Yield:6837-97-4 49.5%

Reaction Conditions:

with sulfuryl dichloride in nitrobenzene at 20; for 22 h;Heating / reflux;

Steps:

1 Example 1

Example 1: Synthesis and characterization of anthraquinone fluorophore 1-(6-amino-hexylamino)-5-chloro-4,8-dihydroxy-anthraquinone (KAYA1) 1-(6-amino-hexylamino)-5-chloro-4,8-dihydroxy-anthraquinone (KAYA1) is prepared from commercially available 1,5-Dihydroxy-anthraquinone in a three-step reaction. The starting compound is converted into 1,5-dichloro-4,8-dihydroxy-anthraquinone by treatment with sulfurylchloride in 49.5 % yield after recrystallization according to a procedure described in Allen, C.F.H., Frame, G.F., Wilson, C.V., The Structures Of The So Called Touluidine Blue, Journal of Organic Chemistry, 1941, (6), 732-749. Procedure: 1,5-Dihydroxy-anthraquinone (10 g, 42 mmol) is dissolved in nitrobenzene. After addition of 10 ml SO₂Cl₂ (0.123 mol) the mixture is refluxed for two hours. An additional amount of SO₂Cl₂ (10 ml) was added dropwise and the reaction mixture is refluxed for further 20 hours. The excess SO₂Cl₂ is removed by heating to 210°C. Then the crude 1,5-dichloro-4,8-dihydroxy-anthraquinone is filtered and washed first with methanol and then with ether. The red compound is recrystallized from anisole.

References:

EP1905801,2008,A1 Location in patent:Page/Page column 7,8