ynthesis, spectral analysis and bioactivity of new coumarin derivatives are described in this paper. Eight new coumarin derivatives were synthesized in moderate to good yields by condensation of 4-chloro-3-nitrocoumarin and the corresponding heteroarylamine. The synthesized compounds were tested for their in vitro antimicrobial activity, in a standard disk diffusion assay, against thirteen strains of bacteria and three fungal strains. They have shown a wide range of activity - from one completely inactive compound to medium active ones.

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Herein, we describe the synthesis and complete assignment of the (1)H and (13)C NMR chemical shifts of a series of antimicrobial 4-arylamino-3-nitrocoumarin derivatives based on a combination of (1)H and (13)C NMR, (1)H-(1)H-COSY, NOESY, HSQC and HMBC experiments. Conformational effects upon the chemical shifts of the coumarin moiety arising from the anisotropy of the aryl side group are briefly discussed. This study provides the first complete and fully assigned NMR data for this important group of antimicrobial compounds and bridges the gap existing in the literature with regard to NMR structural data for 4-arylamino-3-nitrocoumarins.

Condensation of 4-chloro-2-oxo-2H-chromene-3-carbonitrile with selected heteroarylamines in acetonitrile containing a catalytic amount of triethylamine, followed by intramolecular cyclization, gave the new coumarin derivatives with yields ranging from 43 % to 78 %. The novel compounds were subjected to acid hydrolysis giving the corresponding oxo derivatives in 66–70 % yield. The structural assignments of the synthesized compounds were based on elemental, IR, 1H and 13C NMR analyses.

The content of phytochemicals, total phenolics, total flavonoids and antioxidant potential of extracts of Juniperus communis L. and Juniperus oxycedrus L. berries were determined. Ethanol, ethyl acetate and chloroform were used for the process of extraction. Phytochemical monitoring was based on already known methods, while in vitro antioxidant activities were done by DPPH assay. Phytochemical screening showed a wide spectrum of phytochemicals. Ethanolic extract of Juniperus communis L. possesses the strongest antioxidant activity (IC50 = 28.55 ± 0.24 µ/ml), as well the higher contents of total phenolics, 189.82 ± 0.27 mg of gallic acid equivalent per g of dried weight extract (mg GAE/g extract DW), and total flavonoids, 42.85 ± 0.13 mg of rutin equivalents per g of dried weight extract (mg RE/g extract DW). The results indicated the potential application of the tested extracts as significant antioxidants.