Reaction of four‐membered cyclic nitrones with acetyl chlorideα. X‐Ray crystal structures of 2‐[(acetyloxy)amino]‐N,N‐diethyl‐2‐methyl‐4‐oxo‐3‐phenylpentanamide and 1‐acetyl‐3‐chloro‐N, N‐diethyl‐2‐methyl‐4‐methylene‐3‐phenyl‐2‐azetidinecarboxamide

Reactions of the four-membered cyclic nitrones 1 with acetyl chloride differ strongly from those of other (cyclic) nitrones. In the presence of water, the nitrones 1 yield the 2-[(acetyloxy)-amino]-N,N-diethylalkanamides 4. The structure of 4b was confirmed by X-ray analysis. In the absence of water, the N,N-diethyl-4-methylene-2-azetidinecarboxamides 5 or the N,N-diethyl-2,3-dihydro-2-azetecarboxamides 6 were obtained. X-ray analysis elucidated the structure of 5a. Under acidic conditions, compounds 5a yielded the 2-oxa-5-azabicyclo[2.1.1]hexan-3-one derivative 13. Acid hydrolysis of 6a gave the α-chloroketone derivative 18 and the 2-oxopropanamide derivative 19.