Herwig Fischer-Colbrie

Farbstoffe durch Amin—HCN-Austauschreaktion am 2-Dicyanmethylen-1,3-indandion, 2. Mitt.

Further examples for the amine—HCN-exchange reaction of dieyanomethylene-1.3-indandione are given. With aminonaphthoquinones and aminoanthraquinones, resp., thermolabile adducts are isolated, which eliminate HCN to anthrachinoyl-amino-dioxo-indanyliden-acetonitriles and dioxo-indanylidene-naphthochinoyl-amino-acetonitriles, resp. The reaction of dicyanomethylene-1.3-indandione with amino-pyrazoles yields indeno-pyrazolo-pyridines, formed by elimination of HCN and condensation. In the presence of piperidine or morpholine malononitrile is added to dicyanomethylene-indandione and orange-red amino-dioxo-indanylidene-piperidino- (morpholino-) propene-dicarbonitriles are formed.

Synthesen mit Nitrilen, XLVIII Merocyanine und Oxonole von Phenyl-indanyliden-acetonitrilen / Syntheses with Nitriles, XLVIII Merocyanines and Oxonoles of Phenyl-indanylidene-acetonitriles

2-Dicyanomethylene-1,3-indandione reacts with 2,6-disubstituted anilines to give aminophenyl-1,3-dioxo-2-indanyl-malononitriles. By heating or by photolysis HCN is eliminated from the adducts and deeply coloured aminophenyl-1,3-dioxo-2-indanylideneacetonitriles are formed. They are classified as merocyanine type polymethines. The irreversible change in colour occurs at temperatures above 70 °C, the adducts are therefore capable of indicating temperatures. Reaction of phenols with 2-dicyanomethylene-1,3-indandione yields hydroxyphenyl-1,3-dioxo-2-indanylideneacetonitriles, oxonole type polymethines with the properties of pH-indicators.