GB492697A - Improvements in or relating to the manufacture of anthraquinone derivatives - Google Patents

Abstract

Aralkylaminoanthraquinones are obtained by reacting a nitro- or amino-anthraquinone, which may carry additional substituents, with an aralkylalcohol at an elevated temperature. Additional substituents specified are halogen, alkyl, hydroxy, alkoxy, nitro or amino groups. The reaction may be effected in an inert solvent such as nitrobenzene or o-dichlorbenzene, and at temperatures ranging from 100 DEG C. to the reflux temperature of the mass or approximately 200 DEG C. When a nitroanthraquinone is used, the presence of alkali is desirable. Monobenzylation of polyaminoanthraquinones may be effected by using an amount of benzyl alcohol only slightly in excess of the theoretical and preferably in a solvent. In examples, the following compounds are reacted with benzyl alcohol: (1) 1.8-diaminoanthraquinone to give 1.8-di-(benzylamino)anthraquinone; (2) 1.4.5.8-tetraaminoanthraquinone to give 1.5-di-(benzylamino) - 4.8 - diaminoanthraquinone (fast blue shades on cellulose acetate); (3) 1.8-diaminoanthraquinone - 4.5 - dihydroxyanthraquinone to give 1.8-di(benzylamino)-4.5-di-hydroxyanthraquinone; (4) 1-amino-2-bromo-4 - toluidoanthraquinone to give 1 - benzylamino - 2 - bromo - 4 - toluidoanthraquinone; (5) 1.8 - dimethoxy - 4.5 - diaminoanthraquinone to give 1.8-dimethoxy-4.5-di(benzylamino))- anthraquinone; (6) 1-nitro-2-methylanthraquinone (in presence of sodium carbonate) to give 1-benzylamino-2-methylanthraquinone (fast orange shades on cellulose acetate); (7) 1 - nitroanthraquinone (with sodium carbonate) to give 1-benzylaminoanthraquinone (red shades); (8) 1.8-diamino-4.5-dihydroxyanthraquinone to give 1-benzylamino-8-amino-4.5 - dihydroxyanthraquinone (reddish blue); (9) 1.8 - dihydroxy - 4.5 - dinitroanthraquinone (with sodium carbonate) to give 1.8-dihydroxy - 4 - benzylamino - 5 - nitroanthraquinone. Also in examples, 1.8 - diamino-4.5 - dihydroxyanthraquinone is reacted with b -phenyl ethyl alcohol to give 1.8-di-(b -phenyl ethylamino) - 4.5 - dihydroxy - anthraquinone. Other alkali metal carbonates or bicarbonates may replace sodium carbonate, and other aralkyl alcohols, such as b -phenyl ethyl alcohol, g -phenyl n-propyl alcohol, or m-nitrobenzyl alcohol may replace benzyl alcohol.