Transformations of N-heteroarylformamidines and N-heteroarylformamidine oximes new syntheses and transformations of oxazolo4,5—dpyridazines

摘要

New syntheses of oxazolo4,5—dpyridazine derivatives7and11were achieved by the cyclization of substituted N-pyridazin-5-ylformamide oximes6and10. Under mild reaction conditions the transformations of the substituted amino group at position 2 of the oxazolo4,5—dpyridazine system7occured to produce the compounds11, 14, and15, while under more drastic reaction conditions the nucleophilic attack at carbon at position 2 followed by the ring opening of the oxazole part of the molecule was observed to give the compounds13, 16, 17an