Phenols with mercuric oxide

The mechanism of oxynitration is generally accepted to involve the formation of phenyl mercuric nitrate which reacts with nitrogen oxides in the nitric acid to form a nitroso compound and then a diazonium salt the latter forms a phenol under the aqueous conditions which is then further nitrated. The use of more concentrated nitric acid favours a process of mercuration-nitration and suppresses the formation of phenols. ... 

If 1-alkyl- or l-aryl-l,2-dihydro-X -phosphorins 147 (obtained by Method B, p. 78) are oxidized with mercuric acetate in the presence of alcohols or phenols as nucleophiles, it is possible to isolate X -phosphorins 156 in which the phosphorus bears a carbon substituent besides an alkoxy or phenoxy group (Markl ° ). 

M. Berthelot. found that many nitrogenous organic compounds furnish ammonia when heated with hydriodic acid and J. Kjeldahl showed that the nitrogen of many nitrogenous compounds is all converted into ammonia or ammonium sulphate when heated with cone, sulphuric acid—in the case of nitro-eompounds and cyanides the reaction is not always quantitative. The reaction proceeds more satisfactorily in the presence of mercury or mercuric oxide, copper, potassium hydrosulphate, sugar, phenol, benzoic acid, and analogous compounds. This reaction has been discussed by C. Arnold, A. Atterberg, C. Budde and C. V. Sehon,... 

Freshly precipitated mercuric oxide and the calculated quantity of dinitrophenol are boiled together in aqueous solution for sixteen hours, a lemon-yellow powder resulting which is only slightly soluble in water or alcohol, and insoluble in other solvents except pyridine. When heated witli the latter it forms a double compound which may be precipitated by the addition of ether. This derivative is dark yellow in colour and is decomposed when heated, and in aqueous solution it yields no mercury ions. When the anhydride is treated with bromine, o-bromodinitro-phenol is formed, and with dilute hydrochloric acid the chloromercuri derivative is obtained, a colourless, crystalline powder, M.pt. 182° C. with decomposition,... 

The preparation of 2,4-dinitrophenol107 serves as example of the procedure Mercuric oxide (60 g) is dissolved in 70% nitric acid (541 ml) contained in a 1.5-1 flask fitted with a stirrer, reflux condenser, and dropping funnel. The solution is diluted wih water to 750 ml, then sodium nitrite (0.1 g) is added. Benzene (50 g) is dropped in at 50° during 200 min and the mixture is stirred for a further 160 min at 50° and then allowed to cool. 12 Hours later the product is filtered off and washed with dilute nitric acid and then with cold water it has m.p. 112-113°, the yield being 67 g. If the filtrate is worked up, a total of 68% of dinitro-phenol is obtained. 

Mandelaldehyde, PhCH(OH)CHO, can be condensed with 7V-phenyl-ethanolamine under acid catalysis to afford the 5,6-dihydro-1,4-oxazine (393) (80%) none of the isomeric oxazolidine is formed.""" Oxidation of isatins with peroxodisulphate gives excellent yields of 2,3-dioxo-benzo[Z>]-l,4-oxazines (394), in contrast to the formation of isatoic anhydrides by oxidation with a peroxide." Benzo[f>]-l,4-oxazines that are functionalized with methylene at position 2, i.e. (395), are obtained in good yields by the mercuric-oxide-promoted cyclization of o-(propargylamino)phenols." ... 

Structure. Coreximine has two methoxyls and two phenolic hydroyls, and when methylated with diazomethane it yields a tetramethoxy compound, melting at 177°. Ethylation similarly yields a dimethoxydiethoxy base melting at 131° (28). The tetramethoxy compound is isomeric but not identical with tetrahydropalmatine, and like the latter it is readily oxidized in air to a yellow base, and when racemized by oxidation with mercuric acetate followed by reduction with zinc and hydrochloric acid it gave rise to a base (m.p. 157°) identical with norcoralydine (LXIX) (227). Coreximine is therefore a bisdesmethyl derivative of LXIX (271). Four such compounds are possible if vicinal hydroxy compounds are excluded. 

Oxidation of phenols and hydroqumones. Mercuric oxide in methanol oxidizes these substances to quinones. Mercury(II) trifluoroacetate can also be used, but then an acid scavenger is necessary tO neutralize the trifluoroacetic acid formed. The oxidation is analogous to that with thallium(III) salts. Yields in the oxidation of p-hydroquinones with HgO are in the range 70-95%. 

One of the most versatile methods for the preparation of 1,1-disubstituted X -phosphorins 124 was discovered by Stade who found that X -phosphorins 2 can be oxidized (mercuric acetate gives the best results) in the presence of alcohols or phenols in benzene to 1.1-dialkoxy- or l.l-diphenoxy-X -phosphorins 124. The first step is probably a reaction of the soft X -phosphorin- jr-system with the soft acid Hg which by electron transfer leads to the weakly electrophilic radical cation 58. This is then attacked by alcohol or phenol - or as Hettche has found by other nucleophiles such as an amine to form by loss of a proton the neutral X -phosphorin radical 59. This radical is oxidized once again by mercury ions leading to the formation of elemental mercury and the strongly electrophilic, short-lived X -phosphorin cation 127, which is immediately attacked by alcohol, phenol or amine. Loss of a proton then leads to the X -phosphorin 124. It is also conceivable that 59 can couple directly with a radical to form 124 (Method E, p. 82). 

Thin-layer chromatography has frequently been used to separate isoquinoline cactus alkaloids (231,232) and many of the phenolic isoquinolines (233). The oxidation of TIQs with an NH group to imines by mercuric... 

In contrast to aliphatic alcohols, which are mostly less acidic than phenol, phenol forms salts with aqueous alkali hydroxide solutions. At room temperature, phenol can be liberated from the salts even with carbon dioxide. At temperatures near the boiling point of phenol, it can displace carboxylic acids, e.g. acetic acid, from their salts, and then phenolates are formed. The contribution of ortho- and -quinonoid resonance structures allows electrophilic substitution reactions such as chlorination, sulphonation, nitration, nitrosation and mercuration. The introduction of two or three nitro groups into the benzene ring can only be achieved indirectly because of the sensitivity of phenol towards oxidation. Nitrosation in the para position can be carried out even at ice bath temperature. Phenol readily reacts with carbonyl compounds in the presence of acid or basic catalysts. Formaldehyde reacts with phenol to yield hydroxybenzyl alcohols, and synthetic resins on further reaction. Reaction of acetone with phenol yields bisphenol A [2,2-bis(4-hydroxyphenyl)propane]. 

Samples with particulate matter may present quite serious problems, and it may be desirable to remove particles, for example, by centrifugation, and examine this fraction by procedures applicable to solid phases which are discussed in Section 2.2.5. Tangential-flow high-volume filtration systems have been used for analysis of particulate fractions (>0.45 jum) where the analytes occur in only low concentration (Broman et al. 1991). Attention has already been drawn to artifacts resulting from reactions with cyclohexene added as an inhibitor to dichloromethane. It has also been suggested that under basic conditions, Mn2+ in water samples may be oxidized to Mn(III or IV) which in turn oxidized phenolic constituents to quinones (Chen et al. 1991). Serious problems may arise if mercuric chloride is added as a preservative after collection of the samples (Foreman et al. 1992) since this has appreciable solubility in many organic solvents, and its use should therefore be avoided. 

CARBONIC ACID, LITHIUM SALT (554-13-2) LijCOj Aqueous solution is an organic base. Violent reaction with acids. Inconpatible with fluorine, germanium, lead diacetate, magnesium, mercurous chloride, silicon, silver nitrate, titanium. Aqueous solution incompatible with organic anhydrides, acrylates, alcohols, aldehydes, alkylene oxides, substituted allyls, cellulose nitrate, cresols, caprolactam solution, epichlorohydrin, ethylene dichloride, isocyanates, ketones, glycols, nitrates, phenols, vinyl acetate. Exothermic decomposition with maleic anhydride. Corrodes aluminum, copper, zinc in the presence of moisture. On small fires, use any extinguishing agent. 

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