Reaction of Ethyl Azidoformate with Morpholines

Article abstract of DOI:10.1246/bcsj.53.1189

Ethyl azidoformate (1) reacts rapidly with morpholine to give morpholinium azide and 4-(ethoxycarbonyl)morpholine in good yields.With 4-methylmorpholine (3), however, the azide 1 reacts at 115 deg C with evolution of nitrogen to give formal nitrene-insertion products, 4-methyl-3-(ethoxycarbonylamino)morpholine and 4-(ethoxycarbonylaminomethyl)morpholine.There has not been found any product which might arise from the nitrene-insertion into C-H bond adjacent of oxygen of 3.These results can be accounted for on the basis of the n-donor abilities of heteroatoms, O and N.