Imrecoxib

Imrecoxib, a new non-steroid anti-inflammtory drug (NSAID), was launched in China with the trade name of Hengyang® for the treatment of osteoarthritis in 2012. It was originally designed and synthesized by Guo and co-workers at the Institute of Materia Medica (IMM) of the Chinese Academy of Medical Sciences in collaboration with Hengrui Pharmaceuticals. Imrecoxib, which is a moderately selective COX-2 inhibitor (with IC50 values against COX-1 and COX-2 being 115 ± 28 nM and 18 4 nM, respectively).

Imrecoxib has had two synthetic routes reported across several publications. The most likely process-scale route to this drug is described in the scheme, which began with 2-bromo-4'-(methylsulfonyl)-acetophenone (84) and p-tolylacetic acid (85) as starting materials. In the presence of base, |á-bromoketone 84 was treated with acid 85 which resulted in lactone 86 in 72% yield across the two-step sequence. Exposure of lactone 86 with propylamine triggered a ring-opening-ring closing reaction, which resulted in imrecoxib (XIII) directly in 85% yield.