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Short Paper | Regular issue | Vol 98, No. 5, 2019, pp.693-702
Published online, 11th April, 2019
DOI: 10.3987/COM-19-14065
An Efficient Two-Step Synthesis of 3-Aroyl-2,3-dihydro-1,4,2-benzodithiazine 1,1-Dioxides from Secondary Benzenesulfonamides, Sulfur, and Phenacyl Bromides

Kazuhiro Kobayashi* and Daiki Fujiwara

*Applied Chemistry Field, Chemistry and Biotechnology Course, Department of Engineering, Graduate School of Sustainability Science, Tottori University, 4-101 Koyama-minami, Tottori 680-8552, Japan


An efficient method for the synthesis of 2-substituted 3-aroyl-2,3-dihydro-1,4,2-benzodithiazine 1,1-dioxides has been developed. Thus, 2,N-dilithio compounds of secondary benzenesulfonamides, generated by treating secondary benzenesulfonamides with two equivalents of butyllithium, are allowed to react with elemental sulfur and then phenacyl bromide and its derivatives to give N-substituted o-[(aroylmethyl)sulfanyl]benzenesulfonamides in moderate to good yields. Oxidative coupling of these precursors to the desired products can be achieved in moderate to good yields on successive treatment with sodium hydride and iodine under mild conditions.