| abstract |
PURPOSE: To safely and profitably provide the subject dyestuff useful as a dye, pigment, colorant for filters or recording medium by adding a specific compound to a solution containing a specified compound, a base and a carboxylic acid anhydride at a high temperature. n CONSTITUTION: A compound of formula II (Y - is CH 3 COO - or halogen ion) is added to a solution containing a compound of formula I [R is (substituted) alkyl; X - is arylsulfonate ion, alkylsulfonate ion, alkoxylsulfonate ion or halogen], a base (e.g., sodium acetate) and a carboxylic acid anhydride (preferably acetic anhydride) in a range of 100°C to the refluxing temperature of a solvent to provide a 6,7-benzoindolenine cyanine dyestuff of formula III. n COPYRIGHT: (C)1990,JPO&Japio |