Detalle de: Study of the Rotational Isomerism and Synthesis of Glucosides Derived from Pyrazino[2,3‐ c ][1,2,6]thiadiazine 2,2‐Dioxides

Glucosidations of 4‐amino‐8 H ‐pyrazino[2,3‐ c ][1,2,6]thiadiazine 2,2‐dioxide and its 6,7‐dimethyl‐ and 6,7‐diphenyl derivatives via the “silylation method” are described. The reaction favors N‐1 substitution and the tetra‐ O ‐acetylglucopyranosyl derivatives 5, 6 , and 7 as well as the free nucleosides 8, 9 , and 10 have been isolated and characterized by UV, 1 H, and 2D‐NMR spectroscopy. The latter compound exist at room temperature, as rotationally restricted “ syn‐anti ” isomers, and the free energies of activation have been calculated.