Ethylenediamine → 2-Amino-1,5-naphthalenedisulfonic acid

Beteiligte Stoffe

Reaktionsschritte

31.9 g of 2-amino-5-hydroxy-naphthalene-1,7-disulphonic acid are subjected to a condensation reaction with trifluorotriazine as described in Example 1. 5.0 g of ethylenediamine are added to the solution of the resulting difluorotriazine compound at 0°, a pH of 5.5-6.5 being maintained. The condensation has ended after 2 to 3 hours. A diazo compound obtained by the customary route by diazotisation of 30.3 g of 2-amino-naphthalene-1,5-disulphonic acid is added to the reaction product of the formula ##STR20## which is largely present as a suspension, the pH simultaneously being kept at pH 7.0-7.5 by sprinkling in sodium bicarbonate. When the coupling has ended, the dyestuff of the formula ##STR21## which has precipitated as a sparingly soluble product, is filtered off with suction and stirred in 1 l of water again. 16.9 g of 2,4,6-trifluoro-5-chloro-pyrimidine are added dropwise at 0°-5°, during which a pH of 7.5-8.0 is maintained with dilute sodium hydroxide solution. The dyestuff dissolves during the condensation reaction. When the condensation has ended (thin layer chromatogram), the dyestuff is salted out, filtered off with suction, dried and ground. The red powder dissolves readily in water and dyes cotton a clear scarlet (colour code number 6).

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