Conversion of indones to quinoline and isoquinoline derivatives—III : Schmidt reaction with 2,3-diphenylindone and similar compounds

Abstract

The Schmidt reaction with 2,3-diphenylindone, in a mixture of sulphuric and acetic acid, affords 3,4-diphenylcarbostyril (A 1), 3,4-diphenylisocarbostyril (A 2), 5-phenyl-11 H-indolo[3.2- c]-isoquinoline (B 1) and 3-( o-aminophenyl)4-phenylisocarbostyril (B 2). The probable mechanism of formation of the four products is discussed. The same reaction, if carried out in sulphuric acid, gives 3-( p-sulphophenyl)4-phenylcarbostyril as the only reaction product. The Schmidt reaction with 3-methyl-2-phenylindone and 3-ethyl-2-phenylindone is also described.