Solution conformation and dynamics of L ‐6‐methylperhydroimidazo[1,5‐ c ]thiazole‐5,7‐dione (γ‐thiaprolinehydantoin). A 1 H and 13 C NMR study

The solution conformation of L‐6‐methylperhydroimidazo[1,5‐c]thiazole‐5,7‐dione (γ‐thiaprolinehydantoin) has been determined from an extensive 1 H and 13 C NMR study, allowing the extraction of vicinal inter‐proton and carbon‐hydrogen coupling constants. The major conformation of the thiazolidine ring is an envelope with C‐δ as the flap exo (δ − ). In solution the preferred solid state (twist) conformer with C‐α exo and C‐β endo ( α β T) is only a minor contributor. 13 C spin–lattice relaxation data reveal the flexibility of the thiazolidine ring.