Method for preparing 1,4-diaminoanthraquinones and intermediates thereof

Reference Number: N 03-07

Inventors: Zielske, Alfred G.

USPTO Link: 4746461

Invention Summary

Accordingly, it is an object of the present invention to provide a simple and efficient method for preparing 1,4-diaminoanthraquinones, particularly unsymmetrically substituted 1,4-diaminoanthraquinones.

It is another object of the present invention to provide novel monoamino-monotosyloxy-anthraquinones which are useful as key intermediates in making 1,4-diaminoanthraquinone dyes.

Additional objects, advantages, and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art on examination.

In one aspect of the present invention, a 9,10-anthraquinone is provided having a tesyloxy group and an amino group at the 1- and 4- positions thereof. Such a 9,10-anthraquinone having a tosyloxy and an amino substituent may be readily prepared and isolated in high yield by reacting a 1,4-ditosyloxanthraquinone with an excess of a primary or secondary, aliphatic amine at a mild temperature and in the presence of an organic solvent or by reacting a 1,4-ditosyloxyanthraquinone with an excess of an aromatic amine at an elevated temperature in the presence of an organic solvent.

In another aspect of the present invention, unsymmetrically substituted 1,4-diaminoanthraquinones may be prepared via a monoamino-monotosyloxy-anthraquinone intermediate.