Process for Synthesis of Lactams

摘要

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 such as that of the formula (a), provided herein, wherein G represents the atom(s) needed to form a closed ring.

主权项

1. A process for making a 4-8 membered lactam ring of the formula (a) wherein G represents 1-5 atoms to complete said ring wherein, reading from left to right, G represents: —C— for a 4-membered ring and —C—C—, —C—O—, —O—C—, —N—C, —C—N— for a 5-membered ring and C, O, or N, for 6, 7 and 8-membered rings wherein any open valences are H or an organic moiety or wherein open valences represent a ring bonded to adjacent atoms or the same atom as allowed by valence, the process comprising the steps of (i) treating a carboxylic acid of formula (b) with an acid and a dehydrating agent wherein LG is a leaving group such that the amount of acid added allows for the desired transformation to take place without the loss of the leaving group (LG) before cyclization, and (ii) recovering the lactam (a).