Phenylhydrazine, reaction with methods

The purity and identity of diethyl chlorothiophosphate prepared by new methods were checked by reaction with phenylhydrazine according to the directions of Mastin, Norman, and Weilmuenster (7). 

Diphenylhydrazine is oxidized to diphenylnitrosamine (50%) by potassium superoxide. The same reagent also oxidizes 1-methyl-1-phenylhydrazine, but here the nitrosamine is a minor product the major reaction is deamination. A better meAod of oxidative deamination of some 1,1-disubstituted hydrazines and hydrazinium salts is reaction with nitrous acid. Thus, several hydrazinium salts MezRN NHi X were deaminated to the tertiary amine by treatment with nitrous acid. The method has also been used to deaminate IV-aminoheterocyclic compounds for example, some 1,2,3-triazoles are conveniently prepared by deamination of the corresponding 1-aminotriazoles with nitrous acid. °... 

Cleavage of phthaloylpeptides. The conventional method of removing the N-protective phthaloyl group of a peptide involves reaction with hydrazine in alcoholic solution and heating the intermediate formed with dilute acid to effect hydrolysis. Boissonnas found that cleavage can be effected more easily and in one step by heating in alcoholic solution with phenylhydrazine and a tertiary amine. For example, a solution of 535 mg. (2.05 mmoles) of phthaloyl-L-leucine, 0.5 ml. (2.1 mmoles) of Iri-n-butylamine, and 0.405 ml. (4.1 mmoles) of phenylhydrazine in 3 ml. of ethanol... 

Two reactions used in steroid chemistry were modified by Bennett for histochemical use. Frozen sections of either unfixed or formalin-fixed tissue were used, with no differences reported in their reactivity (see, however, Section V.2) the sections were 80 to 100 microns in thickness. In the first method, sections were treated with phenylhydrazine hydrochloride (1 %) in acetate buffer, pH 6 to 6.5, overnight. The formation of yellow phenylhydrazones indicated the presence of carbonyl groups. The pH of the solution was kept low enough to prevent extensive accumulation of the decomposition products of phenylhydrazine, which are yellow and soluble in lipid. In order to avoid reaction with ascorbic acid the sections were first oxidized briefly with iodine or indophenol. Since dehydro-ascorbic acid, which is formed by the oxidation of ascorbate, also forms phenylhydrazones, it is doubtful that this procedure had any value. However, since ascorbic acid and its oxidation product are soluble in most aqueous mixtures, they probably would not remain in sections as ordinarily treated. 

Afkhami A, Zarei AR (2004) Simultaneous spectrophotometric determination of hydrazine and phenylhydrazine based on their condensation reactions with different aromatic aldehydes in micellar media using H-point standard addition method. Talanta 62 559-565... 

Historically, techniques such as the formation of osazones and the demonstration of fermentation have contributed significantly to the separation and identification of carbohydrates. Observation of the characteristic crystalline structure and melting point of the osazone derivative, prepared by reaction of the monosaccharide with phenylhydrazine, was used in identification. This method is not completely specific, however, because the reaction involves both carbon atoms 1 and 2 with the result that the three hexoses, glucose, fructose and mannose (Figure 9.19), will yield identical osazones owing to their common enediol form. 

It has been shown by H naff (1963) that the rate of reaction of several carbonyl reagents (bisulphite, hydrazine, phenylhydrazine, semi-carbazide and hydroxylamine) with aqueous formaldehyde solutions is independent of the nature and concentration of the reagent, and is therefore determined by the rate of dehydration of methylene glycol. He obtained catalytic constants for hydrogen and hydroxide ions, and a detailed study of acid-base catalysis has been made by the same method by Bell and Evans (1966). 

The reactivity of the keto group is not influenced by the substitution the reaction of 3-(trifluoromethylmercapto)-2-butanone with hydroxyl-amine hydrochloride gives the corresponding oxime in good yield. Cyclization of diketones and keto esters to pyrazole derivatives succeeds by the well-known method using phenylhydrazine ... 

This method is specific for the 17,21-dihydroxy-20-keto corticosteroids (such as cortisone and hydrocortisone). The method depends upon the action of sulfuric acid with the 17,21-dihydroxy-20-keto groups to give rise to a glyoxal side chain. Subsequent condensation with phenylhydrazine yields a stable yellow color. This reaction was developed by Porter and Silber [98], and its mechanism was elucidated by Lewbart and Mattox [99] as follows ... 

A systematic investigation of the phenylation of thiophene with phenyl radicals generated by different methods has been carried out (73IJS295). Phenyl radicals have been produced by the following methods (i) Gomberg reaction (ii) oxidation of phenylhydrazine (iii) thermal decomposition of AT-nitrosoacetanilide (iv) thermal decomposition of... 

As reported by Mannich (29AP(267)699>, reaction of ethyl cyclopentanone-2-carboxylate with phenylhydrazine and subsequent cyclization of the phenylhydrazone at elevated temperature under strongly basic conditions gives tetrahydro-2-phenylcyclopentapyrazol-3-one (equation 19) (a = b = CH2). The method has been used to prepare thieno[3,4-c]pyrazol-3-ones, thieno[3,2-c]pyrazol-3-ones and pyrrolo[3,4-c]pyrazolones (71JMC454,71JMC1129). 

Fig. 9. Fischer s phenylhydrazone reaction85 and the glycoblotting method first demonstrated by using aminooxy-functionalized synthetic polymers. (A) Reaction of sugars with phenylhydrazine (B) the general concept of glycoblotting and (C) the aminooxy-functionalized synthetic polymers used in the preliminary study.84 (Original figure made by the author.)...

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