Diazotisation of anthranilic acid

A) Diazotisation of Anthranilic Acid, Dissolve 20 g. of anthranilic acid in a solution of 7 5 g. of anhydrous sodium carbonate in 200 ml. of water contained in a 400 ml. beaker, (The mixture may be warmed very gently with stirring to obtain a solution more rapidly, and then cooled.) Add slowly 12 g. of sodium nitrite and cool the stirred solution below 10 , Pour this cold solution slowly on to a vigorously stirred mixture of 40 ml, of concentrated hydrochloric acid and 120 g. of crushed ice in a 600 ml. beaker. 

Several of these internal diazonium salts, prepared by diazotisation of anthranilic acids, are explosive in the solid state, or react violently with various materials. Individually indexed compounds (including analogous sulfonates) are Benzenediazonium-2-carboxylate, 2659 Benzenediazonium-3 or 4-carboxylate, 2661... 

Diazotisation of anthranilic acid and immediate reduction of the diazo group is a very simple route to indazolin-3-one. Hydrolysis of the amide unit of isatin, then diazotisation and reduction produces indazole-3-carboxyhc acid adding the diazonium salt solution to the reducing mixture minimizes the formation of byproduct indazolin-3-ones. ... 

Diazotisation. Dissolve 0 2 g. of anthranilic acid in about 4 ml. of dil. HCl and cool in ice-water. To this solution, add slowly about I ml. of cold 20% sodium nitrite. solution and divide the cold diazonium solution thus prepared into two portions A and B. 

The same compound has been obtained by a number of other research groups, using a number of different methods of generating tetrafluoro-benzyne. These include the loss of magnesium halide from pentafluorophenylmagnesium halides 44 46>, the loss of lithium fluoride from penta-fluorophenyl-lithium 47>48), and the aprotic diazotisation of tetrafluoro-anthranilic acid 49>. 

Another surprising feature appears in the reactions of certain alkyl-benzenes with tetrabromo- and tetraiodo-benzyne generated by the aprotic diazotisation of the corresponding anthranilic acids S9K While only one product (41, X = Br or I, R = H or Me) was obtained in the reactions with benzene or -xylene, three products, (42, X = Br or I, R = Me, Pr1, or But), (43, X = Br or I, R = Me, Pr1, or But) and a naphthalene derivative a> were obtained in reactions with toluene, cumene (isopropylbenzene), and f-butylbenzene. 

A very convincing demonstration of the existence of benzyne by physical methods involves the introduction into the heated inlet of a mass spectrometer of the zwitterion ion (106), a salt of diazotised o-aminobenzoic(anthranilic) acid. The mass spectrum is found to be a very simple one exhibiting m/e peaks at 28, 44, 76 and 152 ... 

Interaction of substituted arenediazonium salts with potassium O. O-diphenylphosphorodithioates gave a series of solid diazonium salts which decomposed explosively when heated dry [10], The unique failure of diazotised anthranilic acid solutions to produce any explosive sulfide derivatives under a variety of conditions has been investigated and discussed [6]. Preparation of diaryl sulfides from interaction of diazonium and thiophenoxide salts led to violent explosions, attributed to presence of some arenediazo sulfide during subsequent distillation of the diaryl sulfides. Precautions are detailed [11]. A safe method of preparation of diaryl sulfides from diazonium tetralluoroborates and sodium benzenethiolate in DMF is now available [12],... 

During interaction of the diazonium chloride, and the o-ethyl dithiocarbonate ( xan-thate ) solutions, care must be taken to ensure that the intermediate diazonium dithiocarbonate decomposes to 2-thiocresol as fast as it is formed [1]. This can be assured by presence of a trace of nickel in the solution to effect immediate catalytic decomposition. When the 2 solutions were mixed cold and then heated to effect decomposition, a violent explosion occurred [2]. Caution The experiments claimed to show catalysis by nickel appear to have been performed on diazotised anthranilic acid which is the only benzenediazonium system never known to give explosive intermediates with sulfur nucleophiles [3]. 

Many other industrial methods are now employed e.g. one starts (22) with anthranilic acid which is diazotised and treated with liquid sulfur dioxide in presence of copper as catalyst. The sulphinic acid derivative thereby obtained is treated with chlorine in alkaline solution and sulfonyl chloride so obtained is treated with ammonia and heated. 

Anthranilic acid (150 grams) in 2000 c.c. of water and 225 c.c. of concentrated hydrochloric acid is diazotised with 80 ams of sodium nitrite, keeping the temperature below 5° C. An arsenite solution is prepared... 

Diazotised anthranilic acid is condensed with an alkaline solution of o-carboxyphenylarsenoxide and the product recrystallised from methyl alcohol and finally from water. It melts at 256° C., and when reduced gives o-o -dicarboxydiphenylarsenious anhydride, M.pt. 251° to 255° C. The latter compound is insoluble in ether, benzene, chloroform, or carbon tetrachloride, but dissolves in methyl alcohol. When its solution in this solvent is treated with hydrogen chloride it gives o-o -dicarbomethotnydiiphenylehloroarsine, M.pt. 184° C. ... 

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