Vibrational study of 5-iodo-2′-deoxyuridine, IDU

The experimental FTIR and FT-Raman spectra of the antiviral nucleoside analogue 5-iodo-2'-deoxyuridine (IDU) were assigned on the basis of normal coordinate analyses carried out by two different procedures, based on the Wilson GF method: a) using a valency force field transferred from molecular fragments and b) the semiempirical molecular orbital (MO) method, PM3. Assignments are discussed in the light of observed and calculated wavenumbers and isotopic shifts. The results indicate that virtually all normal modes of 5-iodo-2'-deoxyuridine involve some degree of vibrational coupling between the iodouracil base and the deoxyribose moiety. The advantages of both methods for obtaining a reliable assignment of the vibrational spectra of IDU are evaluated as a basis for the study of and drug-target interactions. (C) 1999 Elsevier Science B.V. All rights reserved.