One-Pot Hydrogen Peroxide and Hydrohalic Acid Induced Ring Closure and Selective Aromatic Halogenation To Give New Ring-Fused Benzimidazoles

A new series of selectively dichlorinated and dibrominated five- to eight-membered-ring [1,2-a]-fused benzimidazoles and [1,4]­oxazino­[4,3-a]­benzimidazoles are synthesized in mostly high yields of >80% using the reaction of hydrogen peroxide and hydrohalic acid with commercially available o-cyclic amine substituted anilines. Domestic bleach with HCl can also be used for a one-pot ring closure and chlorination.