Synthesis and anti-inflammatory evaluation of novel angularly or linearly fused coumarins

Angular [7,8]-fused coumarins were obtained from the reaction of [2,3]-fused phenols with DMAD and PPh(3), while linear [6,7]-fused coumarins were formed from the analogous reaction of [3,4]-fused phenols with DMAD and PPh(3). These compounds were tested in vitro for antioxidant activity and they found to present significant scavenging activity. In parallel, these new compounds were evaluated in vivo for anti-inflammatory activity and they found to inhibit the carrageenin-induced paw edema (34-65%). Although their interaction with the free stable radical DPPH was low, the methyl 2,2-dimethyl-8-oxo-3,8-dihydro-2H-furo[2,3-h]chromene-6-carboxylate was the most potent (65%) in the in vivo experiment. The later seems to be a potent soybean Lipoxygenase inhibitor and does not acquire gastrointestinal toxicity.