Abstract
The reaction of 3-alkylindoles (1) with sulfur monochloride in ether gave the corresponding 2-diindolyl disulfides (2) as the main product, and mono and tri-sulfides (3) as minor products. The similar reaction of 3-arylindoles (6) gave the disulfides (7) in good yields. 2-Chloro derivatives (4 and 9) were obtained as the minor products in the reaction of 1e and 6d. The reactions of 1e, 6g and 6h with sulfur monochloride in ether were very slow, but proceeded rapidly in methylene chloride. The reduction of these diindolyl disulfides (11) with sodium borohydride in ethanol afforded the 2-indolinethiones (12) in good yields. These reactions are a general method for the preparation of 3-substituted 2-indolinethiones from 3-substituted indoles.
