Nitrones and Oxaziridines. XLII. Synthesis of Indol-3-yl-Substituted 1-Pyrroline 1-Oxides

The 1-pyrroline 1-oxides (13), (14), (16) and (18) with indol-3-yl substituents attached to the 2- or 4-positions have been synthesized by reductive cyclization of the related ?-nitro ketones. The corresponding 1-pyrrolines (15), (17) and (19) have also been isolated as the result of non-selective reduction. The 1-pyrroline 1-oxides cannot be converted into the related 2 H -pyrroles, nor can they be oxidized by nitric acid to a- hydroxy ketones , as can simpler 2,4-diaryl-1-pyrroline 1-oxides.