Preparation and In Vivo Antinociceptive Behavior of Four New 2-Amino-6-trifuromethoxybenzothiazole Carboxylic Acid Derivatives

Four novel N-substituted riluzole derivatives (4 a-4 d) have been prepared and characterized. Their antinociceptive activities have been carefully investigated by hot-plate test and writhing test. Our results indicated that at dose of 18 mg kg⁻¹, 2-(N-propionic acid)-6-trifluoromethoxy-benzothiazole (4 a), 2-(N-butanoic acid)-6-trifluoromethoxy-benzothiazole (4 b) and 2-(N-n-caproic acid)-6-trifluoromethoxy-benzothiazole (4 c) significantly increased the nociceptive response latency under hot plate test while chemical nociception induced by intraperitoneal acetic acid was significantly inhibited by 4 a and 2-(N-proline)-6-trifluoromethoxy-benzothiazole (4 d) at same dosage. Our research clearly indicates that N-substituted Riluzole derivatives could be new alternative candidates as potential antinociceptive medicines.