2,5-diphenyl-3-morpholinofuran and its 2-hydro, 2-bromo and 2-hydroxymorpholinofurylium salts

2,5-Diphenyl-3-morpholinofuran ( 1 ) reacts with bromine and trifluoroacetic acid, giving respectively 2-bromo and 2-hydro furylium salts ( 2,3 ). The 2-hydroxy furylium bromide ( 4 ) was obtained by reaction of cis-morpholino-1,2-dibenzoylethylene ( 5 ) with hydrogen bromide. The nmr spectra of these salts show differences between the two morpholino dimethylene moieties of each caused by restricted rotation at the 3-immonium group. Chemical relationships studied include reductions to the morpholinofuran, conversions to 3-furanones, and the slow reaction of morpholinodibenzoylethylene with phenylmagnesium bromide to give cis-dibenzoylstyrene (13).