Goldgelbe bis rotgelbe kationische Farbstoffe und Verfahren zur Herstellung derselben

摘要

1,237,160. Quinoxaline; tetrahydroquinoxaline. E. I. DU PONT DE NEMOURS & CO. 24 Oct., 1969 [7 Nov., 1968], No. 52251/69. Heading C2C. [Also in Division C4] 40% Aqueous glyoxal is added slowly at 55- 60‹ C. to an aqueous mixture of NaOH and ophenylenediamine to form quinoxaline which is hydrogenated in situ at 100‹ C., after adding Ni/catalyst and xylene, to give 1,2,3,4-tetrahydroquinoxaline.