Phenol p-amino

Phenacetin may be conveniently prepared in the laboratory from p-amino-phenol. The latter is readily acetylated with acetic anhydride to give p-acetyl-aminophenol this Is ethylated in the form of the sodio derivative to yield acetyl p-phenetidine (phenacetin) ... 

In support of this view the p-amino-phenols themselves readily yield quinones. Also most p-substituted primary amines, e.g., p-diamines, p-alkylamines, such as p-toluidine, sulphanilic acid and its derivatives, behave similarly. In fact, the reaction can be used as a test for p-substi-tuted primary amines. p-Benzoquinone is usually made from aniline for the other p-quinones the p-amino-phenols, which are easily obtained by reduction of the p-nitroso-phenols and of azo-phenols, are employed. These reactions also apply, but not so widely, in the naphthalene series. 

The use of a fixed-bed cell with Cu particles as the cathode 576 has been suggested for the synthesis. p-Aminophenol, produced by electrochemical reduction of nitrobenzene, was used for the synthesis of hydroquinone 577). According to recent work, the addition of emulsifiers, for example, trialkylamine oxides 578), is supposed to suppress the formation of aniline as a byproduct. The electrosynthesis of p-amino-phenol from nitrobenzene is carried out industrially in India 276). 

Kl. Kind, P. R. N., and King, E. J., Estimation of plasma phosphatase by determination of hydrolyzed phenol with amino-antipyrine. J. Clin. Pathol. 7, 322-325 (1954). 

The differential reactivity of the sterically hindered and unhindered isocyanate groups of tolylene-2,4-diisocyanate facilitates the stepwise conjugation of hapten (R) and protein (P) amino groups (Fig. 3, Rn 7). jd.jj -Difluoro-m,m -dinitrobenzene (DFDNB) reacts with numerous functionalities including primary and secondary amines, imidazoles, and phenols to yield mixtures of conjugated materials (Fig. 3, Rn 8). This reaction is apparently harder to control than the diisocyanate reactions, but it is much more versatile. 

Suspend 11 g (0.1 mol) of p-amino phenol in 30 ml of water contained in a 250-ml beaker or conical flask and add 12 ml (0.127 mol) of acetic anhydride. Stir (or shake) the mixture vigorously and warm on a water bath. The solid dissolves. After 10 minutes, cool, filter the solid acetyl derivative at the pump and wash with a little cold water. Recrystallise from hot water (about 75 ml) and dry upon filter paper in the air. The yield of p-hydroxyacetanilide, m.p. 169 °C (IX is 14g (93%). 

This reaction, known as the Gatterman-Koch reaction, does not work with phenolic or amino aromatic species due to complex formation with the Lewis acid. It does work well with aromatic hydrocarbons and is used industrially to prepare benzaldehyde and, as here, p-tolualdehyde. 

The first of the organophosphorus insecticides to gain widespread use was parathion which is still an important commercial pesticide. This compound (Figure 9) is converted to the S-ethyl isomer by heating whereas paraoxon, a more toxic compound, is formed by enzymic action in plants. In animals, the additional products, p-nitrophenol and p-amino-phenol, are also formed. At present, little information appears to be available regarding the decomposition products of parathion in soils. 

Both the above mechanisms are proposed in the literature with Mannich bases of nitroalkanes the substitution is clearly favored by the steric hindrance of the amine moiety, thus suggesting path 1, - whereas NMR studies on the reaction of P-amino-ketones with hydroxy coumarins do not reveal the presence of vinyl ketone intermediates. lodomethylated phenolic Mannich bases arc also claimed to react according to path 2, although the formation as by-products of dimers and methylene-bis-derivatives accounts for the participation of methylenequinone intermediates in the process. "... 

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