Methyl-phenyl-pyrazolone, preparation

The preparation of methyl-phenyl-pyrazolone illustrates one of the synthetic uses of ethyl acetoacetate, as distinct from those involving the hydrolysis of substitution derivatives. 

Mix 6 2 ml. (6 4 g.) of pure ethyl acetoacetate and 5 ml. of pure phenylhydrazine in an evaporating-basin of about 75 ml. capacity, add 0 5 ml. of acetic acid and then heat the mixture on a briskly boiling water-bath (preferably in a fume-cupboard) for I hour, occasionally stirring the mixture with a short glass rod. Then allow the heavy yellow syrup to cool somewhat, add 30-40 ml. of ether, and stir the mixture vigorously the syrup may now dissolve and the solution shortly afterwards deposit the crystalline pyrazolone, or at lower temperatures the syrup may solidify directly. Note. If the laboratory has been inoculated by previous preparations, the syrup may solidify whilst still on the water-bath in this case the solid product when cold must be chipped out of the basin, and ground in a mortar with the ether.) Now filter the product at the pump, and wash the solid material thoroughly with ether. Recrystallise the product from a small quantity of a mixture of equal volumes of water and ethanol. The methyl-phenyl-pyrazolone is obtained... 

Heterocyclic azo couplers have also featured prominently in disperse dye chemistry, especially in the production of yellows. Cl Disperse Yellow I (B-71MI11202) is in fact an azo dye prepared from benzenediazonium chloride and l-phenyl-3-methyl-5-pyrazolone, and pyrazolone couplers continue to appear in patents. However, the most important recent development has been the introduction of 2,6-dihydroxypyridine couplers in azo dyes such as (54). Although the couplers had been disclosed some time ago, their development by... 

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. 

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... 

Pyridine-pyrazolone solution Prepared by mixing saturated solutions a and b. Solution a is made by dissolving 0.25 g of 3-methyl-l-phenyl-2-pyrazolin-5-... 

Diacetoxymercuri - 4 ethoxy - 1 - diacetoxymercuri-phenyl-2 3-dimethyl-5-pyrazolone is prepared in a similar manner to the 4-methoxy compound, but the methyl alcohol in the latter preparation is now replaced by ethyl alcohol. Yield 96-6 per cent. It forms small, colourless needles vhich crystallise with 1 mol. of water, which may be removed by heating in vamo over phosphorus pentoxide at 110° C. It has similar solubilities to the methoxy compound, and hydrochloric acid removes the mercury in the 4-position. 

A water-soluble sulfonated crown ether (see Figure 80) has been prepared and used as an ion size selection reagent. In the synergistic extraction of alkaline earth ions with 4-benzoyl-3-methyl-1-phenyl-5-pyrazolone and trioctylphosphine oxide in cyclohexane, addition of the sulfonated crown ether shifted the extraction for the larger ions to a higher pH level, thereby improving the... 

It may be prepared by the eondensation of one mole each of phenyl-hydrazine and the lactim-form of ethylacetoacetate when 1-phenyl-3-methyl-pyrazolone is obtained by the elimination of a mole each of water and ethanol. The resulting product is subjected to methylation either with methyl iodide or dimethyl sulphate to yield phenazone. 

As a consequence of the success of rationally designed tris-bidentate ligands for the straightforward synthesis of [M4L4] tetrahedra (see Sect. 2.4.1), the three-fold symmetric, tris-bidentate pyrazolone-based ligand H3L 30 was prepared. Tris-diketone ligand 30 is generated from 3-methyl-1-phenyl-2-... 

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