Tetrahydrobenzo- and benzofurobenzopyrones as a new class of potential photoreagents toward DNA

(A) 1FHY-X-ray diffraction. The crystal structures of psoralen cross-linked DNAs: drug-dependent formation of Holiday junctions [J.K. MacLeod, B.R. Worth, Tetrahedron Lett. (1972) 237]; (B) 1FHZ-X-ray diffraction. Structure of psoralen cross-linked DNA: the drug dependent formation of Holiday junctions [J.K. MacLeod, B.R. Worth, Tetrahedron Lett. (1972) 237]; (C) 2B2B-X-ray diffraction, 4′-hydroxy methyl-4,5′,8-trimethylpsoralen. Structural distortion in psoralen cross-linked DNA [F.A. Hays, H. Yonggang, B.F. Eichman, J. Hearst, P.S. Ho].