Synthesis of benzothiazoles through copper-catalyzed one-pot three-component reactions with use of sodium hydrosulfide as a sulfur surrogate

Copper-catalyzed one-pot three-component reactions of 2-iodoanilines, aldehydes, and NaSH·n H ₂O afford benzothiazoles in good yields. When CuCl was employed as a catalyst in the absence of a ligand, a variety of aromatic aldehydes and substituted 2-iodoanilines reacted with NaSH·n H ₂O to produce the corresponding 2-arylbenzothiazoles in 70-98 % yields. The copper catalyst plays a key role in C-S bond formation between NaSH·n H ₂O and the aryl iodide that was formed from the condensation of 2-iodoaniline and aldehyde. It was found that NaSH·n H ₂O functions as a sulfur surrogate and oxidant in the formation of benzothiazole. 2-Iodoanilines, aldehydes, and NaSH·n H ₂O afford benzothiazoles in a one-pot reaction in the presence of a copper catalyst. The desired products can be obtainedin moderate to good yields. The copper catalyst plays a key role in C-S bond formation between aryl iodides and NaSH·n H ₂O.