Efficient synthesis of azetidine through N-trityl- or N- dimethoxytritylazetidines starting from 3-amino-1-propanol or 3- halopropylamine hydrohalides

Article abstract of DOI:10.1002/jhet.5570300506

Efficient synthetic routes for the preparation of azetidine starting from commercially available 3-amino-1-propanol or 3-halopropylamine hydrohalides are reported. First, the appropriate N-trityl- or N-dimethoxytrityl protected tosyloxy- or halopropylamines were prepared. These precursors were then cyclized into the N-trityl- or N-dimethoxytritylazetidines. The N-protecting groups were removed in the presence of perchloric acid giving the hydrogen perchlorate salt of azetidine. The latter compound was transformed into its free base using a strong base under anhydrous conditions. The relatively expensive 4,4'-dimethoxytrityl chloride and less expensive trityl chloride used in these synthetic procedures were recycled in good yields. Azetidine hydrogenperchlorate can be used to prepare N-substituted azetidines without the need to isolate the free azetidine.