2,4 Dinitro-l-naphthol

Naphthalenol also is used ia the preparation of azo, iadigoid, and nitro, eg, 2,4-dinitro-l-naphthol, dyes, and ia making dye iatermediates, eg, naphtholsulfonic acids, 4-chloro-1-naphthalenol, and l-hydroxy-2-naphthoic acid. 1-Naphthalenol is an antioxidant for gasoline, and some of its alkylated derivatives are stabilizers for plastics and mbber (68). 

Dinitro-l-naphthol (Martins Yellow) [605-69-6] M 234.2, m 81-82 , pKest 3.7. Crystd from benzene or aqueous EtOH. 

Tri nitro-1 -N aphthol (2,4,7 -Trinitro-1 -oxy-naphthalene). Yellow prisms from AcOH or benz, mp 145° (decompn). Sol in AcOH glac AcOH. Prepn from 2,4-dinitro-l-naphthol by mixed acid (nitric-sulfuric-acetic) nitration. The compound is extracted as the Na salt from... 

Flavionic Acid. Same as 2,4-Dinitro-l-naphthol-7-suIfonic Acid, which.will be described under Naphthol Sulfonic Acids... 

To a mixture of 103 grams of 62 per cent nitric acid (40° B6) and 300 grams of 80 per cent sulfuric acid, 128 grams of naphthalene is added. The mixture is stirred continuously for 6 hours at 50°C., and then the temperature is raised to 60° during the course of 1 hour. On cooling the mixture, the nitronaphthalene floats as a porous cake on the surface of the acid. It contains about 90 to 92 per cent of the o-nitro compound, 4 to 5 per cent of the j3-nitronaphthalene, 2 to 3 per cent of dinitronaphthalene, and about 0.5 per cent of 2,4-dinitro-l-naphthol (Martins yellow). 

Dinitro-l-naphthol-7-sulfonic acid (naphthol yellow S)... 

DINITRO-l-NAPHTHOL see DUX800 2-4 DINITRO-a-NAPHTOL see DUX800... 

Set aside an estimated 0.3 g of the moist ammonium salt. This sample is to be dissolved in hot water, the solution acidified (HCl), and the free 2,4-dinitro-l-naphthol (1) crystallized from methanol or ethanol (use decolorizing charcoal if necessary) it forms yellow needles, mp 138°C. 

Reeves and co-workers [76] correlated the change in the chemical shift of NMR spectra caused by formation of an intramolecular hydrogen bond in o- ubstituted phenols including o-nitrophenol, 2,4-dinitrophenol, I-nitro-2-naphthol, 2,4-dinitro-l-naphthol etc. 

Hodgson and Smith found that with use of just 3 equivalents of stannous chloride 2,4-dinitro-l-naphthol can be reduced selectively to 2-nitro-4-amino-l-napthol. A suspension of the dinitro compound in coned, hydrochloric acid and ethanol was OH... 

Note that in the partial reduction of 2,4-dinitro-l-naphthol with alcoholic stannous chloride to 2-nitro-4-amino-l-naphthol6 the nitro group selectively reduced is not that ortho to the hydroxyl group but that in the reactive a-position of the naphthalene nucleus. 

Yellow needles from CgH . M.p. 146-5°. Sol. AoOH, hot MsjCO. Spar. sol. EtOH, EtjO, wai-m ligroin. Warm dil. alkalis —> 2 4-dinitro-l-naphthol... 

Other Names Acid Yellow 24 1-Naphthol, 2,4-dinitro- l-Hydroxy-2,4-dinitronaphthalene 2,4-Dinitro-l-naphthol 2,4-Dinitronaphthol Martinsgelb Martius yellow Manchester Yellow NSC 6148... 

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