Synthesis and cytotoxicity of novel N-sulfonyl-1,2,3,4- tetrahydroisoquinoline thiosemicarbazone derivatives

Abstract

The modified Pictet-Spengler reaction of phenylethylbenzene sulfonamide with a commercially available glyoxal to construct 1-benzoyl- and 1-acetyl-1,2,3,4-tetrahydroisoquinolines 9a-n has been reported. The reaction could be accomplished, regardless of the oxygenation pattern on the aromatic ring, leading to the N-sulfonyltetrahydroisoquinoline analogs which are versatile intermediates for the synthesis of new thiosemicarbazone analogs of 1,2,3,4-tetrahydroisoquinoline. Bioactivity test revealed that most thiosemicarbazones displayed cytotoxic potency against MOLT-3 cell lines with an IC50 less than 20 μg/mL. Significantly, the thiosemicarbazone analog of 1-acetyltetrahydroisoquinoline 9j was the most potent cytotoxic compound against HuCCA-1, HepG2, and MOLT-3 cells. This study provides the novel lead molecules for further development. © 2012 Springer Science+Business Media, LLC.