Process for the preparation of azo dyes
AssigneeCiba-Geigy Corporation
InventorRobert Portmann
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Abstract
The invention relates to a process for the preparation of azo dyes of the formula ##STR1## or mixtures thereof, in which Ar is a substituted or unsubstituted phenyl, naphthyl or aromatic heterocyclic radical and Y is a group of the formula --O-R, --S-R or ##STR2## in which R is a substituted or unsubstituted alkyl, aryl or heterocyclic radical and R.sub.1 and R.sub.2 independently of one another are hydrogen or a substituted or unsubstituted alkyl, aryl or heterocyclic radical, and the groups R.sub.1 and R.sub.2, together with the nitrogen atom to which they are bonded, can form a ring. The process comprises first coupling dimeric malonodinitrile with a diazo component and cyclizing the resulting intermediate with an alcohol, thioalcohol or amine.
Claims13
A process for the preparation of an azo dye of the formula ##STR52## or of a mixture thereof, in which Ar is a substituted or unsubstituted phenyl, naphthyl or aromatic heterocyclic radical and Y is a group of the formula --O--R, --S--R or ##STR53## in which R is a substituted or unsubstituted alkyl, aryl or heterocyclic radical and R.sub.1 and R.sub.2 independently of one another are hydrogen or a substituted or unsubstituted alkyl, aryl or heterocyclic radical, and the groups R.sub.1 and R.sub.2, together with the nitrogen atom to which they are bonded, can form a ring, which comprises coupling a diazonium salt of the formula
- Ar N.sub.2.sup..sym. X.sup..crclbar.
- in which Ar is as defined above and X.sup..crclbar. is an anion, with dimeric malonodinitrile to give an intermediate of the formula ##STR54## in which Ar is as defined above, and cyclising this intermediate with an alcohol or thioalcohol of the formula ROH or RSH or an amine of the formula ##STR55## in which formulae R, R.sub.1 and R.sub.2 are as defined above, it being necessary for the amine to be present in the form of the ammonium salt during the reaction.
A process for the preparation of a compound of the formula ##STR57## in which Ar is a substituted or unsubstituted phenyl, naphthyl or aromatic heterocyclic radical, which comprises coupling a diazonium salt of the formula
- Ar N.sub.2.sup..sym. X.sup..crclbar.
- in which Ar is as defined above and X.sup..crclbar. is an anion, with dimeric malonodinitrile.
Dependencies are inferred from the claim text.