Patent ID: 6365720
Filing Date: 2002-04-02
Classification: C09B,C09D,G03F

Abstract:
A method for preparing a compound of the formula A(D)x(E)y (I) by reaction of a compound of the formula A(H)x(H)y with a pyrocarbonic acid diester of the formula whereinx and y are each independently of the other an integer from 0 to 6, but x and y are not simultaneously the number 0, A is the radical of a chromophore of the quinacridone, anthraquinone, perylene, indigo, quinophthalone, indanthrone, isoindolinone, isoindoline, dioxazine, azo, phthalocyanine or diketopyrrolopyrrole series, which radical is bonded via one or more nitrogen atoms to x groups D and via one or more oxygen atoms to y groups E, the nitrogen atoms and oxygen atoms forming part of the radical A, each group D or E independently of any other(s) is hydrogen or a group of the formula wherein at least one group D or E is not hydrogen, and L is any desired group suitable for solubilization,in the presence of a base as catalyst, in which method the reaction takes place in an aromatic or heteroaromatic solvent selected from diphenyl, pyridine, quinoline, pyrrole and benzene unsubstituted or mono- to tri-substituted by C1-C24alkyl, phenyl, benzyl, C1-C24alkoxy, phenoxy, C1-C24alkylthio, halogen and/or by nitro, and any desired mixtures thereof.