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Aromatic acids from diazo compounds

Aromatic nitriles (or aryl cyanides) can be obtained by methods (1) and (3). but not by method (2). In addition, aromatic nitriles can be prepared by two other methods, (a) from the corresponding diazo compound by Sandmeyer s Reaction (p. 189), (b) by fusing the corresponding sulphonic acid (or its salts)... [Pg.121]

Griess (1864a) had already observed that the diazo compounds obtained from primary aromatic amines in acid solution are converted by alkalis into salts of alkalis. The reaction is reversible. The compounds which Hantzsch (1894) termed sjw-diazotates exhibit apparently the same reactions as the diazonium ions into which they are instantaneously transformed by excess of acid. Clearly the reaction depends on an acid-base equilibrium. [Pg.3]

In the historical introduction to this book (Sec. 1.1) it was mentioned that the discoverer of diazo compounds, Peter Griess, realized quite early (1864 a) that these species could react with alkali hydroxides. Thirty years later Schraube and Schmidt (1894) found that the primary product from the addition of a hydroxide ion to a diazo compound can isomerize to form a secondary product. In this section we will discuss the equilibria of the first acid-base process of aromatic diazonium ions. In the following section additional acid-base reactions will be treated in connection with the isomerism of addition products of hydroxide ions to diazonium ions. [Pg.89]

Shortly after Perkin had produced the first commercially successful dyestuff, a discovery was made which led to what is now the dominant chemical class of dyestuffs, the azo dyes. This development stemmed from the work of Peter Griess, who in 1858 passed nitrous fumes (which correspond to the formula N203) into a cold alcoholic solution of 2-aminO 4,6 dinitrophenol (picramic acid) and isolated a cationic product, the properties of which showed it to be a member of a new class of compounds [1]. Griess extended his investigations to other primary aromatic amines and showed his reaction to be generally applicable. He named the products diazo compounds and the reaction came to be known as the diazotisation reaction. This reaction can be represented most simply by Scheme 4.1, in which HX stands for a strong monobasic acid and Ar is any aromatic or heteroaromatic nucleus. [Pg.180]

It is not possible to prepare biaryls containing a free carboxyl group directly by the diazo reaction. No biaryl is formed when (a) diazotized aniline and sodium benzoate, (b) diazotized anthranilic acid and aqueous sodium benzoate, or (c) diazotized anthranilic acid and benzene are used as components in the reaction.13 On the other hand, the reaction proceeds normally if methyl benzoate is used in reaction (a) or when methyl anthranilate replaces the anthranilic acid in (b) and in (c). The success of the diazohydroxide reaction appears to lie in the ability of the non-aqueous liquid to extract the reactive diazo compound from the aqueous layer.4 However, esters and nitriles can be prepared from esters of aromatic amino acids and cyanoanilines and also by coupling with esters of aromatic acids, and from the products the acids can be obtained by hydrolysis. By coupling N-nitrosoacetanilide with ethyl phthalate, ethyl 4-phenylphthalate (VIII) is formed in 37% yield. [Pg.234]

Salts of primary aromatic amines react with nitrous acid to produce diazonium salts. The reaction is usually performed by adding a cold solution of sodium nitrite to a cold solution of the arylamine in aqueous mineral acid. The end point of the reaction is conveniently determined by the detection of excess nitrous acid with potassium iodide-starch paper. Sulfamic acid has long been used both in industry and in the laboratory to remove excess nitrous acid. It has been found to react with the more active diazo compounds. In most cases, high temperatures are avoided to prevent the formation of phenols and the decomposition of the unstable nitrous acid. An excess of mineral acid is necessary to prevent coupling between the diazonium salt and unreacted amine (cf. method 494). If the amine salt is somewhat insoluble, a fine crystalline form, which is produced by rapid crystallization from a warm aqueous solution, may be employed. ... [Pg.391]

Phenyl Nitroso Amine.—Under certain conditions aniline, a primary aromatic amine, apparently undergoes this same reaction and yields a nitroso amine. If the potassium salt of diazo benzene, which is obtained from aniline by the action of nitrous acid and which will be explained later (p. 591), is heated, a change takes place involving space relations. The product is isomeric with the diazo compound and is known as the... [Pg.547]

Aromatic Acids.—hs, the cyanides are acid nitriles yielding the acids on hydrolysis, the above reaction gives us a means of passing from primary amines through the diazo compound to the acid nitrile and finally to the corresponding aromatic acid. [Pg.599]

Diazotization.—Like aniline and other aromatic primary amines they undergo diazotization. The resulting diazo compounds undergo the various diazo reactions (p. 601) by means of which the naphthalene group becomes coupled as an azo compound with other naphthalene or benzene rings. These azo compounds are dyes. The most important dyes of this group are derived from mixed amino and sulphonic acid or mixed amino and hydroxyl derivatives of naphthalene and will be considered a little later. Not only, however, may the naphthylamines >deld diazo compounds and through them azo compounds but they may be coupled as azo compounds with a diazotized benzene compound. [Pg.780]

Nickel peroxide, an undefined black oxide of nickel, is prepared from nickel sulfate hexahydrate by oxidation in alkaline medium with an ozone-oxygen mixture [929] or with sodium hypochlorite [930, 931, 932, 933]. Its main applications are the oxidation of aromatic side chains to carboxyls [933], of allylic and benzylic alcohols to aldehydes in organic solvents [929, 932] or to acids in aqueous alkaline solutions [929, 930, 932], and of aldehydes to acids [934, the conversion of aldehyde or ketone hydrazones into diazo compounds [935] the dehydrogenative coupling of ketones in the a positions with respect to carbonyl groups [931] and the dehydrogenation of primary amines to nitriles or azo compounds [936]. [Pg.37]

As already mentioned, under the preparation of methyl amine, the behaviour of the aliphatic primary amines toward nitrous add is very different from that of the aromatic compounds. While the former yield alcohols with the elimination of nitrogen, the latter, in a mineral acid solution, under the influence of nitrous add, yield diazo-compounds, discovered by Peter Griess, in the form of thdr mineral add salts. [Pg.210]

Through researches in aromatic chemistry it was not tong before synthetic phenol became available. Prior to work by Griess on aromatic diazo compounds published in 1860, Hunt (ref.1) had in 1849 obtained phenol from a diazonium salt produced by the reaction of aniline hydrochloride and siver nitrite. F.A. Kekule, (1829-1896), Fig.3, in 1867 (ref.2) described the recently completed sulphonation of benzene and fusion of the sulphonic acid with alkali as a new... [Pg.1]

Nitro compounds are reduced to the corresponding amine. Unlike hydride reductions, both alkyl nitro compounds (2-methyl-2-nitro-1,3-propanediol was reduced to l-amino-2-methyl-1,3-propanediol in 95% yield)566 and aromatic nitro derivatives [nitrobenzene was reduced to aniline with Ti(S04)3 in sulfuric acid and cetyltrimethylammonium bromide] are electrolytically reduced. 7 jf conditions are modified, reductive coupling can give azoxy compounds such as 568 (from 569) or diazo compounds. A variety of acid derivatives are reduced under electrochemical conditions, including nitriles (to amines), acids (to alcohols),5 E572 estejs (jq alcohols), and amides (to alcohols). It is possible to selectively reduce a cyclic imide to a lactam.575... [Pg.410]

Since Theodor Curtius reported the synthesis of ethyl diazoacetate in 1883, Buchner had investigated its reactions with carbonyl compounds, alkenes, alkynes, and aromatic compounds for more than 30 years.His extensive contributions in this area resulted in two reactions named in his honor the Buchner-Curtius-Schlotterbeck reaction (formation of ketones from aldehydes and aliphatic diazo compounds) and the Buchner reaction. The prototypical example of the latter involves the thermal or photochemical reaction of ethyl diazoacetate with benzene to give (via norcaradiene 7) a mixture of four isomeric cycloheptatrienes 8-11. Initially, Buchner believed that a single norcaradiene product 7 was generated from this reaction, but later, he realized that the hydrolysis of the product afforded a mixture of four isomeric carboxylix acids. The norcaradiene formulation persisted until 1956 when Doering reinvestigated this reaction. ... [Pg.424]


See other pages where Aromatic acids from diazo compounds is mentioned: [Pg.105]    [Pg.425]    [Pg.339]    [Pg.41]    [Pg.100]    [Pg.2]    [Pg.204]    [Pg.137]    [Pg.5]    [Pg.605]    [Pg.711]    [Pg.774]    [Pg.18]    [Pg.278]    [Pg.56]    [Pg.100]    [Pg.425]    [Pg.466]    [Pg.263]    [Pg.562]    [Pg.769]    [Pg.103]    [Pg.119]    [Pg.255]    [Pg.29]    [Pg.116]    [Pg.700]    [Pg.6]    [Pg.56]    [Pg.526]    [Pg.299]    [Pg.181]    [Pg.244]   
See also in sourсe #XX -- [ Pg.677 ]




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