title: Photo-C 4 -cycloaddition of psoralen and pyrimidine bases: effect of oxygen and paramagnetic ions.
mesh_terms: D003374:Coumarins; D003500:Cyclization; D005453:Fluorescence; D005663:Furans; D006863:Hydrogen-Ion Concentration; D008722:Methods; D010100:Oxygen; D010777:Photochemistry; D011743:Pyrimidines
chemical_list: D003374:Coumarins; D005663:Furans; D011743:Pyrimidines; D010100:Oxygen