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Chemical Families (chemical + family)

Distribution by Scientific Domains
Chemistry100%

Selected Abstracts

Imidazoline binding sites and their ligands: An overview of the different chemical structures

MEDICINAL RESEARCH REVIEWS, Issue 5 2004
Christophe Dardonville
Abstract Since Bousquet et al. discovered the imidazoline binding sites (IBS) two decades ago, when they realized that the antihypertensive drug clonidine interacts not only with the ,2 -adrenenoceptors (,2 -AR) but also with a distinct imidazoline preferring binding site, these receptors have been paid a great deal of attention. At least two subtypes, I1 and I2, have been characterised based on their binding affinity for different radioligands, but their structures still remain unknown. The pharmacological profile of these IBSs has been the objective of several and very thorough reviews. However, a medicinal chemistry overview of the different IBS ligands prepared to date has never been attempted. In this study, we attempt to compile all the different chemical structures reported to date as IBS ligands and classify them in function of their chemical structure and binding affinity for the different IBS subtypes. Thus, we comment on the different endogenous IBS ligands known as well as the drugs described to interact with the I1 -IBS which have found application as antihypertensive drugs. Then, we review those compounds described in the literature to interact with the I2 -IBS, classifying them by their chemical families (imidazolines, guanidines, 2-aminoimidazolines, ,-carbolines). Finally, some conclusions are drawn. © 2004 Wiley Periodicals, Inc. Med Res Rev, 24, No. 5, 639,661, 2004 [source]

Simple Relationship for Predicting Impact Sensitivity of Nitroaromatics, Nitramines, and Nitroaliphatics

PROPELLANTS, EXPLOSIVES, PYROTECHNICS, Issue 2 2010
Hossein Keshavarz, Mohammad
Abstract This paper describes the development of a simple model for predicting the impact sensitivity of nitroaromatics, benzofuroxans, nitroaromatics with ,-CH, nitramines, nitroaliphatics, nitroaliphatics containing other functional groups, and nitrate energetic compounds using their molecular structures. The model is optimized using a set of 86 explosives for which different structural parameters exist. The model is applied to a test set of 120 explosives from a variety of the mentioned chemical families in order to confirm the reliability of a new method. Elemental composition and two specific structural parameters, that can increase or decrease impact sensitivity, would be needed in this new scheme. The predicted impact sensitivities for both sets have a root mean square (rms) of deviation from experiment of 23,cm, which shows good agreement with respect to the measured values as compared to the best available empirical correlations. [source]

Metabolite profiling in rat urine by liquid chromatography/electrospray ion trap mass spectrometry.

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 22 2003
Application to the study of heavy metal toxicity
This work reports the use of reverse-phase liquid chromatography coupled to electrospray ion trap (QIT) mass spectrometry for the analysis of the metabolome in rat urine. An injection of 20,,L of urine into the chromatographic system is followed by a slow gradient elution and mass spectrometric detection in the scanning mode from m/z 100,1000 in both positive and negative modes. Over a time scale of 90,min, 30 and 20 resolved peaks were observed in the positive and the negative modes, respectively, corresponding to the presence of a few hundred m/z ratios. By using a QIT analyzer, data-dependent tandem mass spectrometry of selected m/z ratios identified several compounds in rat urine and characterized various chemical families, including carboxylic acids, amines, sulfated compounds, glucuronides and glycosides, by the observation of characteristic fragment ions or neutral losses. The method has been applied to the investigation of the chronic toxicity of heavy metals in rat urine. A few tens of m/z ratios, differing in intensity more than threefold from control values, were observed in both positive and negative modes. The time variations for some selected ions suggest that LC/ESI-MS could allow selective characterization of biomarkers in response to specific toxic compounds. Copyright © 2003 John Wiley & Sons, Ltd. [source]

The evolution of volatile compounds profile of "Toscano" dry-cured ham during ripening as revealed by SPME-GC-MS approach,

JOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 9 2010
C. Pugliese
Abstract The volatile compounds profile is an important feature for the characterization of dry-cured hams. Some minor typical Italian products, such as ,Toscano' ham, have been poorly studied in regards to their composition of volatile compounds. In this article, we studied the evolution of the aromatic profile of ,Toscano' dry-cured ham by solid-phase microextraction-gas chromatographic-mass spectrometry (SPME-GC-MS) with ripening. Ten right thighs were cured according to the ,Toscano' PDO protocol, sampled at 0, 1, 3, 6 and 12 months and submitted to volatile compounds analysis by SPME with a Divinylbenzene (DVB)/Carboxen/Polydimethylsiloxane (PDMS) 75-µ Stable Flex fibre. An Agilent 5975C mass selective detector (MSD) spectrometer with electron ionization (EI) source operating in scan mode within the m/z 29,350 range was used for data collection. Seven internal standards, either deuterium labeled or absent in the specimens and chosen to represent low or high boiling esters, alcohols, acids or phenols, were added to the homogenized samples and used to normalize the SPME fibre response to account for response changes upon wearing. Linear calibrations were obtained in this way for selected representative compounds. Over 60 compounds belonging to esters, aldehydes, organic acids, ketones and alcohols were identified by comparison with spectral libraries and Kovats indices. Aldehydes were the most represented chemical family, followed by organic acids, alcohols, ketones and esters. The aldehydes and ketones increased during the first 3 months, when the larger formation of volatiles occurred. For other families, the evolution over time was less evident. The principal component and discriminant analyses of the aromatic profile were effective in classifying the hams at 0, 6 or 12 months of ripening while for 1 and 3 months' samples a partial overlapping was shown. These results represent the first characterization of ,Toscano' ham and may constitute the basis to identify the best ripening time and define an analytical quality standard for this typical ham. Copyright © 2010 John Wiley & Sons, Ltd. [source]