Bayer Aktiengesellschaft

Karl-Heinz Reinhardt

Dietmar Kalz

Klaus Wunderlich

Stephan Michaelis

Dieter Arlt

Peter Wild

Detlef-Ingo Schutze

Josef-Walter Stawitz

Christoph Thiebes

Reinold Schmitz

Karin Hassenruck

Martin Wienkenhover

Josef Schroder

Helmut Blaser

Reaction of pyrazolones and methyleneindolines with orthoformic esters is an advantageous one-step process for preparing asymmetrical methine dyes.

Process for preparing asymmetrical methine dyes

The present invention relates to a process for preparing compounds of formula (I) ##STR1## wherein A completes an unsubstituted or substituted heteroaromatic ring and

Process for the preparation of quinophthalones

Compounds of the general formula (I) or tautomeric forms thereof ##STR1## wherein Ar.sub.1 and Ar.sub.2 independently of one another denote radicals to complete optionally substituted carbocyclic aromatic rings, B denotes an optionally substituted alkylene group or a radical of the formula ##STR2## wherein r represents a number from 1 to 4, the ends of which are in each case bonded to an aromatic C atom of the two radicals Ar.sub.1 and Ar.sub.2, and

Bridged perinones/quinophthalones

The present invention relates to compounds of the formula (I)

Bridged anthraquinones

The new dyestuffs of the formula (I) ##STR1## wherein the substituents R and R.sup.1 and the index n have the meaning given in the description, are outstandingly suitable for dyeing and printing cellulose-containing materials, in particular for the preparation of recording liquids for ink jet recording systems.

Azodyestuffs, their preparation and their use

A process for the preparation of N,N'-disubstituted 1,4-diaminoanthraquinones has been found which is characterized in that 1,4-dihydroxyanthraquinones are reacted with aliphatic or aromatic amines in the presence of a hydroxycarboxylic acid as a condensation auxiliary.

Process for the preparation of N,N'-disubstituted

Process for the preparation of naphthalene-1,8-dicarboximide which is optionally substituted in the naphthalene ring, characterized in that naphthalene-1,8-dicarboxylic anhydride which is optionally substituted in the naphthalene ring is reacted with an ammonium salt in an aqueous medium at a pH near to the neutral point, the reaction mixture is then acidified to a pH of 1 to 4 and the pH is subsequently adjusted to a value near to the neutral point.

Growing community of inventors

Monheim, Germany

Karl-Heinz Reinhardt