AM1 method, the conformation and the transmission of electronic effects in compounds4–6 were studied. For the 2-substituted chromone system the transmission factory γ according to the definition of Charton was determined. The preparation of some new 2-methylchromones (3e–3j) and 3-(2,2-diformyl-chlorovinyl)-6-methylchromone (7) is also described.ZusammenfassungEs wurden die C=O-Streckschwingungsfrequenzen von substituierten 2-Methyl-chromonen (3a–3j), 2-Formylchromonen (4a–4j), 3-Formyl-chromonen (5a–5j) und 3-Acetyl-2-methylchromonen (6a–6j) in CCl4 und CHCl3 gemessen und mit den σ+-Substituenteknonstanten korreliert. Unter Verwendung der IR-Resultate und theoretischer Behandlung mit Hilfe semiempirischer AM1-Rechnungen wurden die Konformationen und die Transmission elektronischer Effekte in den untersuchten Verbindungen4–6 untersucht. Für die 2-substituierten Chromon-Systeme wurde der Transmissionsfaktor γ entsprechend der Definition von Charton bestimmt. Die Herstellung einiger neuer 2-Methylchromone (3e–3j) und 3(2,2-Diformyl-1-chlorvinyl)-6 methylchromon (7) wird ebenfalls beschrieben.

3-Formylchromones IV. The Rearrangement of 3-Formylchromone Enamines as a Simple, Facile Route to Novel Pyrazolo[3,4-b]pyridines and the Synthetic Utility of the Latter

One-pot and facile preparations of 6-(2-hydroxy-5-R-benzoyl)-4-methyl-2-R1- pyrazolo[3,4-b]pyridines 4a-o are described, using the reaction of 3-formyl chromones 1 with 5-amino-1-R1-pyrazoles 2. An enamine-intermediate 2-ethyloxy-6-R-3-(3-methyl-1- phenylpyrazol-5-ylaminomethylene)chroman-4-one 3 was isolated at lower temperatures. Acyloxy-derivatives 5 of compounds 4 were obtained by acylation with acid chlorides or acid anhydrides. Coumarins 6 substituted at the 3- and 4-positions were prepared from the pyrazolo[3,4-b]pyridines 4 by condensation reactions and hydrazones 7 were formed from their reaction with 2,4-dinitrophenyl hydrazine. Reactions under microwave irradiation proceeded significantly faster and with high yields.

Reactions of substituted furo[3,2-b]pyrrole-5-carboxhydrazides and their biological activity

The reactions of substituted furo[3,2-b]pyrrole-5-carboxhydrazides 1 with 5-arylfuran-2-carboxaldehydes 2, 4,5-disubstituted furan-2-carboxaldehydes 3 and thiophene-2-carboxaldehyde 4 has been studied. The advantage of microwave irradiation on some of these reactions was reflected in the reduced reaction time and increased yields. Reactions of 1 with 4-substituted 1,3-oxazol-5(4H)-ones 11 led to diacylhydrazines 13 or to imidazole derivatives 14 depending on the temperature. 1,2,4-Triazole-3-thione 17 was synthesized by two-step reaction of 1 with phenylisothiocyanate and subsequent base-catalyzed cyclization of thiosemicarbazide 16. The effects of hydrazones 5–10 on inhibition of photosynthetic electron transport in spinach chloroplasts and chlorophyll content in the antialgal suspensions of Chlorella vulgaris were investigated.

Evaluation of Effect of Microwave Irradiation on Syntheses and Reactions of Some New 3-Acyl-methylchromones

The 3-Acyl-2-R-methylchromones (R = H, ArO, C6H4(CO)2N) were prepared in good yields by different methods from 2-hydroxyaroylacetone derivatives. Some subsequent reactions of these compounds with hydroxylamine and 3-formylchromones are described. The effect of microwave irradation on some condensation reactions was studied.