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At least 37 records · Page 2Linked to original sources
PubMed1988

Metabolism of 5-methyl-2-furaldehyde in rat. III. Identification and determination of 5-methyl-2-furylmethylketone.

1. Continuous extraction, column chromatography and t.l.c. were employed to isolate a minor metabolite of 5-methyl-2-furaldehyde from rat urine. 2. The metabolite was identified by mass spectrometry and independent synthesis as 5-methyl-2-furylmethylketone. 3. A method for quantitative determination of the metabolite in urine was devised. About 7% of the parent compound was metabolized to 5-methyl-2-furylmethylketone.

Animals↗
PubMedDate not supplied

Reactivity of 5-nitro-2-furaldehyde in alkaline and acidic solutions.

5-Nitro-2-furaldehyde (NFA) forms in alkaline solutions an anion of nitronic acid of (5-nitro-furan-2-yl)-methanediol. Upon acidification (5-nitro-furan-2-yl)-methanediol (HNFA) appears with pKa=4.6. Then, in a novel irreversible redox ring-opening reaction, nitrile oxide of alpha-ketoglutaconic acid is formed which hydrolyses in acidic solutions. With increasing pH it dimerizes to furoxane or polymerizes to hydraxamates. Some of the products were separated and identified by IR and NMR spectroscopy, confirmed by elemental analysis.

Acids↗
PubMedDate not supplied

Cytotoxicity of copper complexes of 2-furaldehyde oxime derivatives in murine and human tissue cultured cell lines.

The copper complexes of furan oxime derivatives were found to be potent cytotoxic agents in both murine and human tissue cultured cell lines which were either suspended or solid tumors. The ED50 values were frequently improved over the clinically useful antineoplastic agents. These copper complexes of 2-furaldehyde oximes were effective inhibitors of L1210 lymphoid leukemia DNA synthesis followed by RNA synthesis. Purine synthesis regulatory enzyme activities were markedly reduced by the compounds with marginal inhibition of t-RNA polymerase, and nucleoside kinases activities. L1210 DNA topoisomerase II activity was markedly reduced with IC50 values better than the standard VP-16, etoposide. Yet, the copper complexes caused no further protein linked breaks than VP-16 did, but did block phosphorylation activation of the topoisomerase II enzyme.

Animals↗
PubMed2003

Study of a bis-furaldehyde Schiff base copper(II) complex as carrier for preparation of highly selective thiocyanate electrodes.

A new highly selective thiocyanate electrode based on N,N'-bis-(furaldehyde)-1,2-phenylenediamine-dipicolyl copper(II) complex [Cu(II)-BFPD] as neutral carrier is described. The electrode has an anti-Hofmeister selectivity sequence: SCN->I->Sal->ClO4->Br->NO2->Cl->NO3->SO4(2-)>SO3(2-)>H2PO4- and a near-Nernstian potential linear range for thiocyanate from 1.0x10(-1) to 5.0x10(-6) mol L(-1) with a detection limit 2.0x10(-6) mol L(-1) and a slope of 57.5 mV decade(-1) in pH 5.0 of phosphate buffer solution at 20 degrees C. The response mechanism is discussed on the basis of results from A.C. impedance measurement and UV spectroscopy. The anti-Hofmeister behavior of the electrode results from a direct interaction between the central metal and the analyte ion and a steric effect associated with the structure of the carrier. The electrode has the advantages of simplicity, fast response, fair stability and reproducibility, and low detection limit. The selectivity of electrodes based on [Cu(II)-BFPD] exceeds that of classical anion-sensitive membrane electrodes based on ion exchangers such as lipophilic quaternary ammonium or phosphonium salts. Application of the electrode for determination of thiocyanate in waste water samples from a laboratory and a gas factory, and in human urine samples, is reported. The results obtained were fair agreement with the results obtained by HPLC.

Journal Article↗
PubMed1984

Aerobic reduction of 5-nitro-2-furaldehyde semicarbazone by rat liver xanthine dehydrogenase.

Previous work in several laboratories has shown that enzymatic reduction of nitroheterocyclic compounds to reactive but uncharacterized metabolites that damage DNA constitutes an important "activation" step in both bacteria and hypoxic mammalian cells. However, since the known mammalian enzymes having nitroreductase activity are reported to be strongly inhibited by molecular oxygen, the relation of reductive activation to the toxic and mutagenic effects of nitroheterocyclic compounds in intact animals or aerobic cultured cells is unclear. We report here that the process of net nitroreduction of 5-nitro-2-furaldehyde semicarbazone (nitrofurazone) by rat liver xanthine dehydrogenase was considerably less sensitive to inhibition by oxygen than was nitroreduction catalyzed by rat liver or milk xanthine oxidase. The dehydrogenase is the native form of xanthine oxidoreductase and is known to change to the oxidase form as liver extracts are aged or treated with various agents. Incubation at 65 degrees rapidly converted the dehydrogenase form to the oxidase form with concomitant loss of aerobic nitroreductase activity. Similarly, much of the aerobic nitroreductase activity was lost when the preparation was treated with p-hydroxymercuribenzoate but was regained upon subsequent treatment with dithiothreitol. Intermediates generated in the aerobic nitroreduction process bound tightly and probably covalently to protein. Thus, it is possible that aerobic reduction of nitrofurans and other nitroheterocyclic and nitroaromatic components by xanthine dehydrogenase may constitute a significant "activation" process which contributes to the toxic action of such agents.

Aerobiosis↗
PubMed1998

Synthesis and anti-trypanosomal activity of novel 5-nitro-2-furaldehyde and 5-nitrothiophene-2-carboxaldehyde semicarbazone derivatives.

Several novel semicarbazones derivatives were prepared from 5-nitro-2-furaldehyde or 5-nitrothiophene-2-carboxaldehyde, and tested in vitro as potential anti-trypanosomal agents. The compounds were prepared in good to excellent yields in 2-3 steps from readily available starting materials. Some derivatives were found to be active against Trypanosoma cruzi with an activity similar to that of Nifurtimox.

Animals↗
PubMed1991

Degradation of furfural (2-furaldehyde) to methane and carbon dioxide by an anaerobic consortium.

Furfural, a byproduct formed during the thermal/chemical pretreatment of hemicellulosic biomass, was degraded to methane and carbon dioxide under anaerobic conditions. The consortium of anaerobic microbes responsible for the degradation was enriched using small continuously stirred tank reactor (CSTR) systems with daily batch feeding of biomass pretreatment liquor and continuous addition of furfural. Although the continuous infusion of furfural was initially inhibitory to the anaerobic CSTR system, adaptation of the consortium occurred rapidly with high rates of furfural addition. Addition rates of 7.35 mg furfural/700-mL reactor/d resulted in biogas productions of 375%, of that produced in control CSTR systems, fed the biomass pretreatment liquor only. The anaerobic CSTR system fed high levels of furfural was stable, with a sludge pH of 7.1 and methane gas composition of 69%, compared to the control CSTR, which had a pH of 7.2 and 77% methane. CSTR systems in which furfural was continuously added resulted in 80% of the theoretically expected biogas. Intermediates in the anaerobic biodegradation of furfural were determined by spike additions in serum-bottle assays using the enriched consortium from the CSTR systems. Furfural was converted to several intermediates, including furfuryl alcohol, furoic acid, and acetic acid, before final conversion to methane and carbon dioxide.

Acetates↗