Phenyl-3-amino-5-pyrazolone

1-PHENYL-3-AMINO-5-PYRAZOLONE (5-Pyrazolone, 3-amino-l-phenyl-) 

Submitted by H. D. Porter and A. Weissberger. Checked by R. T. Arnold and K. Murai. 

Sodium ethoxide is prepared from 46 g. (2 gram atoms) (Note 1) of sodium and 800 ml. of absolute ethanol in a 2-1. threenecked flask equipped with stirrer and a reflux condenser. To the hot solution is added 113 g. (106 ml., 1 mole) of ethyl cyano-acetate followed by 108 g. (98 ml., 1 mole) of phenylhydrazine (Note 2), and the mixture is stirred and heated in an oil bath at 

120° for 16 hours. Then most of the alcohol is removed under reduced pressure and the residue is dissolved in 1 1. of water the mixture is warmed to about 50° and stirred to facilitate solution. After cooling to room temperature, the solution is extracted with three 100-ml. portions of ether (Note 3). The aqueous phase is acidified by the addition of 100 ml. of glacial acetic acid, cooled in ice, and filtered. The crude product is washed on the filter with 100 ml. of 95% ethanol it is then transferred to a flask and boiled with 500 ml. of the same solvent, and this mixture is cooled and filtered. The solid is washed with ethanol and dried. The tan crystalline l-phenyl-3-amino-5-pyrazolone, melting with decomposition at 216--218°, weighs 76-82 g. (43-47%) (Note 4). 

At least two equivalents of sodium ethoxide are necessary for the reaction, but larger amoimts do not improve the yield. Sodium hydroxide in alcohol, or sodamide in benzene, cannot be substituted for the sodium ethoxide solution. 

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The absorbance of the red quinonamine dye formed in the reaction of phenol and 4-amino-l,5-dimethyl-2-phenyl-3-pyrazolone (4-aminoantipyrine) with periodate ions has been used in the estimation of periodate consumption in the oxidation of starch and other carbohydrates. The evaluation of the use of pyridine as a solvent in the oxidation of water-insoluble carbohydrates by periodate has been reported. The three types of dialdehydes produced by this oxidation were converted to the TMS ethers of the dithioacetals and measured by g.l.c. Oxidation proceeded in a normal Malapradian fashion but more slowly than it does in water. 

D(-)-reo-5-amino-2,2-dimethyl-4-phenyl-l,3-dioxane (C12H17NO2 147781-29-1) see Chloramphenicol 4-amino-2,3-dimethyl-l-phenyl-5-A -pyrazolone see under aminoantipyrine... 

The diazotized 3-amino-4-phenylpyrazolo[3,4- ]pyridine-5-carbonitrile 698 coupled with l-phenyl-3-methyl-5-pyrazolone 699 to yield 700, which cyclized (91G209) to the condensed pyrazolotriazine 701. 

A similar argument can be applied to the results of later work by Idelson et al.i9 In this they prepared the chromium complex (133) by interaction of the 1 1 chromium complex of 1-phenyl-3-methyl-4-(2-hydroxy-4-cyanonaphth-l-ylazo)-5-pyrazolone and diethylenetriamine and by reaction of the azo compound with [Cr(CO)3dien]. Identical products were obtained and, since the diethylenetriamine occupies9 a facial position in [Cr(CO)3dien], it was concluded that the complex (133) had a facial configuration. Similarly, the reported77 separation of isomeric 2 1 chromium complexes of 2-amino-6-(2-hydroxy-6-nitro-4-sulfonaphth-l-ylazo)-5-naphthol-7-sulfonic acid is... 

The fused 1,2,3-oxadiazepine system has been accessed via the reaction of l-phenyl-4-amino-5-(2-hydroxyphenyl)-3-pyrazolone 12 with hydrochloric acid and sodium nitrite <1945JA102> to give 13 that was characterized by melting point (245-250 °C) and combustion data (Equation 1). 

Diazo Components With Cycloammonium Groups. Polynuclear N heterocycles that carry an amino group in the carbocyclic aromatic ring can be diazotized and then joined to azo dyes by using aromatic or heterocyclic coupling components. Quatemization at the heterocyclic nitrogen atom may occur before or after coupling. The azo dye 43, from 2-methyl-5-aminobenzimidazole and l-phenyl-3-methyl-5-pyrazolone, used in the form of its hydrochloride, dyes paper and leather in clear yellow shades [130],... 

Compound 9 is prepared by 1 2 chromation in organic medium [12] Diazo-tized l-amino-2-hydroxy-4-nitrobenzene is coupled with 1-phenyl-3-methyl-5-pyrazolone. The resulting azo dye is heated at 110 °C in a mixture of formamide and a aqueous solution of chromium(m) formate. After completion of chromation, the dye 9 [64560-69-6] is precipitated with water. 

In the stepwise synthesis of the unsymmetrical complex dye 13 [ 70236-60-1] [10], the azo dye made from diazotized l-amino-2-hydroxy-5-nitrobenzene and 1-phenyl-3-methyl-5-pyrazolone and the 1 1 chromium complex obtained from 6-nitro-l-diazo-2-hydroxynaphthalene-4-sulfonic acid and 2-naphthol are heated together at 80 °C for 5 h. The adduct is salted out with NaCl. A black powder is obtained that dyes wool and leather in dark brown shades. The resulting colors are fast, particularly on shrink-resistant wool. 

Pyrazole (3 chloro,4 carboxy,1 methyl 5 sulfonamide) halosulfuron Pyrazole (1.4 dimethyl,2 chloro, 3 formyl) fenpyroximate Pyrazole (2 methyl, 3 amino, 4 carboxy) pyrazosulfuron Pyrazole (2 methyl,4 carboxy, ethyl ester) pyrazosulfuron Pyrazole (1 methyl,2 ethyl,4 chloro 5 carboxy) tebufenpyrad 5 Pyrazolone (1.3 dimethyl) benzofenap, pyrazolinate, pyrazoxyfen Pyridazine (1 phenyl 3 hydroxy, 6 oxo) pyridafenthion... 

N-Protection in peptide synthesis. Diketene reacts with an amino ester hydrochloride in ethanol at 0-5° in the presence of 1 equivalent of sodium ethoxide or a tertiary amine to give the often crystalline and easily purified N-acetoacetyl derivative (1). After peptide synthesis the protective group is removed by treatment with phenylhydrazine, which affords l-phenyl-3-methyl-5-pyrazolone. 

The pyrazolone can be incorporated directly in the polymer by utilizing a polymer-forming derivative such as a 1 -(amino or hydroxy -phenyl)pyrazolone in a phenol (or aniline)-formaldehyde polymerization. Alternatively, the pyrazolone nucleus can be combined with a synthetic or natural polymer by reaction of a functional group in the pyrazolone with the polymer. Thus, a 1-formylphenyl type is used to form a polyvinyl acetal. A compilation of such reactions is given in Part 1, Chapter II, Section 14, pp. 108-110. 

In mordant dyes, phenols, naphthols, and enolizable carbonyl compounds, such as pyrazolones, are generally the couplers. As a rule, 2 1 metal complexes are formed in the afterchroming process. A typical example of a mordant dye is Eriochrome Black T (18b) which is made from the important dyestuff intermediate nitro-l,2,4-acid, 4-amino-3-hydroxy-7-nitro-l-naphthalenesulfonic acid [6259-63-8]. Eriochrome Red B [3618-63-1] (49) (Cl Mordant Red 7 Cl 18760) (1,2,4-acid — l-phenyl-3-methyl-5-pyrazolone) is another example. The equilibrium of the two tautomeric forms depends on the nature of the solvent. 

Cyclocondensation of 3-methyl-l-(5-substituted-3-phenyl-lH-indol-2-ylcarbonyl)-5-(4fi)-pyrazolones with arylidene derivatives of malononitrile using a catalytic amount of triethylamine in refluxing ethanol affords heterocycle [ ]-fused 6-amino-4-aryl-5-cyano-4H-pyrans (14JHC303). Other fused 6-amino-4-aryl derivatives arise from the three-component reaction of benzaldehydes, active methylene compounds (malononitrile/ ethyl cyanoacetate) and 1,3-dicarbonyl compounds catalyzed by 1,8-diaz-abicyclo[5.4.0]undec-7-ene (DBU) in refluxing water (14JHC618). Similar pyrazole[f)]-fused derivatives are obtained from the reaction of benzaldehydes, malonitrile, and 3-substituted-2-pyrazolin-5-ones using sodium... 

Amino-1 -phenyl-pyrazolon-(5)-oaibon 8iure-(3) 26, II240. 

Melhyl.l-[4.cartathoxy amino-phenyl]. pyrazolon-(5) 24II22. 

Dimethyl-3-oxyinethyl.l [4-ditnethyh amino.phenyl].pyrazolon-(5) 36, 4, 1459. 

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