Nitrones and Oxaziridines. XXIX. Synthesis and reactions of 2,3-Diaryl-1-pyrroline 1-oxides

The 2,3-diaryl-1-pyrroline 1-oxides (5) and (6) have been prepared, together with the related pyrrolines (7) and (8). The nitrone (5) undergoes reaction with benzoyl chloride to give the 2H- pyrrole (17) and the pyrroline (18) and nitric acid oxidation of (5) gives the oxo nitrone (21). Both nitrones (5) and (6) react with N -bromosuccinimide to give the 2H-pyrrole 1-oxides (19) and (20) respectively. Ultraviolet irradiation of (5) and (6) give initially the oxaziridines (22) and (23) which undergo ring-contraction to the azetidines (24) and (25), which could not be obtained pure. On attempted purification, compound (25) was converted into the amide (26). The pyrroline (7) was converted in boiling n-hexane into the stable hydroperoxide (9), which was reduced to the hydroxy- pyrroline (15), also derivable from the pyrroline (18).