Transformations of N-Heteroarylformamidines and N-Heteroarylformamidine Oximes. New Syntheses and Transformations of Oxazolopyridazines

Article abstract of DOI:10.1007/BF00810484

New syntheses of oxazolo<4,5-d>pyridazine derivatives 7 and 11 were achieved by the cyclization of substituted N-pyridazin-5-ylformamide oximes 6 and 10.Under mild reaction conditions the transformations of the substituted amino group at position 2 of the oxazolo<4,5-d>pyridazine system 7 occured to produce the compounds 11, 14, and 15, 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 compounds 13, 16, 17 and 18. - Keywords: Cyclization with C-O bond formation; Substituted N-pyridazin-5-ylformamidines and -formamide oximes; Oxazolo<4,5-d>pyridazines; Ring opening of oxazolo<4,5-d>pyridazines