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1.
J Proteome Res ; 15(9): 3241-54, 2016 09 02.
Artículo en Inglés | MEDLINE | ID: mdl-27518853

RESUMEN

Starvation is a postabsorptive condition derived from a limitation on food resources by external factors. Energy homeostasis is maintained under this condition by using sources other than glucose via adaptive mechanisms. After refeeding, when food is available, other adaptive processes are linked to energy balance. However, less has been reported about the physiological mechanisms present as a result of these conditions, considering the rat as a supraorganism. Metabolic profiling using (1)H nuclear magnetic resonance spectroscopy was used to characterize the physiological metabolic differences in urine specimens collected under starved, refed, and recovered conditions. In addition, because starvation induced lack of faecal production and not all animals produced faeces during refeeding, 24 h pooled faecal water samples were also analyzed. Urinary metabolites upregulated by starvation included 2-butanamidoacetate, 3-hydroxyisovalerate, ketoleucine, methylmalonate, p-cresyl glucuronide, p-cresyl sulfate, phenylacetylglycine, pseudouridine, creatinine, taurine, and N-acetyl glycoprotein, which were related to renal and skeletal muscle function, ß-oxidation, turnover of proteins and RNA, and host-microbial interactions. Food-derived metabolites, including gut microbial cometabolites, and tricarboxylic acid cycle intermediates were upregulated under refed and recovered conditions, which characterized anabolic urinary metabotypes. The upregulation of creatine and pantothenate indicated an absorptive state after refeeding. Fecal short chain fatty acids, 3-(3-hydroxyphenyl)propionate, lactate, and acetoin provided additional information about the combinatorial metabolism between the host and gut microbiota. This investigation contributes to allow a deeper understanding of physiological responses associated with starvation and refeeding.


Asunto(s)
Metabolómica/métodos , Síndrome de Realimentación/orina , Inanición/orina , Estrés Fisiológico , Animales , Creatina , Metabolismo Energético , Microbioma Gastrointestinal , Espectroscopía de Resonancia Magnética , Metaboloma/fisiología , Ácido Pantoténico , Ratas , Síndrome de Realimentación/metabolismo , Síndrome de Realimentación/fisiopatología , Inanición/metabolismo , Inanición/fisiopatología , Orina/química
2.
Magn Reson Chem ; 51(4): 245-50, 2013 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-23436543

RESUMEN

Complete assignment of the (1)H NMR chemical shift and coupling constant values of perezone (1), O-methylperezone (2) and 6-hydroxyperezone (3) was carried out by total-line-shape-fitting calculations using the PERCH iterative spectra analysis software (PERCH Solutions Ltd., Kuopio, Finland). The resulting simulated spectra for the three compounds showed strong similarity to their corresponding experimental spectra. Particularly, all vicinal, allylic and homoallylic coupling constant values for the side chain of the three compounds were very similar, thus revealing that the conformation of these three molecules in solution is indeed almost identical. This fact is in agreement with extended side chain conformations over folded chain conformations because 1, 2 and 3 undergo completely different intramolecular cycloaddition reactions. In addition, results of double pulsed field gradient spin echo NOESY 1D experiments performed on perezone (1) were unable to provide evidence for folded conformers.


Asunto(s)
Sesquiterpenos/análisis , Espectroscopía de Resonancia Magnética , Conformación Molecular , Estándares de Referencia , Programas Informáticos
3.
J Org Chem ; 77(4): 1640-52, 2012 Feb 17.
Artículo en Inglés | MEDLINE | ID: mdl-22217094

RESUMEN

Benzoyl-S,O-acetals 1a and 1b were used as chiral auxiliaries to achieve the diastereoselective preparation of both enantiomers of 2-methoxy-2-phenylpent-3-ynoic acids (MPPAs). The latter were condensed with several chiral secondary alcohols and some primary amines to evaluate their potential as chiral derivatizing agents (CDAs). The (1)H NMR spectra of the corresponding esters and amides showed strong consistency with the absolute configuration of the carbinol and amine moieties, whose observed ΔδL(1) and ΔδL(2) values were in the ranges of 0.1-0.4 and 0.02-0.12 ppm, respectively.


Asunto(s)
Acetales/química , Alcoholes/química , Aminas/química , Ácidos Pentanoicos/síntesis química , Amidas/química , Ésteres/química , Espectroscopía de Resonancia Magnética , Metanol/química , Modelos Moleculares , Estructura Molecular , Ácidos Pentanoicos/química , Estereoisomerismo , Termodinámica
4.
Molecules ; 17(12): 13864-78, 2012 Nov 22.
Artículo en Inglés | MEDLINE | ID: mdl-23174902

RESUMEN

The Weinreb amides 2a,b were prepared from the α,α-dimethoxyacetic acids 1c,d. A number of representative nucleophilic additions (RMgX and RLi) on 2 afforded α-ketoacetals 3a-j in 70-99% yield. These compounds represent a versatile arrangement of functional groups of significant synthetic value, as demonstrated in the synthesis of (±)-salbutamol.


Asunto(s)
Albuterol/síntesis química , Amidas/síntesis química , Cetonas/síntesis química , Estructura Molecular , Estereoisomerismo
5.
Org Lett ; 9(1): 13-6, 2007 Jan 04.
Artículo en Inglés | MEDLINE | ID: mdl-17192073

RESUMEN

[reaction: see text] The new macrocycle 9 (>70% yield from hydroxythiol 10) was treated with several nucleophilic reagents (RMgX, RLi, and LiAlH4) affording carbinols 12a-j (80-96% yield, >99:1 dr). Oxidative hydrolysis of 12a,c,e, followed by LiAlH4 reduction of the resulting mixture, gave 16a,c,e in >95% ee,16c being a key precursor for the preparation of fungicide 17. The absolute configuration of 9 and 12j (Nu = H) was established by single-crystal X-ray diffraction analyses and chemical correlation.

6.
J Agric Food Chem ; 61(49): 11995-2004, 2013 Dec 11.
Artículo en Inglés | MEDLINE | ID: mdl-24168389

RESUMEN

Betalains were extracted and analyzed from Opuntia joconostle (the prickly pear known as xoconostle in Mexico). For the extraction, two solvent systems were used, methanol/water and ethanol/water. A three-variable Box-Behnken statistical design was used for extraction: solvent concentration (0-80%, v/v), temperature (5-30 °C), and treatment time (10-30 min). The extraction and stability of betalains from xoconostle were studied using response surface methodology (RSM). Techniques such as UV-vis, column chromatography, and HPLC were employed for the separation and analysis of the main pigments present in the extracts. Maximum pigment concentration (92 mg/100 g of fruit) was obtained at a temperature of 15 °C and a time of 10 min for methanol/water (20:80), whereas maximum stability of the pigment was observed at pH 5 and a temperature of 25 °C. HPLC chromatograms showed the main betalains of the xoconostle characterized were betalain, betanidin, and isobetalain.


Asunto(s)
Betalaínas/química , Betalaínas/aislamiento & purificación , Frutas/química , Opuntia/química , Extractos Vegetales/química , Extractos Vegetales/aislamiento & purificación , Antioxidantes/química , Antioxidantes/aislamiento & purificación , Cromatografía , Cromatografía Líquida de Alta Presión
7.
Nat Prod Commun ; 6(4): 429-32, 2011 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-21560753

RESUMEN

This communication highlights the need of building hierarchical digraphs for the unequivocal assignment of stereochemical descriptors of (-)-myrtenal, a naturally-occurring oxygenated monoterpene whose absolute configuration (AC) is sometimes misrepresented in its structural formulae. Differentiation between duplicated atoms and phantom atoms for the proper application of the sequence rules is shown to be an essential step to get a proper construction of hierarchical digraphs.


Asunto(s)
Terpenos/química , Monoterpenos Bicíclicos , Conformación Molecular
8.
Phytochemistry ; 71(10): 1158-61, 2010 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-20457457

RESUMEN

The VCD spectrum of the monoterpene (-)-myrtenal (1) was compared with theoretical spectra using ab initio density functional theory (DFT) calculations at the B3LYP/6-31G(d,p), B3LYP/6-31G+(d,p), B3LYP/6-311G+(d,p), B3LYP/DGDZVP, and B3PW91/DGTZVP levels of theory. Conformational analysis of 1 indicated that the lowest energy conformer was s-trans-C2-C10, which contributes more than 98.5% to the total conformational population regardless of the employed level of theory. The use of a recently developed confidence level algorithm demonstrated that VCD spectra calculated for the main conformer, using the indicated hybrid functionals and basis set, gave no significant changes, from where it follows that B3LYP/DGDZVP calculations provide a superior balance between computer cost and VCD spectral accuracy. The DGDZVP basis set demanded around a quarter the time than the 6-311G+(d,p) basis set while providing similar results. The spectral comparison also provided evidence that the levorotatory enantiomer of myrtenal has the 1R absolute configuration.


Asunto(s)
Terpenos/química , Algoritmos , Monoterpenos Bicíclicos , Dicroismo Circular , Modelos Moleculares , Conformación Molecular , Vibración
9.
Mol Divers ; 9(4): 361-9, 2005.
Artículo en Inglés | MEDLINE | ID: mdl-16311813

RESUMEN

A versatile route to 40-membered library of 2-long alkyl chain substituted benzoazoles (1 and 2) and azole[4,5-b]pyridines (3 and 4) via microwave-assisted combinatorial synthesis was developed. The reactions were carried out in both monomode and multimode microwave oven. With the latter, all reactions were performed in high-throughput experimental settings consisting of an 8 x 5 combinatorial library designed to synthesize 40 compounds. Each step, from the addition of reagents to the recovery of final products, was automated. The microwave-assisted N-long chain alkylation reactions of 2-alkyl-1H-benzimidazole (1) and 2-alkyl-1H-benzimidazole[4,5-b] pyridines (3) were also studied.


Asunto(s)
Azoles/síntesis química , Técnicas Químicas Combinatorias , Microondas , Piridinas/síntesis química , Alquilación , Azoles/química , Piridinas/química
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