Analysis of oligo(deoxynucleoside phosphorothioate)s and their diastereomeric composition, Nucleic Acids Res

Short oligo(deoxynucleoslde phosphorothioate)s were analyzed as a pool of individual diastereomeric species. The composition of such mixtures, deter-mined by means of HPLC, Indicates that consecutive couplings in commonly used phosphoramidite chem-istry lead to Increasing contents of the Rp isomer. Methods of analysis and mathematical basis for diastereomeric composition are discussed. Data pres-ented include all 16 possible combinations of nucleo-sides in dlnucleotide phosphorothioates, as well as examples of trimers and tetramers