Chemical reactions of cycloalkanespirohydantoins. Part 3 . Acid‐catalyzed reaction of 4‐hydroxy‐2‐imidazolidinones. Preparation of bis(1,3‐diaza‐2‐oxospiro[4,5]decyl‐4) ether

The use of N ‐carbamoyliminium ion initiated reactions for the generation of spiroimidazolidin‐2‐ones has been successfully exploited. N 3 ‐Substituted‐4‐hydroxy‐2‐imidazolidinones have been treated under acid conditions to give the rearranged imidazolinones. Only in the case of N 3 ‐dialkylaminomethyl‐4‐hydroxy‐5‐cyclohexanespiro‐2‐imidazolidinones upon treatment with trifluoroacetic anhydride/trifluoroacetic acid afforded a mixture containing bis(1,3‐diaza‐2‐oxospiro[4,5]decyl‐4) ether with the rearranged imidazolidinone.