Electrochemical synthesis for benzisothiazol-3(2H)-ones by dehydrogenative N S bond formation

Electro-organic synthesis: an environmentally benign alternative for heterocycle synthesis

“…Zhong et al 132 reported the transition metal catalyst and external oxidant-free synthesis of benzisothiazole-3(2 H )-one ( 166 ) via intramolecular S–N bond formation. The reaction conditions were optimised using 2-mercapto- N -phenyl-benzamide ( 165a ) as substrate.…”

Advances in S–N bond formation via electrochemistry: a green route utilizing diverse sulfur and nitrogen sources

“…107,108 In 2021, an electrochemical method for the synthesis of benzisothiazol-3(2H)-ones 56 from 2-mercapto benzamides 55 via dehydrogenative S-H/N-H bond formation was reported by Chen and co-workers (Scheme 30). 109 The reaction employed 2-mercapto-N-substituted-amine-benzamide as the substrate from the reaction of methyl thiosalicylate with the amine in the presence of AlMe 3 . The reaction was performed in a dichloromethane solution containing n Bu 4 NBr under constant-current electrolysis in an undivided cell equipped with a graphite rod anode and platinum plate cathode.…”

Chemodivergent Synthesis of Benzothiadiazin-3-one 1-Oxides and Benzisothiazol-3-ones via Visible Light-Promoted Intramolecular N–S Bond Formation

“…To better understand the reaction, control experiments were conducted to clarify the roles of CBr 4 and O 2 in the reaction mechanism. First, we used 5 as the substrate, which was prepared according to the reported method; 19 the desired product 2a was afforded in comparable yield with or without CBr 4 (Scheme 3b). It means that CBr 4 did not participate in the oxidation of 5 to 2a and this transformation possibly proceeded via a stepwise two-step reaction rather than a concerted process.…”

“…2-Phenylbenzo [d]isothiazol-3(2H)-one (4a). 19 The reaction was performed following the general procedure, and the product was obtained after flash column chromatography on silica gel with ethyl acetate/petroleum ether (1:3 vol) as eluents. Yield: 37.7 mg, 83%, white solid; 1 H NMR (400 MHz, CDCl 3 ); δ 8.10 (d, J = 8.0 Hz, 1H), 7.73− 7.68 (m, 2 H), 7.66 (t, J = 7.6 Hz, 2H), 7.58 (d, J = 8.0 Hz, 1H), 7.50− 7.41 (m, 3H), 7.32 (t, J = 7.6 Hz, 1H); 13 C { 1 H} NMR (100 MHz, CDCl 3 ): δ 164.2, 139.9, 132.4, 129.4, 127.2, 127.1, 125.8, 124.9, 124.6, 120.1.…”