Pyrazole Orange

Pyrazolone derivatives have found many applications as cotton azo dyes because, even if they were more expensive intermediates, they improved qualities such as brightness and light fastness. Rosanthrene Orange (727) and Pyrazol Orange (728) are two representative examples. 

Pyrazoles, 13 599 Pyrazolinone couplers, 19 254-255 Pyrazolo-(3,2,-c)-5-triazole couplers, 19 256 Pyrazolobenzimidazole couplers, 19 256 Pyrazolone dyes, 19 285 Pyrazolone Orange, 19 435 pigment for plastics, 7 367t Pyrazolone reds, 19 437 Pyrazolones, 9 283 13 599... 

The structures of 123-126 were based on spectroscopic data, on combustion analyses, and chemical evidence. Compounds 124a-c showed a characteristic orange color attributed to the local push-pull system of conjugated double bonds and lone pairs. Compounds 125a-c showed a characteristic red color. The results of combustion analysis and spectroscopic data suggested the presence of 3-amino-17/-pyrazole-4,5-dicarbonitrile 126 as a precipitate from the reaction between 121c and 122. The structure of 126 was confirmed by comparison with authentic sample. 

Tartrazine occurs as a yellow-orange powder or granules. It is principally the trisodium salt of 4,5-dihydro-5-oxo-l-(4-sulfophenyl) -4-(4- sulfophenyl- azo) - IH-pyrazole- 3- carboxylic acid. When dissolved in water, it yields a solution golden yellow at neutrality and in acid. When dissolved in concentrated sulfuric acid, it yields an orange-yellow solution that turns yellow when diluted with water. It is insoluble in ethanol. 

CAS 10127-27-2 El NECS/ELINCS 233-357-8 Synonyms Chromate(l-), [3-[(4,5-dihydro-3-methyl-5-oxo-1-phenyl-1 H-pyrazol-4-yl) azo]-2-hydroxy-5-nitrobenzenesulfonato (3-)] hydroxy-, sodium Cl 18745 Solvent orange 5 Classification Chromium complex azobenzene... 

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