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

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Reaction Steps

31.9 g of 2-amino-5-hydroxynaphthalene-1,7-disulphonic acid are condensed with trifluorotriazine by the procedure of Example 1.5.0 g of ethylenediamine is added to the solution of the resulting difluorotriazine compound at 0° while maintaining a pH of 5.5 to 6.5. After 2 to 3 hours, condensation is complete. A diazo compound obtained in the usual manner by diazotisation of 30.3 g of 2-aminonaphthalene-1,5-disulphonic acid is added to the reaction product of the formula ##STR18## which is largely present as a suspension, while simultaneously maintaining the pH at 7.0 to 7.5 by sprinkling in sodium bicarbonate. After coupling is complete, the dyestuff of the formula ##STR19## which has precipitated as a sparingly soluble compound, is filtered off with suction and stirred again in 1 l of water. 16.9 g of 2,4,6-trifluoro-5-chloropyrimidine are added dropwise at 0° to 5° while maintaining a pH of 7.5 to 8.0 with dilute sodium hydroxide solution. During condensation, the dyestuff goes into solution. After condensation is complete (thin-layer chromatogram), the dyestuff is salted out, filtered off with suction, dried and milled. The orange-coloured powder is readily soluble in water and dyes cotton in clear orange shades (colour indicator number 5).

Provenance & Evidence