93449-60-6

Upstream product

• 40339-35-3 sudan I 
• 62-53-3 aniline 
• 135-19-3 β-naphthol 
• 619-97-6 benzenediazonium nitrate 
• 842-07-9 Sudan I 

Downstream Products

• 15242-79-2 bis-1-(phenyl-azo)-2-naphtholatecopper(II) 
• 40339-35-3 sudan I 

Relevant academic research and scientific papers

The remarkable hyperchromicity of ketohydrazone dyes and pigment lakes derived from 4-morpholino-2-naphthol

The syntheses of a series of new ketohydrazone dyes and pigment lakes with a unique structural motif derived from 4-morpholino-2-naphthol are described. The morpholine substituent is responsible for the hypsochromically shifted absorption maxima with significantly enhanced molar extinction coefficients of the new dyes; this conclusion is supported by time-dependent DFT (TD-DFT) simulations. The location of the morpholine substituent at a sterically demanding site in the pigment lake obstructs further coordination of the bridging sulfonate groups in the solid state and prevents the formation of a 1-dimensional polymeric system, which is common for other pigment lakes. A new series of ketohydrazone dyes and pigment lakes with a unique structural motif derived from 4-morpholino-2-naphthol are described. The morpholine substituent is responsible for the enhanced molar extinction coefficients of the new dyes. The crystal structure of the pigment lake reveals the absence of bridging sulfonate groups, which prevents the formation of a 1-dimensional polymeric system. Copyright

A new nitrite ionic liquid (IL-ONO) as a nitrosonium source for the efficient diazotization of aniline derivatives and in-situ synthesis of azo dyes

A new task-specific nitrite containing ionic liquid derived from the O-nitrosation of N-methyl-N-hydroxybutylimidazolinium chloride was synthesized and used as a source of nitrosonium ion to affect the efficient diazotization of arylamines. The diazonium salts thus obtained were coupled, using standard experimental procedures, to a range of tertiary anilines, phenols and naphthols to afford the requisite azo dyes in good yield. The diazotization and subsequent azo-coupling generated the related azo dyes at 0-5 °C in short reaction times with a simple experimental procedure.

Substituent and solvent effects on the proton transfer equilibrium in anils and azo derivatives of naphthol. Multinuclear NMR study and theoretical calculations

The tautomeric equilibrium due to proton transfer is compared in a series of anils of 2-hydroxynaphthalene-1-carbaldehyde and azo derivatives of 2-naphthol. Although structurally similar, these systems suffer different substituent effects on the solution-state proton transfer properties. The comparative study was performed using 1H, 13C and 15N NMR spectroscopy in a variety of solvents. Hartree-Fock ab initio calculations involving relative stability of tautomers and full geometry optimization for the ground state are in agreement with the experimental observations.

Waste-free chemistry of diazonium salts and benign separation of coupling products in solid salt reactions

Gas-solid and solid-solid techniques allow for waste-free and quantitative syntheses in the chemistry of diazonium salts. Five techniques for diazotations with the reactive gases NO2, NO and NOCl are studied. Two types are mechanistically investigated with atomic force microscopy (AFM) and are interpreted on the basis of known crystal packings. The same principles apply to the cascade reactions that had been derived from one-step reactions. Solid diazonium salts couple quantitatively with solid diphenylamine and anilines to give the triazenes. Azo couplings are achieved with quantitative yields by cautious co-grinding of solid diazonium salts with β-naphthol and C-H acidic heterocycles, such as barbituric acids or pyrazolinones. Solid diazonium salts may be more easily applied in a stoichiometric ratio for couplings in solution. Co-grinding of solid diazonium salts with KI gives quantitative yields of various solid aryl iodides. The unavoidable coupling products in salt reactions are completely separated from the insoluble products in a highly benign manner. The solid-state reactions compare favourably with similar solution reactions that produce much waste. The structures of the products are elucidated with IR and NMR spectroscopy and mass spectrometry, while the tautomeric properties of the compounds are studied with density functional calculations at the B3LYP/6-31G* and BLYP/6-31G** levels.

(13)C NMR and X-ray Structure Determination of 1-(Arylazo)-2-naphthols. Intramolecular Proton Transfer between Nitrogen and Oxygen Atoms in the Solid State

The tautomeric reaction involving a single proton transfer in 1-(phenylazo)-2-naphthol and its 4'-methoxy, ethoxy, and N,N-dimethylamino derivatives has been investigated with variable-temperature solution and high-resolution solid-state (13)C NMR spectroscopy.Crystal structures of the parent unsubstituted compound and the 4'-N,N-dimethylamino derivative have been determined.All of these compounds undergo a fast proton exchange on the NMR time scale between the tautomeric azo and hydrazone forms in both solution and the crystalline phase.Equilibrium compositions inthe solid materials are similar to those measured in solution.Crystals of 1-(phenylazo)-2-naphthol are monoclinic, a = 27.875 (7), b = 6.028 (2), c = 14.928 (5) Angstroem, β = 103.57 (2)0, the space group is C2/c with Z = 8, and the structure at 213 K was refined to an R factor of 0.0414 on 1082 observed reflections.Crystals of 1-(azo)-2-naphthol are monoclinic, a = 7.604 (1), b = 7.970 (3), c = 24.381 (7) Angstroem, β = 99.33 (2)0, the space group is P21/c with Z = 4, and the structure at 193 K was refined to an R factor of 0.0405 on 1522 observed reflections.

1H-N.M.R. Spectroscopic Investigations of the Azo-Hydrazon-Equilibrium in Substituted 1-Phenylazo-2-naphthols

In substituted 1-phenylazo-2-naphthols an equilibrium between the azoic and the quinoid hydrazone form is observed.It is possible to obtain the equilibrium constants by means of 1H-n.m.r.-spectroscopy in CDCl3.Both chemical shifts δH-3 and δH-8 in the naphthalene ring system can be used to determine independently the equilibrium constants. 1-Phenylazo-2-naphthylamine and 1-(pyrid-2-ylazo)-2-naphthole were used as reference substances for the pure azoic and hydrazone form, respectively.An appropriate correction is introduced to compare the different influence of OH- and NH2-groups, respectively, on the protons H-3 and H-8.All equilibrium constants measured show a linear correlationship with respect to Hammett-?-constants of the substituents attached to the phenyl ring.The standard reaction entropy for the conversion of the azoic form into the hydrazone form is always negative and of nearly identical magnitude.Obviously, no substituent effect to this value exists.One possibility to interprete these results is to assume that the quinoid hydrazone form shows a higher tendency to aggregation.

Photooxidation of Arylazo-Naphtholes with Singlet Oxygen

The reaction of p-substituted 4-arylazo-1-naphtholes 1 and 1-arylazo-2-naphtholes 5 with singlet oxygen (produced by methylene blue-sensitized photolysis) has been studied spectroscopically in methanol as a solvent.The rate constants of dye bleaching are the same, irrespective whether the extinctions of the azo or the hydrazone forms of the tautomeric systems are measured.Both reaction series 1 and 5 afford linear Hammett plots, which is discussed in the light of the azo-hydrazone equilibrium of the dyes and an "ene" mechanism of the reaction with singlet oxygen.It could be shown by short-time spectroscopy that the azo-hydrazone isomerization proceeds much faster than the attack of singlet oxygen on the hydrazone form, which explains all observed facts.