CI Pigment Yellow 65, α-(4-methoxy-2-nitrophenylhydrazono)-α-aceto-2'-methoxyacetanilide

Whitaker, Α.

doi:10.1107/s0108270187088711

Cited by 10 publications

(2 citation statements)

References 7 publications

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“…Orange food coloring tartrazine is an azopyrazole which is known to be resistant to azoreduction both in vivo and in vitro . It is postulated that this resistance is due to its existence solely as the (5-oxo-pyrazol-4-ylidene)hydrazine tautomer, which is not recognized by the reductase enzymes. − Therefore, replacement of the lower naphthol ring of our diazonaphthol compounds with various pyrazolin-5-ones was undertaken (Figure ) in the hope that potency would be retained and the potential for azoreduction eliminated. Fortunately, the pyrazolinone was an effective replacement for the naphthol group with activity retained albeit at somewhat reduced potency (Table ).…”

Section: Resultsmentioning

confidence: 99%

Hydrazinonaphthalene and Azonaphthalene Thrombopoietin Mimics Are Nonpeptidyl Promoters of Megakaryocytopoiesis

et al. 2001

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High-throughput screening for the induction of a luciferase reporter gene in a thrombopoietin (TPO)-responsive cell line resulted in the identification of 4-diazo-3-hydroxy-1-naphthalenesulfonic acids as TPO mimics. Modification of the core structure and adjustment of unwanted functionality resulted in the development of (5-oxo-1,5-dihydropyrazol-4-ylidene)hydrazines which exhibited efficacies equivalent to those of TPO in several cell-based assays designed to measure thrombopoietic activity. Furthermore, these compounds elicited biochemical responses in TPO-receptor-expressing cells similar to those in TPO itself, including kinase activation and protein phosphorylation. Potencies for the best compounds were high for such low molecular weight compounds (MW < 500) with EC(50) values in the region of 1-20 nM.

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Section: Resultsmentioning

confidence: 99%

Hydrazinonaphthalene and Azonaphthalene Thrombopoietin Mimics Are Nonpeptidyl Promoters of Megakaryocytopoiesis

et al. 2001

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“…Whereas in solution both tautomers are populated, in the solid state, all yellow azo pigments exist as the hydrazo tautomer because the acetoacetyl substituents form intramolecular hydrogen bonds between the acetyl and the hydrazo groups. This has been shown by single-crystal analyses of many mono-azo pigments of the Hansa Yellow type. , (Monoazo pigments are much more soluble than diazo pigments; therefore, single crystals of sufficient size and quality can be grown.)…”

Section: Methodsmentioning

confidence: 97%

Crystal Engineering on Industrial Diaryl Pigments Using Lattice Energy Minimizations and X-ray Powder Diffraction

2007

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Diaryl azo pigments play an important role as yellow pigments for printing inks, with an annual pigment production of more than 50,000 t. The crystal structures of Pigment Yellow 12 (PY12), Pigment Yellow 13 (PY13), Pigment Yellow 14 (PY14), and Pigment Yellow 83 (PY83) were determined from X-ray powder data using lattice energy minimizations and subsequent Rietveld refinements. Details of the lattice energy minimization procedure and of the development of a torsion potential for the biphenyl fragment are given. The Rietveld refinements were carried out using rigid bodies, or constraints. It was also possible to refine all atomic positions individually without any constraint or restraint, even for PY12 having 44 independent non-hydrogen atoms per asymmetric unit. For PY14 (23 independent non-hydrogen atoms), additionally all atomic isotropic temperature factors could be refined individually. PY12 crystallized in a herringbone arrangement with twisted biaryl fragments. PY13 and PY14 formed a layer structure of planar molecules. PY83 showed a herringbone structure with planar molecules. According to quantum mechanical calculations, the twisting of the biaryl fragment results in a lower color strength of the pigments, whereas changes in the substitution pattern have almost no influence on the color strength of a single molecule. Hence, the experimentally observed lower color strength of PY12 in comparison with that of PY13 and PY83 can be explained as a pure packing effect. Further lattice energy calculations explained that the four investigated pigments crystallize in three different structures because these structures are the energetically most favorable ones for each compound. For example, for PY13, PY14, or PY83, a PY12-analogous crystal structure would lead to considerably poorer lattice energies and lower densities. In contrast, lattice energy calculations revealed that PY12 could adopt a PY13-type structure with only slightly poorer energy. This structure was found experimentally as a metastable gamma phase of PY12. Calculations on mixed crystals (solid solutions) showed that mixed crystals of PY12 and PY13 should adopt the PY13 structure with planar molecules, resulting in high color strengths; this was proven experimentally (Pigment Yellow 188). Similarly, the high color strength of mixed crystals consisting of PY13 and PY14 (Pigment Yellow 174), and PY13/PY83 (Pigment Yellow 176) is explained by the crystal structures.

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Hydrazone Pigments (Formerly Called Azo Pigments)

2018

Industrial Organic Pigments

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CI Pigment Yellow 65, α-(4-methoxy-2-nitrophenylhydrazono)-α-aceto-2'-methoxyacetanilide

Abstract: Abstract. 2-[ (4-Methoxy

Cited by 10 publications

References 7 publications

Hydrazinonaphthalene and Azonaphthalene Thrombopoietin Mimics Are Nonpeptidyl Promoters of Megakaryocytopoiesis

Hydrazinonaphthalene and Azonaphthalene Thrombopoietin Mimics Are Nonpeptidyl Promoters of Megakaryocytopoiesis

Crystal Engineering on Industrial Diaryl Pigments Using Lattice Energy Minimizations and X-ray Powder Diffraction

Hydrazone Pigments (Formerly Called Azo Pigments)

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