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Compound N (compound + n)

Distribution by Scientific Domains

Life Sciences	50%
Chemistry	50%

Selected Abstracts

Solid-State Structure and Tautomerism of 2-Aminotroponimines Studied by X-ray Crystallography and Multinuclear NMR Spectroscopy

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 21 2004
Rosa M. Claramunt
Abstract Structural studies in the solid state by X-ray crystallography and by 13C and 15N CPMAS NMR spectroscopy carried out on a series of 2-aminotroponimine derivatives 2,5 has allowed to establish the existence of hydrogen bonding and to determine the most stable tautomer. Almost all the structures reflect the classical double-well potential function for the N,H···N hydrogen bonds. Only in the case of the compound N -(pyrrol-1-yl)-2-(pyrrol-1-ylamino)troponimine (5) the crystal structure shows two independent molecules, one with a classical hydrogen bond and another with either a single-well or a low-barrier hydrogen bond. The structure of this compound is discussed with the use of the solid-state NMR spectroscopic data. 2-Aminotropones, as intermediates to the 2-aminotroponimines, show the oxo-tautomer as the stable form. B3LYP/6-31G* calculations are used to rationalise the experimental results. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source]

Systemic plant signal triggers genome instability

THE PLANT JOURNAL, Issue 1 2004
Jody Filkowski
Summary Previously, we have shown that infection of tobacco plants with a viral pathogen triggers local and systemic induction of homologous recombination (HR). Here, we have tested the hypothesis of whether free radicals are potentially involved in the induction of the systemic effect. We report a significant induction of HR in tobacco plants treated with radical-generating agents, UVC or rose Bengal (RB). Importantly, the recombination increase was observed in local (treated) as well as systemic (non-treated) tissue. The systemic increase in recombination implies the existence of a signal that is transmitted to non-treated tissue. Several sets of grafting experiments proved the generation of said signal by both RB and UVC exposure. A statistically significant increase in HR was observed in tissue that received a systemic signal via a grafted leaf. Similar data were obtained from transgenic plants naphthalene degrading salicylate 1-hydroxylase (NahG) unable to accumulate salicylic acid (SA). Interestingly, pre-treatment of plants with the radical-scavenging compound N -acetyl- l -cysteine (NAC) led to a significantly lower recombination increase upon grafting after treatment with UVC and RB. Moreover, leaves taken for grafting from NAC-pre-treated plants exhibited a lower level of oxidized organic compounds. Our data suggest the involvement of free radical production in either generation or maintenance of the recombination signal. We discuss potential mechanisms for generation of the signal and possible adaptive advantages of enhanced genomic flexibility following exposure to DNA-damaging agents. [source]

Gas chromatography,mass spectrometry analysis of endogenous cannabinoids in healthy and tumoral human brain and human cells in culture

JOURNAL OF NEUROCHEMISTRY, Issue 2 2001
Mauro Maccarrone
Endocannabinoids are lipid mediators thought to modulate central and peripheral neural functions. We report here gas chromatography,electron impact mass spectrometry analysis of human brain, showing that lipid extracts contain anandamide and 2-arachidonoylglycerol (2-AG), the most active endocannabinoids known to date. Human brain also contained the endocannabinoid-like compounds N -oleoylethanolamine, N -palmitoylethanolamine and N -stearoylethanolamine. Anandamide and 2-AG (0.16 ± 0.05 and 0.10 ± 0.05 nmol/mg protein, respectively) represented 7.7% and 4.8% of total endocannabinoid-like compounds, respectively. N -Palmitoyethanolamine was the most abundant (50%), followed by N -oleoyl (23.6%) and N -stearoyl (13.9%) ethanolamines. A similar composition in endocannabinoid-like compounds was found in human neuroblastoma CHP100 and lymphoma U937 cells, and also in rat brain. Remarkably, human meningioma specimens showed an approximately six-fold smaller content of all N -acylethanolamines, but not of 2-AG, and a similar decrease was observed in a human glioblastoma. These ex vivo results fully support the purported roles of endocannabinoids in the nervous system. [source]

N -Glucosyl-1H -indole Derivatives from Cortinarius brunneus (Basidiomycetes)

CHEMISTRY & BIODIVERSITY, Issue 4 2008
Axel Teichert
Abstract Two new N -glucosylated indole alkaloids were isolated from fruiting bodies of the basidiomycete Cortinarius brunneus (Pers.) Fr. The structures were elucidated by means of the spectroscopic data. Additionally, the very recently reported compounds N- 1 -,- glucopyranosyl-3-(carboxymethyl)-1H -indole (3) and N- 1 -,- glucopyranosyl-3-(2-methoxy-2-oxoethyl)-1H -indole (4) could be detected. Compound 3 is the N -glucoside of the plant-growth regulator 1H -indole-3-acetic acid (IAA), but, in contrast, it does not exhibit auxin-like activity in an Arabidopsis thaliana tap root elongation assay. [source]