FTIR study on nucleotide analogues .1. Spectral characterization of dinucleoside methylphosphonates and dinucleoside 5'-methylenephosphonates in solution and in solid phase

Some conformational feature of dithymidine nucleotides containing natural 3' -> 5' phosphodiester, methylphosphonate, or 5'-methylenephosphonate internucleotidic linkages were probed in solution and in solid phase using FTIR spectroscopy. A high similarity of the IR spectra in the region of 1800-1250 cm(-1) indicates that all the investigated compounds have similar glycosidic torsion angels and the preferred conformation of the deoxyribose rings. However, small but significant differences between the R-P and S-P diastereomers of methylphosphonate analogue 5 may suggest that the association or the hydration mode of these compounds may vary.