RESUMEN
A concise synthesis of phenanthridines via a microwave-assisted [2+2+2] cyclotrimerization reaction has been developed.
Asunto(s)
Fenantridinas/síntesis química , Ciclización , Microondas , Estructura Molecular , Fenantridinas/química , Fenantridinas/efectos de la radiación , EstereoisomerismoRESUMEN
The reaction of 6-acylmethylphenanthridines with isoamyl nitrite results alpha-oximino-6-acylmethylphenanthridines in 73-95% yields in DMF under ultrasound irradiation. Compared with conventional methods, the main advantages of the present procedure are milder conditions, shorter reaction time and higher yields.
Asunto(s)
Oximas/síntesis química , Fenantridinas/síntesis química , Nitrito de Amila/análogos & derivados , Nitrito de Amila/química , Nitrito de Amila/efectos de la radiación , Indicadores y Reactivos , Espectroscopía de Resonancia Magnética , Nitrosación/efectos de la radiación , Fenantridinas/química , Fenantridinas/efectos de la radiación , Espectrofotometría Infrarroja , Sulfatos/química , UltrasonidoRESUMEN
Photoinduced electron transfer from two intercalating photoactive donors, Ru(phen)2dppz2+ and ethidium, to intercalating viologen acceptors of the N,N'-dialkyl-6-(2'-pyridiniumyl)phenanthridinium family has been investigated through steady-state and time-resolved luminescence quenching measurements. Efficient quenching of the emission from these donors bound to DNA is observed at low concentrations of acceptor (1-10 eq.), and in time-resolved emission experiments it is determined that electron transfer occurs on the nanosecond time scale. Furthermore, transient absorption measurements confirm that the quenching is the result of a charge-transfer process; upon photoreaction of intercalated Ru(phen)2dppz2+ with a viologen acceptor, an intermediate with spectral properties resembling the expected charge-separated pair is observed. The quenching yields and kinetics obtained with this quencher are in marked contrast to those observed with these same donors paired with Rh(phi)2bpy3+ as an acceptor. The differing efficiencies of electron transfer for these donor/acceptor pairs bound to DNA as compared to others previously described are discussed qualitatively in terms of the structural and electronic properties of the different reactants.