Benzene diazo hydroxide

Diazo Esters.—Before taking up the reactions of decomposition of diazo compounds there is one other class of derivatives which should be mentioned. As an acid compound benzene diazo hydroxide yields esterSy not by the direct action of alcohols, but by the action of alkyl halides upon silver diazotate. These esters are stable compounds like... 

Benzene diazo- and diazonium derivs 2 B54—B58 chemistry, definition and history 2 B54—B55 benzene diazonium chloride 2 BS5 benzenediazonium hydroxide and derivs 2 B55—BS6... 

Benzenediommonium Hydroxide. This compd, of which the Azido deriv is listed in Voi l,p A630 -L, should read Benzenediazonium Hydroxide. See under Benzene Diazo- and Diazomum Derivatives... 

Such a reaction agrees perfectly with the new formula which has been generally accepted as expressing the constitution of the free diazo base and the salts. The base thus takes the name benzene diazonium hydroxide and the salts, e.g., the chloride, benzene diazonium chloride signifying their ammonium character. The new formula does not, however, fit the reactions by which diazo. compounds are converted into azo or amino azo compounds nor the reduction of diazo benzene to phenyl hydrazine. Thus we have two formulas neither of which... 

Acids, Alkali Salts.—The free diazo benzene base which will always be spoken of now as benzene diazonium hydroxide and which necessitates the introduction of the pentavalent nitrogen formula is formed by the action of silver hydroxide upon benzene diazonium chloride. By the action of acids the diazonium hydroxide is converted into salts and these salts are neutral. If, however, the diazonium chloride is treated with alkalies, like potassium hydroxide, we obtain alkali metal salts of the diazo compound. 

The unconventional 3-diazoindoles were prepared by oxidative conversion of hydrazones and oximes. Thus, l-methyl-3-diazo-2-oxindole (21d) was prepared by mercuric oxide oxidation of l-methylisatin-3-hydrazone 297 (X = NNH2) in benzene at room temperature (1891JPR551) (Scheme 91). It can also be prepared by decomposition of l-methylisatin-3-tosyl-hydrazone 297 (X = NNHTs) with aqueous sodium hydroxide in a two-... 

The diazotization of the amines is carried out in the usual manner. The volume of water is kept at a minimum since the success of the reaction depends in part on the efficiency with which the unstable intermediate is extracted from the aqueous layer by the organic liquid. Either the previously prepared amine hydrochloride is employed or a paste of the hydrochloride is prepared by dissolving the amine in concentrated hydrochloric acid and then cooling rapidly with stirring. For diazotization a nearly saturated solution of sodium nitrite (1 g. in 2 cc. of water) is used. Little work has been done with very weakly basic amines in the diazo reaction.48 In one instance, the base, l-nitro-2-naphthylamine, was diazotized by means of nitrosylsulfuric acid in sulfuric acid benzene was added and then sodium hydroxide until the mixture was slightly alkaline.49 For the very weak bases, the nitrosoacetyl reaction is recommended, since it is carried out entirely under anhydrous conditions. 

Bases, Neutral Salts.— As a base it forms salts, in which form the diazo compound is obtained by diazotization, and which though also unstable has been isolated in small quantities and the composition and properties determined. Of the three salts, the sulphate, chloride and nitrate, the first is the most stable and the last is the least stable. They are colorless crystalline neutral compounds soluble in water, difficultly soluble in alcohol and insoluble in ether. After being prepared by the ordinary diazo reaction, with sodium nitrite in cold acid water solution, they may be precipitated in crystalline form by the addition of alcohol and ether. If the diazotization is effected in alcohol solution by means of amyl nitrite or ethyl nitrite the crystals of the diazonium salt separate at once. These salts of diazo benzene all show true salt characteristics, e.g., they lower the freezing point of solutions. The diazo radical, (CeHs—N2—) is thus basic toward strong acids, and the hydroxide, the non-isolated hypothetical diazo benzene, CeHs—N2—OH, is the free base. It may be considered as the simplest aromatic diazo compound and the mother substance of all other members of the class. 

Kekule Formula.—These facts led Kekule to suggest a second formula in which the nitrogen atoms are both trivalent and in the same relationship to each other and the ring as they are in azo benzene. The formula is CeHs—N=N—Cl, benzene diazonium chloride. For some time this was the accepted formula for, if we put it in the reactions which we have written for the formation of diazo compounds and for their conversion into azo compounds and into hydrazines, we find that it is satisfactory. It does not agree, however, with the true salt character of benzene diazonium chloride nor the strongly basic nature of the hydroxide compound, the free diazo benzene. In every respect the neutral salts, e.g., benzene diazonium chloride and the free diazo... 

Not only mono-sulphonic acids but also di- and tri-sulphonic acids are known. These all undergo the general reactions of the class as discussed under the sulphonic acid derivatives of benzene (p. 519). On fusion with potassium hydroxide they yield hydroxyl derivatives and similar fusion with potassium cyanide converts them into acid nitriles. They are characterized as soluble compounds and are readily coupled with diazo compounds yielding azo compounds many of which are dyes. ... 

This does not react as a diazo-compound unless a mineral acid is added to the solution. Bamberger called it an isodiazo -compound, which isomerises to a diazo-compound. By the action of hot concentrated potassium hydroxide solution on Griess s diazobenzene potassium (see p. 771), Schraube and Schmidt obtained an isomeric compound giving the diazo-reaction with acid. Von Pechmann and L. Frobenius found that the silver salt of /)-nitrodiazo-benzene with methyl iodide does not give a nitrosamine but the methyl ether CeH4(N02)-N N-0CH3, so that the nitrosamine formula appeared to represent a tautomeric form of diazobenzene. 

To 0.6 mole of silver oxide in 0.84 mole of sodium thiosulfate in 1 liter of warm water is added a 1 M dioxane solution of oi-diazo-o-phenylacetophenone. The mixture is stirred for 3 hr at room temperature while an additional quantity of freshly precipitated silver oxide (equal in amount to that used initially) is added in portions at intervals and the temperature is kept at 50°C for 1 hr. The solution is cooled and filtered and the residue washed with a 1 % sodium hydroxide solution. This slowly deposits a flocculent precipitate upon acidifying. The residue is again treated with about one-half the amount of silver oxide used above and worked up as before to yield a further quantity of product. The total yield of biphenyl-2-acetic acid is 86% mp 116°C (from benzene). 

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