Microwave assisted organic synthesis-a review

Drugs for treating tuberculosis (TB) have been available for over half a century, and yet the incidence of disease worldwide continues to rise year by year. In 2002, the last year for which statistics are available, it is estimated that 24,000 people developed active disease and close to 5,000

New Small-Molecule Synthetic Antimycobacterials

Benzotriazole: An overview on its versatile biological behavior

Chemical probes of UDP-galactopyranose mutase

The impressive pharmacological properties shown by a number of coumarins have led to extraordinarily large emphasis being placed on the design of more efficient and greener synthetic procedures to produce them. The increasing use of enabling technologies, such as microwaves, ultrasound, new heterogeneous catalysts and greener solvents in recent years has made access to coumarin derivatives much simpler. This review will highlight the most recent synthetic advances that make use of non-conventional methods and energy sources and some perspectives for the future, in particular the synthesis of new hybrid molecules bearing a coumarin moiety with a dual mode of biological action.

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Recent advances and perspectives in the synthesis of bioactive coumarins

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.

https://www.mdpi.com/1420-3049/10/8/937/pdf

Reactions of 3-formylchromone with active methylene and methyl compounds and some subsequent reactions of the resulting condensation products.

Different types of 3-substituted 4H-4-oxobenzopyrans were prepared by microwave irradiation as well as by a classical method. The beneficial effect of microwave irradiation on the aldol condensation of 3-formylchromones with 2-imino-1-methylimidazolidine-4-one (creatinine), 2-thioxoimidazolidine-4-one (thiohydantoin) and 2-ethyl-2-thioxothiazolidin-4-one (3-ethylrhodanine) in different reaction media is described. Our results show that the effect of microwave irradiation on the reactions studied was a shortening of the reaction times and a smooth increase in the yields. The subsequent reactions of the product with some nucleophiles are discussed. The structure of the products was proven by elemental analysis, IR and NMR spectra.

https://www.mdpi.com/1420-3049/5/2/167/pdf

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

The aldol synthesis of benzimidazole, benzothiazole and benzothiazolium salt derivatives of chromones is described. The structures of the compounds have been proved by elemental analysis and 1H NMR spectra. The antimycobacterial activity of some of the prepared compounds have been tested in vitro against Mycobacterium tuberculosis (H37Rv) and Mycobacterium fortuitum (1021).

Synthesis and antimycobacterial activity of some new 3-heterocyclic substituted chromones.

A facile route to phenyl, phenylsulfanyl and phenylselanyl substituted pyrano[3,2-c]chromenes

Condensation of 6-R-3-formylchromones ( I ) with 3,3-dimethyl-1,3-cyclohexanedione ( II ), 1,3-indandione ( III ), 1,2e-biindenylidene-3,1e,3e-trione (bindone, IV ), 2-oxo-1,4-benzothiazine ( V ) and 3-oxo-2,3-dihydro-1-thia-3a,8-diazacyclopent[a]indene ( VI ) by the "classical" method, as well as condensation in a microwave oven, has been studied. Some subsequent reactions of these products are described.

Renata Gašparová

Papers

Reactions of 3-formylchromone with active methylene and methyl compounds and some subsequent reactions of the resulting condensation products.

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

Synthesis and antimycobacterial activity of some new 3-heterocyclic substituted chromones.

A facile route to phenyl, phenylsulfanyl and phenylselanyl substituted pyrano[3,2-c]chromenes

Study of Microwave Irradiation Effect on Condensation of 6-R-3-Formylchromones with Active Methylene Compounds