FTIR STUDY ON NUCLEOTIDE ANALOGS .1. SPECTRAL CHARACTERIZATION OF DINUCLEOSIDE METHYLPHOSPHONATES AND DINUCLEOSIDE 5'-METHYLENEPHOSPHONATESIN SOLUTION AND IN SOLID-PHASE

Some conformational feature of dithymidine nucleotides containing natu ral 3' -> 5' phosphodiester, methylphosphonate, or 5'-methylenephospho nate internucleotidic linkages were probed in solution and in solid ph ase using FTIR spectroscopy. A high similarity of the IR spectra in th e region of 1800-1250 cm(-1) indicates that all the investigated compo unds have similar glycosidic torsion angels and the preferred conforma tion of the deoxyribose rings. However, small but significant differen ces between the R-P and S-P diastereomers of methylphosphonate analogu e 5 may suggest that the association or the hydration mode of these co mpounds may vary.