Synthesis and biological activity of novel series of 4-methoxy, and 4,9-dimethoxy-5-substituted furo[2,3-g]-1,2,3-benzoxathiazine-7,7-dioxide derivatives

A novel series of 4-methoxy, and 4,9-dimethoxy-5-substituted furo[2,3-g]-1,2,3-benzoxathiazine-7,7-dioxide derivatives 3a,b, 10a–g and 11a–g were prepared in good yields via the reaction of 4-methoxy (1a) and 4,7-dimethoxy-5-acetyl-6-hydroxybenzofurans (1b) and their α,β-unsaturated keto derivatives 6a–g and 7a–g with chlorosulfonyl isocyanate (csi). on the other hand, n-chlorosulfonyl carbamate derivatives 4a,b, 12a,b and 13a,b were prepared and allowed to react with piperidine to give the corresponding n-piperidinosulfonyl carbamate derivatives 5a,b, 14a,b and 15a,b, respectively. sixteen new target compounds 3a,b, 10a–g, and 11a–g were tested for their dpph radical-scavenging, and in vitro antiproliferative activity against a-549, mcf7 and hct-116 cancer cell lines. compounds 10a, 11c, 11e, and 11g showed moderate dpph radical-scavenging activity compared to ascorbic acid at 100 μg/ml. 4,9-dimethoxy-5-substituted styrylfuro[3,2-g]-1,2,3-benzoxathiazine-7,7-dioxides 11a, 11b, and 11c were found to be highly active against a-549 and hct-116 cancer cell lines with ic_50 values ranging from 0.02 to 0.08 μmol/ml compared to doxorubicin with ic_50=0.04 and 0.06 μmol/ml, respectively.