Synthesis and antinociceptive activity of some 3-substituted benzothiazolone derivatives

Thirteen 3-substituted benzothiazolone derivatives have been synthesized. Their chemical structures have been elucidated by IR and NMR spectral data and by elemental analyses. Among these compounds, 1-{3-[2(3 H)-benzothiazolon-3-yl]propanoyl}morpholine ( 5b); 1-{3-[2(3 H)-benzothiazolon-3-yl]propanoyl}-4-benzylpiperidine ( 5c); 1-{3-[2(3 H)-benzothiazolon-3-yl]propanoyl}-4-phenylpiperazine ( 5d); 3-[3-(4-benzylpiperidine-1-yl)propyl]-2(3 H)-benzothiazolone ( 5k); 3-[3-(4-benzylpiperazine-1-yl)propyl]-2(3 H)-benzothiazolone ( 5l); 3-[3-(4-phenylpiperazine-1-yl)propyl]-2(3 H)-benzothiazolone ( 5m) have been found to be significantly more active than the others.