An access to new N- pyrrolylcarboxylic acids as potential COX-2 inhibitors via Paal- Knorr cyclization

Twenty new N- pyrrolylcarboxylic acids were designed to assume the architecture of contemporary selective COX- 2 inhibitors as potential anti- inflammatory agents. The targeted products were synthesized in 70- 82% yields by Paal- Knorr cyclization of a set of eight amino acids, acting as primary amines, and four 1,4- dicarbonyl compounds. The latter substrates were prepared by C- alkylation of three commercially available B- dicarbonyl compounds with two.- bromoacetophenones and used in situ. These compounds inhibit carrageenin- induced rat paw edema and show analgesic activity.