ABSTRACT
A concise synthesis of phenanthridines via a microwave-assisted [2+2+2] cyclotrimerization reaction has been developed.
Subject(s)
Phenanthridines/chemical synthesis , Cyclization , Microwaves , Molecular Structure , Phenanthridines/chemistry , Phenanthridines/radiation effects , StereoisomerismABSTRACT
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.
Subject(s)
Oximes/chemical synthesis , Phenanthridines/chemical synthesis , Amyl Nitrite/analogs & derivatives , Amyl Nitrite/chemistry , Amyl Nitrite/radiation effects , Indicators and Reagents , Magnetic Resonance Spectroscopy , Nitrosation/radiation effects , Phenanthridines/chemistry , Phenanthridines/radiation effects , Spectrophotometry, Infrared , Sulfates/chemistry , UltrasonicsABSTRACT
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.
