Nitroso amines naphthol

Note Monohydroxybenzene derivatives and vicinal hydroxymethoxybenzene derivatives do not react under these conditions but can be made visible by spraying afterwards with Folin-Qocalteu s reagent [1]. Flavonoids, anthraquinone derivatives and a-nitroso-B-naphthol yield a red color with alkalis alone [1]. Steroids and aromatic amines do not react [1]. 

Nitroso-/3-naphthol has been made by the action of hydroxyl-amine hydrochloride on /3-naphtho-quinonc-chlorimide 1 by the action of sulfuric acid upon a solution of potassium or sodium nitrite and the sodium salt of /3-naphthol 2 by the action of sodium nitrite upon an alcoholic solution of zinc chloride and /3-naphthol 3 by the action of sodium nitrite upon /3-naphthol suspended in zinc sulfate solution 4 by the action of nitrous acid on /3-dinaphthol methane 6 and by the action of nitrosyl sulfate upon the sodium salt of /3-naphthol.6... 

The nitrosation of phenols proceeds in a manner similar to that of tertiary amines. For example, l-nitroso-2-naphthol has been prepared from the sodium salt of /9-naphthol by treatment with sodium nitrite and sulfuric acid near 0°C [29], This general procedure, suitably modified, has been used to prepare other nitrosophenols such as p-nitrosophenol (m.p. 135°-136°C) [30]. 

Aromatic tertiary amines and phenolic compounds undergo nuclear nitro sation, as illustrated by the synthesis of p>nitrosodimethyl aniline (89%)i nitrosophenol (80%), and l-nitroso-2-naphthol (99%) In the reaction of a-naphthol, an isomeric mixture of the nitrosonaphthols is obtained. The nitrosation of phenols with nitrous acid usually produces p nitroso compounds however, o-nitiosophenols can be prepared by nitrosating phenols in the presence of cupric sulfate. ... 

Related reagents, such as 2-nitroso-l-naphthol-4-sulphonic acid [31,32], 1-nitroso-naphthol-6-sulphonic acid, and 2-nitroso-l-naphthol-6-sulphonic acid [33] have also been recommended for determination of cobalt. The complexes with these reagents can be extracted into CHCI3 in the presence of amines [31,33]. 

By far the most stable nitroso compounds are those of the aromatic series. The smoothest C-nitrosation is achieved with phenols and tertiary amines having a free para-position. In benzene derivatives the nitroso group enters almost exclusively284 the para-position to the hydroxyl or amino group. In the naphthalene series the reaction is not always unidirectional 1-nitroso-2-naphthol is obtained almost quantitatively from 2-naphthol,285 but 1-naph-thol gives a mixture of about equal parts of 2- and 4-nitroso-l-naphthol.286... 

Naphthol N-nitroso 1-naphthol (1 mole) and N-nitrosodimethyl amine... 

Nitroso compounds are formed as intermediates in this reaction. Yields from sulfonic acids, carboxylic acids, and nitro compounds, amongst others, are poor,424 but those from tertiary amines and phenols are often very good,423,426 although naphthols give only the nitroso derivatives for example, yields are 70% from A,iV-diethylaniline,423 96% from phenol,426 98% from o- or 7W-cresol,426 95% from chlorophenol,426 and 75-85% from o-hydroxybenzene-sulfonic acid 428 the diazonium group enters para to the NR2 or OH group. 

The reactivity of the ethenediazonium salt 9.100 towards the nucleophiles mentioned shows that it has the properties of the corresponding carbocation, since it can ethylate the nucleophile and is prone to attack at the C()ff)-atom of the original ethene-l-diazonium ion. The thermal decomposition pattern is typical of that for an oxonium salt. Reactions with amines are similar to those of ketene acetals. No product that could be explained in terms of an azo coupling reaction, e.g., with 2-naphthol, could be observed. The electrophilicity of the diazonio group is, therefore, low. N-Azo coupling products with azide ions have been postulated with good arguments, however, by Kirmse and Schnurr (1977) with certain short-lived ethene diazonium intermediates produced from nitroso oxazolidones. 

The test is best used to distinguish primary aromatic and primary aliphatic amines from secondary and tertiary amines. It also differentiates aromatic and aliphatic primary amines. It cannot distinguish between secondary and tertiary amines. You will need to use infrared spectroscopy to make the distinction between secondary and tertiary amines. Primary aliphatic amines lose nitrogen gas at low temperatures under the conditions of this test. Aromatic amines yield a more stable diazonium salt and do not lose nitrogen until the temperature is elevated. In addition, aromatic diazonium salts produce a red azo dye when -naphthol is added. Secondary and tertiary amines produce yellow nitroso compounds, which may be soluble or may be oils or solids. Many nitroso compounds have been shown to be carcinogenic. Avoid contact and immediately dispose of all such solutions in an appropriate waste container. 

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