Chemistry of the indoleninones. I. Derivatives of 2-chloroindoleninone (α-chloroisatin) on reaction with methanethiol, benzenethiol, and 1,2-ethanedithiol

The reactive 2-chloroindoleninone has been used to prepare a series of 2,2-and 3,3-dialkylthio- and diarylthio-indolinones, 2-phenylthioindoleninone, and 2-methylthioindoleninone, the last named being a debromo analogue of a product of hydrolysis and dehydrogenation of 6-bromo-2-methylthioindoxyl sulphate, an absolute precursor to the major constituent of the dye Tyrian Purple.