Selectivity of methylation of some new [1,2,3]triazolo[4,5-d]pyridazines and structure elucidation by 1H-15N NMR spectroscopy

Alkylation of some selected [1,2,3]triazolo[4,5-d]pyridazines having five or more nitrogen atoms capable for alkylation was investigated. Pyridyl derivatives substituted also on the [1,2,3]triazole ring gave quaternary pyridinium salts, whereas in the case of the analogues compounds unsubstituted at the triazole moiety, the alkylation of the triazole ring was also observed. nambiguous structure elucidation was provided by H-1-N-15 HMBC experiments which also allowed the assignment of the N-15 NMR shifts. (C) 2002 Elsevier Science B.V. All rights reserved.