Unusual schmidt rearrangement of 7,7a,8,9,10,12-hexahydro benzo[h]pyrrolo[1,2-b]-isoquinoline-7,10-dione

The reaction of 7,7a,8,9,10,12-hexahydrobenzoh]pyrrolo 1,2-b]isoquinoline-7,10-dione 2 with sodium azide in sulfuric acid afforded the unexpected cyano derivative 5 . The proposed structure for 5 is supported by ¹³C nmr, ¹H nmr and HMBC spectra.