Exploiting the dual reactivity of o-isocyanobenzamide: three-component synthesis of 4-imino-4H-3,1-benzoxazines.

[reaction: see text] A multicomponent synthesis of 4-imino-4H-3,1-benzoxazines is developed. Heating a toluene solution of an aldehyde (6), an amine (7), and an isonitrile (5) in the presence of a stoichiometric amount of ammonium chloride at 60 degrees C for 12 h produces the title compound in good to excellent yields.