Detalle de: Glycosylation of Pyrazino[2,3‐ c ]‐1,2,6‐thiadiazine 2,2‐Dioxides to Sulfur Dioxide Analogs of Pteridine Nucleosides

Pyrazino[2,3‐ c ]‐1,2,6‐thiadiazine 2,2‐dioxides 1, 2 , and 3 have been glycosylated as their trimethylsilyl derivatives with 1‐ O ‐acetyl derivatives of ribose. 1 leads to mixtures of N ‐1 and N ‐8 monoribosides and N ‐1,4‐ N diribosides, the relative proportions depending on the reaction conditions used. However, in the case of 6,7‐disubstituted pyrazinothiadiazines 2 and 3 only the N ‐1 monoribosides have been obtained. The structures of the newly synthesized compounds are discussed on the basis of UV, 1 H NMR and 2D homonuclear NMR data.