Carbon‐13 NMR investigation of the structure of hydroxy‐azoloazines with a bridgehead nitrogen

Carbon‐13 nmr data has been obtained on four hydroxy‐azoloazines containing a bridgehead nitrogen atom, on the corresponding methoxide derivatives, and on selected anionic and cationic derivatives. These results have been interpreted in terms of the site of protonation of the parent hydroxy‐compounds. A comparison of the anionic derivatives with those of the parent compounds demonstrate that the neutral parent hydroxy‐species exist predominately in the “hydroxy form” rather than as the ionized species. The chemical shift data also provides information on the conformation of the hydroxy‐ and methoxy‐groups in 8‐hydroxy‐6‐methyl‐s‐triazolo[4,3‐6]‐pyridazine and 8‐rnethoxy‐6‐methyl‐s‐triazolo[4,3‐6]pyridazine.