Anthranilic acid, diazotization with

Anisole, chlorination with sulfuryl chloride, 47, 23, 49,16 Anisole, /i-a-mcHLORO-, 49,16 Anthranilic acid, diazotization with isoamyl nitrite and trichloroacetic acid, 48,13, IS... 

Reaction with benzyne. Benzyne generated from diazotized anthranilic acid reacts with phenylacetylene to give the two hydrocarbons formulated. Surprisingly, it reacts with ethoxyacetylene to form 2-ethoxyphenylacetylene. 

Aprotic diazotization of anthranilic acid, usually with pentyl nitrite, gives benzyne via the reaction sequence shown in Scheme 1. The intermediate benzenediazonium-2-carboxylate (4) is explosively unstable, but if it is isolated by performing the first step at 0°C it provides a clean source of benzyne... 

Benzyne generated in situ by diazotization of anthranilic acid adds readily to aminides 172 to provide cycloadducts 171. Introduction of a nitro group into para position of the phenyl ring on the nitrogen terminus of the 1,3-dipole (X2 = N02) stabilizes the system and results in higher yields of product 171 (70% vs. 50% forX2 = H). Electron-deficient imines react also with aminides 172, but the yields of isolated adducts 173 are relatively low (10-26%) (Scheme 19) <2003ARK(vii)110>. 

Methyl red was first prepared 1 by diazotization of anthranilic acid in alcoholic solution, the product being allowed to react with dimethylaniline in the same solvent. It has been stated 2 that this process does not work satisfactorily and yields a different product, of brownish-red color. 

Benzotriazole and its derivatives are usually obtained by diazotization of o-phenylenediamines as discussed in Section 4.01.8.3 and in CHEC-1 <84CHEC-i(5)722>. Substituted o-phenylenediamines (e.g., 849) similarly give 1-substituted benzotriazoles (850) upon treatment with NaNOz (Equation (87)) <92JHC1519>. 1-Arylbenzotriazoles are alternatively synthesized from the cycloaddition of an aryl azide to benzyne or substituted benzynes, generated from the diazotization of anthranilic acid or its appropriately substituted derivatives (Scheme 169) <86CC399,87JCS(Pl)403, CHEC-i>. 

Acylhydrazides of anthranilic acid (35, R = NHCOR ) give 3-acylamino-l,2,3-benzotriazin-4(3H)-ones (10, R = NHCOR on treatment with nitrous acid. The triazine hydroxamic acid (40) and its benzo-substituted derivatives are available by diazotization of the corresponding o-aminobenzohydroxamic acids. The pyrido[2,3-e]triazine analog (41) was prepared similarly from 3-aminoisonicotino-hydroxamic acid, but the isomeric 2-aminonicotinohydroxamic acid failed to react under the same conditions to give 42. ... 

The melting point of the />-toluenesulfonylanthranilic acid is not a good criterion of purity because the />-toluenesulfonic acid salt of anthranilic acid has about the same value. The neutral equivalents are widely different 154 for the salt and 291 for p-toluenesulfonylanthranilic acid. The compound obtained in this preparation gives a negative test for anthranilic acid on diazotization and treatment with alkaline /3-naphthol solution. The probable impurity is the sodium salt of -toluene-sulfonylanthranilic acid. 

Diphenic acid has been prepared by the reduction of diazotized anthranilic acid with cuprous ion,5 Ullman coupling of potassium... 

The two heterocyclic rings of this system (485) were formed upon coupling salts of diazotized anthranilic acid (87JHC227) or diazotized anthranilic acid ester (88MI1) with butenonitriles. 

Lester Friedman and Frauds M. Logullo prepared substituted benzynes by diazotizing substituted anthranilic acid. This is a mild, room-temperature reaction which permits simultaneous reactions of the benzynes with suitable acceptors to prepare halogen. —NO , — ClL. and —OCH3 derivatives. They have also prepared new heterocyclic arynes, such as 3-pyridine from 3-amino-isonicotinic add. 

Carboxy-phenyl] 3(oder l) cyanguanyl -triazen-(l) 2- [Cyanoguanyl-triazeno] -benzoesaure or [2-Carboxy-benzoldiazo] dicyandiamid in Ger), HOOC.C6H4,N N.NH.C-( NH).NH.CN mw 232.20 N 36.20% yel crysts (from MeOH), mp dec ca 98° readily sol in hot ale si sol in benz, eth or chlf insol in w was prepd by treating diazotized anthranilic acid with dicyandiamid in alksoln.Its Silver salt... 

V-Hydroxycarbazole (326) was first postulated (64JOC2808) as an intermediate in the reaction of benzyne with nitrosobenzene, which gave N-phenylcarbazole. Later it was obtained in 1% yield from diazotized anthranilic acid and nitrosobenzene, while tetrahalogenated benzynes,... 

Diphenic acid has been prepared by the reduction of diazotized anthranilic acid with cuprous ion,6 Ullman coupling of potassium o-bromobenzoate,6 and oxidation of phenanthrene or phen-anthrenequinone with various oxidizing agents.7 The latter methods have been reviewed recently.7 The ozonolysis method has also been carried out in solvents 8 that do not react with the zwitterion intermediate. ... 

Diphenic acid was first prepared by oxidizing phenanthrene-quinone with chromic acid.1 Many later workers2 have modified this process in minor details. Vorlander and Meyer 3 were the first to prepare diphenic acid from diazotized anthranilic acid and cuprous oxide, but their process is not well adapted to large scale preparation. Inasmuch as pure phenanthrene is now very difficult to obtain in quantity, the present process was devised for relatively large scale operation. 

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. 

Ind 1953, 1179-80 drew attention to previous reports on expl nature of the reaction betn certain diazotized substituted benzenes and Na poly sulfides and stated that not all the reactions lead to the formation of such compds. For example, when diazotized anthranilic acid was treated with Na polysulfide (as in common use in... 

With rather insoluble arylamincs, such as anthranilic acid, the diazolizing reaction mixtures were stirred overnight to ensure completioit of the reaction. With very readily soluble amines, such as aniline, there was no need for the use of CH2CI2, and 1,2-dichlorobenzcne was used as the medium for both the diazotization and dediazoniation steps. 

Benzyne, generated by the diazotization of anthranilic acid with isoamyl nitrite, is added to Gd Cs2 forming two isolable isomers of mono-adducts. Electrochemical measurements disclosed that the electronic structure of pristine Gd Cs2 has changed dramatically. Because of the high reactivity of benzyne, multiple adducts are not avoidable, even at lower temperatures [146]. 

The diazotization of anthranilic acid, a classic route to benzyne, when carried out in the presence of vinyl acetate, vinyl ethers or 1,1-dichloroethylene gives the expected benzocyclobutenes in about 40% yield. Despite the rather moderate yields this method represents a convenient route to multigram quantities of the parent compounds, benzocyclobutenol and benzocyclobutenone. The latter is easily converted to benzocyclobutene-1,2-dione. The diazotization sequence applied to 2-amino-3,6-dimeth-oxybenzoic acid and 1,1-dichloroethylene results in a 80% yield of 3, imethoxycyclobuten-l-one. Trapping of benzynes with other ethylene derivatives, and especially more substituted alkenes, has given generally poorer, variable results. ... 

A solution of 13.7 g. (0.1 mole) of anthranilic acid in dilute sulfuric acid is diazotized in customary fashion [Org. Syntheses Coll. Vol. 1, 374 (1941)] at 0-10° with an aqueous solution of 7.5 g. (0.11 mole) of sodium nitrite. The resulting clear solution is added with agitation to a solution of 25 g. (0.15 mole) of potassium iodide in dilute sulfuric acid. The mixture is heated to boiling for a few minutes, and then cooled, the o-iodobenzoic acid is removed by filtration. Recrystallization from hot water gives a product melting at 162°. The yield is nearly quantitative. 

Benzenediazonium-2-carboxylate and its substituted derivatives have been prepared by diazotization of anthranilic acids in the presence of hydrochloric acid followed by dehydrochlorination of the resultant diazonium carboxylate hydrochlorides with silver oxide. 

The synthesis starts from anthranilic acid which is first diazotized and the selenium introduced by treatment of the diazonium salt with Li2Sc2, obtained from elemental lithium and selenium in an aptotic medium <1993LA1239> or better with Na2Se2, prepared in advance by the reaction of selenium powder, 100% hydrazine hydrate, and sodium... 

There are only a few synthetic approaches toward these polycyclic systems. The coupling product from diazotized anthranilic acid and 2-hydroxy-1,4-naphthoquinone is transformed into 372 by heating with acetic anhydride (83IJC(B)95). The same quinone reacts with citral and, depending on the reaction conditions, several products are formed. In a triethylamine-catalyzed reaction, the angular quinones 373 and 374 are formed, whereas acid-catalyzed condensation gives the linear compound 375 (82SC195 ... 

JCS(P1)659). For condensation products with other aldehydes, a linear pentacyclic structure was proposed, but not proved (1894JCS76). 2-Chloro-or 2,5-dichloro-l,4-benzoquinones are arylated with diazotized anthranilic acid the reaction is postulated to proceed via a pentacyclic quinone 376, which was isolated in low yield (59JCS3250). 

Dimethoxyethane is preferred as solvent for the generation of benzyne by aprotic diazotization of anthranilic acid with isoamyl nitrite." ... 

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