Synthesis of new antimicrobial 4-aminosubstituted 3-nitrocoumarins

A series of new coumarin derivatives has been synthesized by condensation of 4-chloro-3-nitrocoumarin and the appropriate arylamine and sulfonamide in ethyl acetate in the presence of triethylamine. The synthesized compounds were screened for their in vitro antimicrobial activity against thirteen strains of bacteria and three fungal/yeast strains using disk diffusion assays. They were shown to possess a wide range of activities from almost completely inactive compounds to medium active ones. (4-[(5-Chloropyridin-2-yl)amino]-3-nitro-2H-chromen-2-one) showed similar activity against Klebsiella pneumoniae as tetracycline. © 2009 Institute of Chemistry, Slovak Academy of Sciences

Complete assignment of the ¹H and ¹³C NMR spectra of antimicrobial 4-arylamino- 3-nitrocoumarin derivatives

Herein, we describe the synthesis and complete assignment of the 1H and 13C NMR chemical shifts of a series of antimicrobial 4-arylamino-3-nitrocoumarin derivatives based on a combination of 1H and 13C NMR, 1H-1H-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. Copyright © 2010 John Wiley & Sons, Ltd

Influence of the aryl substituent identity in 4-arylamino- 3-nitrocoumarins on their antimicrobial activity

Two new and six previously known coumarin derivatives with promising biological properties were synthesized in moderate to good yields by reaction of 4-chloro-3-nitro-coumarin and the appropriate arylamine in ethyl acetate in the presence of triethylamine. The synthesized compounds were evaluated for their in vitro antibacterial and antifungal activities against pathogenic strains. A correlation between the aryl substituent identity and antimicrobial activity was discussed. © 2011 Academic Journals

isparljivi PROIZVODI razlaganja glukozinolata i ETARSKO ULJE VRSTE dESCURAINIA SOPHIA WEB EX PRANTL (BRASSICACEAE)

Volatile constituents obtained by autolysis of aerial and underground parts of D. sophia and the essential oil obtained by hydrodistillation of whole plant samples were analyzed in detail by GC and GC-MS. In total, 71 constituents were identified, accounting for more than 90% of the total peak areas in the chromatograms. Both aerial and underground autolysates contained considerable amounts of lignan arctigenin and cuticular wax compounds. The essential oil was dominated by glucosinolate breakdown product 4-pentenenitrile. Glucosinolate degradation products identified in the essential oil and autolysates, 3-butenyl isothiocyanate, 4-pentenenitrile and allyl isothiocyanate, suggested the presence of gluconapin and sinigrin in this species as the most likely “mustard oil” precursors.HIGHLIGHTSVolatile constituents of Descurainia sophia essential oil and autolysates were analyzed in detail by GC and GC-MS.The analyses allowed the identification of 71 compounds in total.Descurainia sophia contains glucosinolates gluconapin and sinigrin and lignan arctigenin. Detaljnim GC i GC-MS analizama etarskog ulja i isparljivih sastojaka dobijenih autolizom nadzemnog dela i korena vrste Descurainia sophia identifikovano je ukupno 71 jedinjenje, odnosno više od 90% ukupno detektovanih pikova hromatograma. Oba autolizata su sadržala znatne količine sastojaka kutikularnog voska i lignana arktigenina. Najzastupljeniji sastojak etarskog ulja je bio proizvod razlaganja glukozinolata 4-pentenonitril. Degradacioni proizvodi glukozinolata identifikovani u autolizatima i etarskom ulju, 3-butenil-izotiocijanat, 4-pentenonitril i alil-izotiocijanat, ukazuju na prisustvo glukonapina i sinigrina u tkivima ove biljne vrste

Effect of gamma-irradiation on the hydrolytic stability and thermo-oxidative behavior of bio/inorganic modified urea-formaldehyde resins

In order to minimize emission of formaldehyde from urea formaldehyde resins (UF) and to improve their thermo-oxidative behavior, the effect of low gamma-irradiation on hydrolytic and thermo-oxidative stability of nano-silica modified UF resin, modified UF resin with wood flour (Pinus silvestris L.) as natural filler and modified UF resin with mixture of SiO2/WF fillers were investigated. The hydrolytic stability of modified UF resins was determined by measuring the mass loss and liberated formaldehyde concentration of modified UF resins after acid hydrolysis. The studied modified UF resins have been irradiated (50 kGy) and effect of gamma-irradiation was evaluated on the basis of percentage of liberated formaldehyde before and after irradiation. The minimum percentage (1.23%) of liberated formaldehyde and mass loss of a 25.35% were obtained in wood flour modified UF resin after 7-irradiation which indicate significant improvement in the hydrolytic stability compared to other modified UF resins. The effect of gamma-irradiation was evaluated also on the basis of thermo-oxidative behavior of the same modified UF resins before and after irradiation. The thermo-oxidative behavior was studied by non-isothermal thermo-gravimetric analysis (TG), differential thermo-gravimetly (DTG) and differential thermal analysis (DTA) supported by data from IR spectroscopy. After gamma-irradiation, the shift of DTA peaks a higher temperature indicates that thermo-oxidative stability of modified UF/SiO2/WF is increase. (C) 2014 Elsevier Ltd. All rights reserved

Effect of gamma-irradiation on the hydrolytic and thermal stability of micro- and nano-TiO2 based urea-formaldehyde composites

The hydrolytic stability and thermal behavior of organic-inorganic composites prepared by two-stage polymerization of urea-formaldehyde resin (UF) with micro-and nano-TiO2 before and after irradiation has been investigated. Composites of urea-formaldehyde and particles of TiO2 of different sizes were synthesized, namely: UF/micro-TiO2 and UF/nano-TiO2. The hydrolytic stability of the modified UF composites was determined by measuring the mass loss and liberated formaldehyde concentration of modified UF composites after acid hydrolysis. The studied modified UF composites have been irradiated (50 kGy) and the effect of gamma-irradiation was evaluated on the basis of the percentage of liberated formaldehyde before and after irradiation. The minimum percentage (0.16%) of liberated formaldehyde was obtained in nano-TiO2 modified UF resin after gamma-irradiation which indicated a significant improvement in the hydrolytic stability compared with micro-TiO2 modified UF resin (0.52%). The effect of gamma-irradiation was evaluated also on the basis of the thermal behavior of the same modified UF composites before and after irradiation. The thermal behavior was studied by non-isothermal thermogravimetric analysis (TG), differential thermo-gravimetry (DTG) and differential thermal analysis (DTA) supported by data from attenuated total reflection infrared (ATR-IR) spectroscopy. DTG peaks of both composites are shifted to a higher temperature after irradiation, but UF/micro-TiO2 after gamma-irradiation shows less change in the thermal behavior than nano-TiO2. In other words, UF/micro-TiO2 shows better radiation stability. Gamma irradiation causes a minor effect on the ATR-IR spectra, specifically the decrease of the intensities of some bands