Compounds with Bridgehead Nitrogen. 42 - 1H NMR and Stereochemistry of Isomeric 6a-Methylperhydroindolobenzoxazines and the Position of Conformational Equilibrium in Perhydropyrrolooxazine

Article abstract of DOI:10.1002/mrc.1270200209

The 1H NMR parameters of the NCH2O protons in the spectrum of perhydropyrrolo<1,2-c><1,3>oxazine show its existence in solution at room temperature in the O-inside cis-fused conformation, rel-(3aS,6aS,6bR,10aS,11aS)6a-Methylperhydroindolo<3,2,1-i,j>benzoxazine and rel-(3aS,6aS,6bS,10aR,11aS)-6a-methylperhydroindolo<3,2,1-i,j>benzoxazine are shohn to adopt cis- and trans-fused conformations, respectively, for the corresponding bicyclic moiety.