A Novel [3,3]-Rearrangement of 1,2-Dihydro(N-arylamino)pyridines: Formation of Unusual Fused Indolines Summary: Treatment of N-(N-aryl-N-mesy1amino)pyridiniums with base leads to the 1,2-dihydropyridines which undergo a [3,3]-rearrangement and ring closure to give the bridged tetrahydro-a-carbolines 3, whose structures were established by NMR spectroscopy and singlecrystal X-ray crystallography and by reduction to the interesting nine-membered ring compound 8.Sir: The addition of suitable bifunctional reagents to pyridine 1-oxides gives the unstable 1,2-dihydropyridine 1-oxides, which rearrange in a number of ways: 1,3-, 1,5-, and 3,5-shifts.l N-Iminopyridinium ylides give 1,2-dihydropyridine derivatives, which tend to aromatize2 rather (1) Abfamovitch, R. A.; Shinkai, I. Acc. Chem. Res. 1976, 9, 192. Abramovitch, R. A. Lect. Heterocycl. Chem. 1979,5, S-15. Abramovitch, R. A.; Shinkai, I.; van Dahn, R. J. Heterocycl. Chem. 1976, 13, 171. Hisano, T.; Matsuoka, T.; Ichikawa, M.; Muraoka, K.; Komori, T.; Harano, K.; Ida, Y.; Christensen, A. T. Org. Prep. Proc. Int. 1978,10, 300. Hisano, T.; Matsuoka, T.; Ichikawa, M.; Hamana, M. Heterocycles 1980, 14, 19. Abramovitch, R. A,; Kishore, D.; Konieczny, M.; Dauter, 2. Heterocycles, in press. 0022-3263 I861 1951-4739SO1.50 /O I , ,