DYES DERIVED FROM ACENAPHTHENEQUINONE. PART VI. 2-(4-METHYL)-THIONAPHTHENEACENAPHTHYLENE INDIGOS.

A few vat dyes have been prepared by the condensation of 4-methyl-3-hydro y. thionaphthene with acenaphthenequinone and its derivatives. The dyeing shades developed on cotton and on wool from these compounds have been compared with those obtained from 2-thionaphthene-acenaphthylene-indigos and its 5-methy land 6-methyl derivatives. The effect of methyl group in the 4-position of the thionaphthene nucleus of the molecule of the parent compound is to lighten the colour. It has also been:: found that as far as the colour is concerned the 4-methyl compounds occupy an inter­mediate position between the 5-methyl and the 6-methyl derivatives, and the 5-methyl dyes possess the deepest shade. The microphotographs of the spectra of the dyes of the three series have been taken and the absorption maxima determined