Methods for the synthesis of lactams are presented whereby a carboxylic acid of the formula HOOC------OR---NH-LG, wherein OR is an organic moiety and LG is a leaving group, is reacted with an acid, such as an organic acid, in particular a strong acid, and a dehydrating agent, which may be one in the same such as a strong acid anhydride, such that the amount of acid added allows for the desired transformation to take place without the loss of the leaving group (LG) before the cyclization, and recovering the lactam.
