Synthesis and biological evaluation of novel 1,5-benzothiazepin-4 (5h)-ones as potent antiangiogenic and antioxidant agents

Novel 1,5-benzothiazepin-4-(5H)-one derivatives (8a-8g) have been synthesized by intramolecular cyclization of 6 using propyl phosphonic anhydride (T3P) as a cyclodehydrating agent. The anti-angiogenic and anti-oxidant properties of the new derivatives were then evaluated. Compounds 8b, 8d, 8e, 8f and 8g exhibited very good inhibition of capillary proliferation, thus proving their anti-angiogenic properties. In addition, the in vitro antioxidant activities of these compounds were evaluated using diphenyl picryl hydrazine (DPPH), OH-, metal ion-chelating and NO (nitric oxide) assays, and the results compared with butylated hydroxytoluene (BHT), a well known anti-oxidant. Compounds 8a-8g showed excellent free-radical scavenging activities in the metal ion-chelating assay, and compounds 8f and 8g showed nitric oxide radical scavenging properties at a concentration of 20-100 µg/mL, and are thus more potent than BHT