Abstract Preparation of 2, 3-Dimethyl-5, 6-dihydro-4H-1, 2-oxaziniumiodide was achieved by N-alkylation of 3-methyl-5, 6-dihydro-4H-1, 2-oxazine. Reactions with C-nucleophiles led to the corresponding N-methyl-perhydro-1, 2-oxazine derivatives. Reaction with sodium hydride in triglyme led to 3-methyl-4-aza-1, 3-pentadiene.