STUDIES IN INDIGOID DYES. PART XI. PHENANTHRATHIOPHENE-INDIGOS

9-Thiolphenanthreue and some of its derivatives have been synthesised by the author with a view to preparing some interesting dyes from the point of view of colour in relation to chemical constitution. Some of these dyes have already been described in pars X of this series. The present communication deals with the prepration of bis-9 : 10-phenanthrathiophene-indigo starting from 9-thiolphenanthrene through 9 : 10-phenantbxa-2'-ketodihydrothiophene. It is a dark chocolate dye and dyes cotton in brown shade and this result is in conformity with the previous findings of the author.