Direct Thiation of 7-Theophyline Nucleosides

Synthesis of Theophylline and 6‐Thiotheophylline 7‐Ribosyl Nucleosides

“…In this case, treatment of D ‐ribose with 4,5‐diamino‐1,3‐dimethyluracil in methanol yields 17 19. Treatment of this D ‐ribosylidene imino derivative with acetic anhydride in an acid medium at 30 °C affords the 4‐acetylamino derivative 18 in 63% yield, together with the amine 19 in 20% yield, but no ribofuranosyl derivative.…”

“…The synthesis of 7‐(glycosyl)theophylline compounds through the construction of the imidazole ring requires the use of a 4‐amino‐5‐(glycosylamino)pyrimidine as precursor (see Scheme ). These can be synthesised in an almost quantitative yield by condensation of 4,5‐diamino‐1,3‐dimethyluracil with a sugar, in an approach used in our laboratory for the synthesis of 7‐substituted nucleoside derivatives 19−21…”

Applications of Lawesson′s Reagent in Organic and Organometallic Syntheses

“…Protection of the carboxy group of 5-oxo-Lprolin is not necessary, as nucleophilic attack by the carboxy group on LR does not occur at room temperature. Rios-Ruiz and co-workers 83 reported the direct thionation of 7-theophylline nucleosides. They prepared 6-thiothreophylline nucleosides from the corresponding threophylline nucleosides by treatment wit LR in refluxing toluene.…”