Reaction Of 1-Hydroxyphthalimide Derivatives with Aluminum Chloride in Benzene
The reaction of 1-hydroxyphthalimide derivatives with AlCl/sub 3/ in benzene has been investigated. From 1-hydroxyphthalimide (la) 2-hydroxy-3,3-diphenyl-2,3-dihydro-isoindol-1-one (2) and 1,1-diphenyl-1H-benzo[d][1,2]oxazin-4-one (3) are obtained by initial attack of benzene on the imide carbonyl, assisted by the neighboring oxygen atom. Heating 2 with Lewis acid (AlCl/sub 3/) in benzene results in ring expansion to afford 3, while heating 3 with protic acid (H/sub 2/SO/sub 4/) leads to ring contraction to give 2. From O-(2-phenethyl)- and O-benzoyl derivatives (Ib and c), 1,2-diphenylethane (4) and benzophenone (5) are obtained, respectively, by the heterolytic cleavage of an C-O bond.