Abstract
3-Methyl-(IV and V), 3-chloro-6-methyl-(VI), and 3-methoxy-6-methyl-pyridazine N-oxide (VII), and 6-methyl-3-pyridazinol N-oxide (VIII) were synthesized and the N-oxide group in (IV), (VI), (VII), and (VIII) was proved to be in the same position with respect to the methyl group. This N-oxide group was concluded to be in the position adjacent to the methyl group from the formation of 6-methoxy-3-pyridazinemethanol acetate (XIII) by the reaction of (I) or (VII) with acetic anhydride, formation of (VII) from (VIII) by treatment with methyl iodide and silver oxide, from the comparison of ultraviolet and infrared absorption spectra of (VIII), (X), and 1-hydroxy-3-methoxy-6(1H)-pyridazinone (IX), and by comparison of infrared absorption spectra of (IV), (V), and pyridazine 1-oxide. Consequently, the nitrogen further removed from the methyl group is oxidized in (V). Ultraviolet spectra of several pyridazine N-oxides are also given.
