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Issue 1279, 1982
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Determination of organic pharmaceuticals with N-bromosuccinimide. Part IV. Some pyrazolone derivatives by back-titration

Abstract

A back-titration method is described for the determination of pyrazolone derivatives with N-bromosuccinimide. Under the experimental conditions used, 4 molar equivalents of N-bromosuccinimide are consumed by aminophenazone (amidopyrine; 2,3-dimethyl-4-dimethylamino-1-phenyl-3-pyrazolin-5-one), morazone [2,3-dimethyl-4-(3-methyl-2-phenylmorpholinomethyl)-1-phenyl-3-pyrazolin-5-one] and propyphenazone (4-isopropyl-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one). With phenazone (2,3-dimethyl-1-phenyl-3-pyrazolin-5-one) and dipyrone [sodium (2,3-dimethyl-5-oxo-1-phenyl-3-pyrazolin-4-yl)methylaminomethanesulphonate] 5 molar equivalents are consumed. A reaction mechanism involving quaternisation of the N-methyl group at the 2-position, followed by ring cleavage and bromination of the aromatic ring, is proposed; this was confirmed by nuclear magnetic resonance spectral analysis of the brominated phenazone.

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Article type: Paper
DOI: 10.1039/AN9820701272
Analyst, 1982,107, 1272-1278

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    Determination of organic pharmaceuticals with N-bromosuccinimide. Part IV. Some pyrazolone derivatives by back-titration

    M. M. Amer, B. A. El-Zeany, A. M. Taha and O. A. El-Sawy, Analyst, 1982, 107, 1272
    DOI: 10.1039/AN9820701272

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