Preparation of the individual diastereomers of adenylyl-(2′-5′)-P-thioadenylyl-(2′-5′)-adenosine and their 5′-phosphorylated derivatives

The individual diastereomers of trimer A2'p5'A2'p(s)5'A, containing one phosphorothioate linkage, were prepared via a modified hydroxybenzotriazole phosphotriester approach. The 5'-phosphorylated derivatives of the latter compounds were obtained after phosphorylation with a 6-trifluoromethyl-1-benzotriazolyl activated phosphoromorpholidate.