RESUMEN
The functionalization of single-walled carbon nanotubes (SWCNTs) via microwave-assisted grafting reactions enables efficient multidecoration in a single step. A novel water-soluble SWCNT platform was prepared via the simple 1,3-dipolar cycloaddition of azomethine ylides under dielectric heating. Thanks to a single grafting reaction the CNT surface binds in a 1 : 1 ratio an amino acidic ß-cyclodextrin (ß-CD) derivative and the DOTAMA moiety (1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid monoamide). This novel "one shot" synthesis, compared with multistep functionalizations, preserves the SWCNT's structural integrity (TEM images). Besides thermogravimetric analyses, the determination of the amount of ß-CD and DOTA moieties grafting onto the SWCNT's surface was performed on the basis of phenolphthalein and gadolinium complexation, respectively.
Asunto(s)
Química Orgánica/métodos , Compuestos Heterocíclicos con 1 Anillo/química , Microondas , Nanotubos de Carbono/química , beta-Ciclodextrinas/química , Línea Celular Tumoral , Supervivencia Celular , Reacción de Cicloadición , Descarboxilación , Humanos , Nanotubos de Carbono/ultraestructura , Espectrofotometría Ultravioleta , Temperatura , beta-Ciclodextrinas/síntesis químicaRESUMEN
New highly soluble ß-aminoalcohol ß-cyclodextrin (ß-CD) derivatives have been synthesized via nucleophilic epoxide opening reactions with mono-6-amino mono-6-deoxy-permethyl-ß-CD and mono-6-amino mono-6-deoxy-ß-CD. The binding properties of the ß-CD were enhanced by linking aminoalcohol subunits which caused its solubility to improve markedly. The reaction conditions were optimised using microwave irradiation giving moderate-to-good yields with a series of epoxides. A regioselective epoxide opening reaction was observed in the reaction with styrene oxide while the stereoselectivity was strictly dependent on substrate structure.
Asunto(s)
Compuestos Epoxi/química , Solventes/química , Agua/química , beta-Ciclodextrinas/síntesis química , Alquenos/química , Glicoles de Etileno/química , Microondas , Solubilidad , beta-Ciclodextrinas/química , beta-Ciclodextrinas/aislamiento & purificaciónRESUMEN
The antithrombinic activity of some naturally occurring omega-oxygenated derivatives of ferulenol and ferprenin has been tested. On the basis of these results, both the type of the oxygenated function and the stereochemistry of the terminal double bond seem important for the biological activity.
Asunto(s)
Anticoagulantes , Cumarinas/aislamiento & purificación , Plantas Tóxicas/análisis , Animales , Cumarinas/toxicidad , Masculino , Tiempo de Protrombina , Ratas , Ratas Endogámicas , Estereoisomerismo , Warfarina/farmacologíaRESUMEN
The study of two chemically characterized varieties of Ferula communis showed that only plants containing prenylated coumarins are toxic. The contrasting data on the toxicity of Ferula communis most probably raised from the use of chemically uncharacterized specimens. Among the constituents of the toxic variety, both ferulenol, a 4-hydroxycoumarin derivative, and ferprenin, a pyrane (3,2-c) coumarin derivative, affected blood clotting. No hepatotoxicity was elicited by these two compounds.