O‐Methylcaprolactim 3 reacts in hot dimethylsulfoxide with α‐amino acids 4 to give 5H‐3‐oxo‐2,3,6,7,8,9‐hexahydroimidazo[1,2‐a]azepines 6 and, unexpectedly, hydroxylated derivatives 7a,c and 8c. The structures of the hydroxylated compounds have been elucidated by spectroscopic means and, when necessary, further confirmed by an independent unequivocal synthesis. The formation of 7 as well as the isomerization of 7c to 8c are discussed in detail.