Isolation and characterization of two furan-side photoadducts of 7-methylpyrido[3,4-c] psoralen to the sugar moiety of 2′-deoxyadenosine

Article abstract of DOI:10.1111/j.1751-1097.1999.tb07983.x

The UVA-mediated photoreaction of the monofunctional 7-methylpyrido[3,4-c]psoralen (MePyPs) with 2′-deoxyadenosine was investigated in the dry state. Two main 7-methylpyrido[3,4-c]psoralen monoadducts to 2′-deoxyadenosine were isolated by HPLC and characterized by soft ionization mass spectrometry (fast atom bombardment) and extensive ¹H NMR analyses including correlation spectroscopy, total correlation spectroscopy and nuclear Overhauser effect measurements. The two unusual photoadducts exhibit a covalent bond between the C-4′ of the furan moiety of the psoralen on one hand and either the C-1′ or the C-4′ of the furanose ring of the purine nucleoside on the other hand. The furan-side monoadducts appear to be specific for both 2′-deoxyadenosine and MePyPs. They are likely to result from the recombination of the 4′,5′-dihydrofuran-4′-yl radical of MePyPs with 2′-deoxyadenosyl carbon-centered sugar radicals at either the 1′ or the 5′ position.