S–Co(II) cascade catalysis: cyclocondensation of aromatic nitriles with alkamine

A solvent-free S/Co(NO3)2 cascade catalyzed cyclocondensation reaction of aromatic nitriles with 3-amino-1-propanol or 2-aminoethanol has been successfully developed under thermal and microwave conditions. By this two-component protocol, mono- and bis-oxazines and oxazolines were selectively synthesized both in good to excellent yields and short reaction times. This catalytic system exhibits excellent chemoselectivity, and can be reused at least seven times without significant loss of activity in subsequent reactions.