Rearrangement reactions of a Reissert compound chlorohydrin

Abstract

The Reissert compound, 2-benzoyl-1-cyano-1,2-dihydroisoquinoline, reacted with hypochlorous acid to yield a crystalline chlorohydrin. Base-catalysed elimination of hydrogen chloride from this led to an array of rearranged products in a controlled manner. In this way, simple preparative routes to 1-benzoylamino-1-cyanoisochromene, 1-benzoyliminoisochromene (and thence isocoumarin), 1-ethoxy-4-formyl-3-phenylisoquinoline, and 1-ethoxy-3-phenylisoquinoline were devised. The mechanism of the consecutive rearrangements is discussed.