Cresols nitroso

The nitrosation of phenol and cresols in buffer solutions involves a diffusion-controlled C-nitrosation followed by rate-limiting proton loss. /r-Crcsol is much less reactive than the other substrates.79 Nitrosation in trifluoroacetic acid or in acetic-sulfuric acid mixtures is regioselective (e.g. 4-nitroso-m-xylene is fonned from m-xylene) and possible non-selective nitrous acid-catalysed nitration can be eliminated by purging reaction solutions with nitric oxide.80... 

While the mtrosation of phenols occurs at least as readily as that of tertiary aromatic amines -such as dimethylaniline, the conditions must be very carefully controlled owing to the ease with which most phenols oxidize. For this reason a higher proportion of tarry by-products is formed and the yields are smaller than in the case of the dialkylanilines. Taking o-cresol as a typical example of a phenol with an unsubstituted para- position, the main product of the reaction is />-nitroso-o-cresoL... 

Summary Methylpicric acid is prepared from a nitroso intermediate, which is prepared by reacting m-cresol with sodium nitrite and sodium hydroxide. Afterwards, the nitroso intermediate is then nitrated with nitric acid forming methylpicric acid. The methylpicric acid is then collected by filtration, washed, and dried. Commercial Industrial note For related, or similar information, see Application No. 365,208, May 30, 1973, by David Anthony Salter, 35, Roseacres, Takely, Essex, England, Robert John James Simkins, 3, Upper Park, Harlow, Essex, England. Part or parts of this laboratory process may be protected by international, and/or commercial/industrial processes. Before using this process to legally manufacture the mentioned explosive, with intent to sell, consult any protected commercial or industrial processes related to, similar to, or additional to, the process discussed in this procedure. This process may be used to legally prepare the mentioned explosive for laboratory, educational, or research purposes. 

The direct nitration of m-cresol is unsatisfactory for obtaining 4-nitro-3-methylphenol (29%). A better procedure is to form the nitroso compound and oxidize it to the nitro compound (66% over-all). ... 

Solid sodium nitrite (35 g., 0.51 mole) is added to a stirred suspension of 27 g. (0.25 mole) of o-cresol in 2 1. of ice-water slurry. A solution of 9.5 ml. of concentrated sulfuric acid in 200 ml. of water is added over a 1-hour period, the temperature being held below 5° by the further addition of ice. The mixture is allowed to stand for 2 hours, and the nitroso compound is filtered off and washed with water. Recrystallization of a small amount of the product from benzene gives pure 2-methyl-4-nitrosophenol, m.p. 136°. 

C7H6N604 5-(N-methyl-N-nitroso)amino-3-(5-nitro-2-fur 41735-28-8 25.00 1.6632 2 10525 C7H7CIO 5-chloro-o-cresol 5306-98-9 19.83 1.1954 2... 

Another very convenient method which gives a homogeneous product in good yield involves the oxidation of /j-nitroso-o-cresol to the p-mtro derivative, as given by Borsche and Berkhout,8 except that almost quantitative yields are obtained m the cold instead of on boiling as recommended by these authors... 

Substituents in the ortho- or meta-position to a hydroxyl group usually do not interfere. Thus o- and m-cresol afford the 4-nitroso derivatives (OH = l).292 / -Substituted phenols react differently, if at all p-cresol, for instance, is nitrated in the ortho-position to the hydroxyl group by nitrous acid.292... 

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. 

In addition, m-cresol is used to produce plant protection agents such as feni-trothion. The manufacturing process involves nitrosation of m-cresol with nitrous acid esters in isopropanol, and subsequent oxidation of the nitroso compounds with nitric acid to yield 4-nitro m-cresol (or its sodium salt), which, when acted upon by 0,0-dimethyl thiophosphoric acid chloride, gives fenitrothion. 

Unlike the reaction of nitrous acid with p-cresol, the product of a similar reaction with resorcinol, has been proved< > without doubt, by comparison with 2,4-dinitrosoresorcinol, to be the nitroso-compound. The procedure is ... 

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