REACTION OF 1-HYDROXYPHTHALIMIDE DERIVATIVES WITH ALUMINUM-CHLORIDE IN BENZENE

The reaction of 1-hydroxyphthalimide derivatives with AlCl3 in benzene has been investigated. From 1-hydroxyphthalimide (la) 2-hydroxy-3,3-d iphenyl-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 im ide carbonyl, assisted by the neighboring oxygen atom. Heating 2 with Lewis acid (AlCl3) in benzene results in ring expansion to afford 3, w hile heating 3 with protic acid (H2SO4) leads to ring contraction to g ive 2. From O-(2-phenethyl)- and O-benzoyl derivatives (Ib and c), 1,2 -diphenylethane (4) and benzophenone (5) are obtained, respectively, b y the heterolytic cleavage of an C-O bond.