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En el presente trabajo se examinaron y asignaron los datos espectroscópicos de RMN ¹H y 13C para 5α-androstanos y halo-5α-androstanos con diferentes sustituyentes en las posiciones C-3, C-9, C-11 y C-17, empleando técnicas mono y bidimensionales. El efecto de los sustituyentes en los desplazamientos químicos de 13C se comparó con los valores de la epiandrosterona, usado como compuesto de referencia. Se determinaron las constantes de acoplamiento nJ(19F,13C) para los compuestos 6, 8, 11 y 14 [ABSTRACT FROM AUTHOR]

En el siguiente trabajo se pretende mostrar los resultados obtenidos en la síntesis, caracterización y desarrollo de halo-esteroides con potencial actividad anabólica y/o androgénica a partir de materias primas provenientes de fuentes naturales nacionales. [ABSTRACT FROM AUTHOR]

Quimi-Hib is a conjugate vaccine against Haemophilus influenza type b (Hib) where the Hib antigen is the only one produced by chemical synthesis. NMR has become the alternative of choice for the identity of intermediates during the chemical synthesis of Hib antigen. We explore a rapid quantitative proton magnetic resonance (qHNMR) assay for the determination of N,N-dimethylformamide (DMF) as a residual in one of the critical intermediates. The proposed assay has been shown to be accurate, precise for intermediate precision conditions (relative standard deviation <3% for spectrometer-to-spectrometer variations), specific (no detected interferences), and rugged (percentage difference <3% for day-to-day and spectrometer-to-spectrometer variations). The quantitative NMR assay can replace the common chromatographic methods for monitoring the DMF contents in one crucial step of the synthetic scheme., (Copyright © 2012 John Wiley & Sons, Ltd.)

Gangliosides are membrane-associated glycosphingolipids. N-Acetyl GM3 and N-glycolyl GM3 are two tumor-associated antigens expressed in cancer tissues such as melanoma and mammalian cancer. In order to use these antigens in GM3-based vaccines for patients with early stage cancer, the synthetic version is recommended to avoid the risk of animal virus transmission from the source. However, the isolation of natural gangliosides is of comparative value for the structural characterization. The structures of N-acetyl and N-glycolyl GM3 extracted from dog and horse erythrocytes were evaluated by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and nuclear magnetic resonance techniques; additionally, the natural N-acetyl ganglioside was compared to a synthetic one. In addition to the main compound with C24:0 fatty acid chain, a minor component with an additional unsaturation in the ceramide chain was detected, in both the dog and the horse gangliosides. This paper shows spectroscopic evidence of the aforementioned compounds.

(13)C NMR spectroscopic data for 25 cephalosporin derivatives were assigned by combination of one- and two-dimensional experiments. The effect of the substitution at C-3, C-7 and C-4 acid group positions on the chemical shifts of the cephem nucleus is discussed., (Copyright (c) 2007 John Wiley & Sons, Ltd.)