3.87 g of 1-amino-3-imino-isoindolenine and 1.95 g of bis-cyanoacetylethylenediamine are heated in 50 ml of water for 2 hours to reflux temperature. Then 2.56 g of barbituric acid and 20 ml of acetic acid are added and the mixture is refluxed for a further 5 hours. The pigment is collected hot with suction and washed with water and dried, affording 5.1 g of a yellow colourant powder. When incorporated in lacquers without further treatment, this pigment produces brilliant, strong colourations of outstanding fastness to overstripe bleeding. For incorporation in printing inks or plastics, the pigment is advantageously brought into the form of a preparation. This is accomplished by known methods by coating the finely dispersed pigment with substrate-compatible resins. When the pigment is used in printing, brilliant yellow colourations of excellent lightfastness are obtained. The bis-cyanoacetylethylenediamine (m.p. 191° C.) is obtained by conventional methods by reaction of ethylenediamine with ethyl cyanoacetate.
