Benzenediazonium chloride preparation

To a mixture of 19 g methanesulfonamide, 16 g NaOH, and 400 mL water was added slowly a benzenediazonium chloride prepared by mixing a solution of 18.6 g aniline, 60 mL of concentrated HCl and 100 mL water with 14 g NaN02 in 60 mL water. The yellow solid that first appeared soon decomposed, and the phenylazide thereby produced was extracted with ether and purified in the usual way, in amount of 19.0 g. 

Meanwhile, during the cooling of the cuprous chloride solution, prepare a solution of benzenediazonium chloride by dissolving 20 ml. (20-5 g.) of aniline in a mixture of 50 ml. of concentrated hydrochloric acid and 50 ml. of water, and after cooling to 5°, adding slowly a solution of 17 g. of sodium nitrite in 40 ml. of water. Observe carefully the general conditions for diazotisation given in the preparation of iodobenzene (p. 184). 

Diphenylbutadiene has been obtained from phenylacetic acid and cinnamaldehyde with lead oxide, by the dehydrogenation of l,4-diphenyl-2-butene with butyllithium, and by the coupling reaction of benzenediazonium chloride and cinnamyl-ideneacetic acid." The present method gives better yields than those previously reported, is adaptable to the preparation of a variety of substituted bistyryls, and is relatively easy to carry out. 

Incidentally, 31 contributes more to the hybrid than 32, as shown by bond-distance measurements. In benzenediazonium chloride, the C—N distance is 1.42 A, and the N—N distance 1.08 A, which values lit more closely to a single and a triple bond than to two double bonds (see Table 1.5). Even aromatic diazonium salts are stable only at low temperatures, usually only below 5°C, though more stable ones, such as the diazonium salt obtained from sulfanilic acid, are stable up to 10 or 15°C. Diazonium salts are usually prepared in aqueous solution and used without isolation, though it is possible to prepare solid diazonium salts if desired (see 13-20). The stability of aryl diazonium salts can be increased by crown ether complexion. ... 

Dining preparation of thiophenol by addition of a cold solution of potassium O-methyldithiocarbonate to a cold solution of benzenediazonium chloride, a violent explosion accompanied by an orange flash occurred [1], This was attributed to the formation and decomposition of bis(benzenediazo) disulfide. A preparation in which the diazonium solution was added to the xanthate solution proceeded smoothly [2],... 

Several l,2,3-triazolo[4,5- ]pyridines have been prepared by Al-Mousawi and Moustafa by treatment of the corresponding triazole with either malononitrile (Equation 17) or benzenediazonium chloride (Equation 18), respectively <2007BJ012>. 

Thiazolyl)pyrimido[4,5-i/]pyridazines have been prepared by utilizing the reaction of the active methylene compound 46 with benzenediazonium chloride (Scheme 24) to give a hydrazone, which cyclizes spontaneously <1999JPR147>. A further approach described recently <2002HAC108> involves reaction of the malononitrile derivative 47 with a further equivalent of malononitrile, forming a pyrimidine with a suitably disposed hydrazine, which cyclizes on exposure to strong base (Scheme 25). 

The preparation of 2-phenylazo-l,3-indandione (m.p. 192°-193°C) by condensation of benzenediazonium chloride with 1,3-indandione is an example of azo formation from an active methylene compound [24]. With an active methinyl compound such as the methyl 1,3-indandione-2-carboxylate, the corresponding 2-arylazo-l,3-indandione-2-carboxylate ester has been prepared [25] (see Eq. 8). 

Heterocyclic azo couplers have also featured prominently in disperse dye chemistry, especially in the production of yellows. Cl Disperse Yellow I (B-71MI11202) is in fact an azo dye prepared from benzenediazonium chloride and l-phenyl-3-methyl-5-pyrazolone, and pyrazolone couplers continue to appear in patents. However, the most important recent development has been the introduction of 2,6-dihydroxypyridine couplers in azo dyes such as (54). Although the couplers had been disclosed some time ago, their development by... 

To prepare the solid benzenediazonium chloride or sulphate, the reaction is conducted in the absence of water as far as possible. The source of nitrous acid is one of its organic esters (e.g. pentyl nitrite) and a solution of hydrogen chloride gas in absolute ethanol upon the addition of ether only the diazonium salt is precipitated as a crystalline solid. 

Attention has previously been drawn (Section 6.7.1, p. 922) to the fact that unless an excess of hydrochloric (or mineral) acid is used in the diazotisation process, coupling occurs between the diazonium salt and the amino group in the amine to give diazoamino compounds. Thus benzenediazonium chloride and aniline yield diazoaminobenzene. This substance may be conveniently prepared by dissolving two equivalents of aniline in three equivalents of hydrochloric acid, and adding one equivalent of sodium nitrite in aqueous solution followed by two equivalents of sodium acetate (Expt 6.86). 

See Hydrogen trisulfide Benzenediazonium chloride 4-Chloro-2-methylbenzenediazonium salts, 2715 Hydrogen trisulfide Benzenediazonium chloride, 4479 3-Quinolinethiol preparation from the diazonium salt, 3116 3-Toluenediazonium salts, Ammonium sulfide, or Hydrogen sulfide, 2770 3-Toluenediazonium salts, Potassium O-ethyl dithiocarbonate, 2770... 

Sodium carbonate is often employed as a buffering agent in the ordinary Bart reaction. In this way phenylarsonic acid has been prepared in yields ranging from 50-60% 7 to as high as 86% 8 as compared with yields of 40-50% by the original process. The yield from benzenediazonium chloride and sodium arsenite is greatly influenced by the concentration of the arsenite, the speed of reaction, and especially by the pH of the solution (which should remain constant). All compounds, like sodium carbonate, which play the role of buffer, tend to increase the yield.9... 

Concurrently with the preparation of the sodium arsenite solution, a solution of benzenediazonium chloride is prepared. To a well stirred mixture of 186 g. (2.0 moles) of technical aniline, 400 cc. (4.8 moles) of concentrated hydrochloric acid (sp. gr. 1.19), 1 1. of water, and enough crushed ice to make a volume of about 3 1. is added slowly a solution of 145 g. (2.0 moles) of 95 per cent sodium nitrite in 500 cc. of water. This requires about thirty to forty minutes. 

Various 2-substituted l,3,4-thiadiazoline-5-thiones can be prepared in good yield by the reaction of amidrazones with CS2 in ethanol at room temperature (Scheme 21a) (70CPB1696). 4-Aryl-2-benzoyl-5-imino-A2-l,3,4-thiadiazolines are prepared from activated thiocyanates and benzenediazonium chloride, presumably via a hydrazone (Scheme 21b) (75TL163). 2-Thio- and 2-amino-l,3,4-thiadiazoles carrying a carbamate in the 5-position are obtained in one step by the reaction of a dithioimidate with a hydrazide. The yields are quite high (Scheme 22a) (80ZC413). 

Phenylazo-1,2,4-triazole were prepared from benzenediazonium chloride and 1,2,4-triazole <07SC1977>. 5-Aryltriazole acyclonucleosides 134 with various aromatic groups on the triazole ring were synthesized from precursor 133 via the Suzuki coupling reaction in aqueous solution and promoted by microwave irradiation <07TL2389>. 1-Methyl-1,2,4-triazole 135 participated in a palladium-catalyzed C-H arylation reaction with 3,5-dimethoxychlorobenzene 136 to give coupled product 137 <07OL1449>. 

Diazotization in organic solvents allows solid diazonium salts to be isolated. Diazotization can be carried out using an ester of nitrous acid, such as pentyl nitrite, in a solvent such as acetic acid or methanol. A procedure has also been described for isolating diazonium tetrafluoroborates, in excellent yield, by carrying out the diazotization with boron trifluoride etherate and f-butyl nitrite in ether or dichlorometh-ane at low temperature. Another method for the preparation of a variety of diazonium salts in a nonaqueous medium makes use of the chemistry of bis(trimethylsilyl)amines (8). These compounds react in dichloromethane with nitrosyl chloride and other nitrosating agents which are generated in situ. Thus, benzenediazonium chloride was isolated (96%) from bis(trimethylsilyl)aniline. 

In one of a number of preparations, a batch (about 960 g.) of the addition compound from benzenediazonium chloride was air dried and placed in a large bottle with a screw cap. About four... 

The preparation of arylazo derivatives from hydroxypyrazines has been described in Section VI.6E and from l,4,6-trimethyl-3-methylene-2-oxo-l,2,3,4-tetrahydro-pyrazine to give l,4,6-trimethyl-2-oxo-3-phenykzomethylene-l,23,4-tetrahydro-pyrazine in Section VI.9B. In addition to these reactions Princivalle (1122) reports that 2reacted with benzenediazonium chloride and p-toluenediazonium chloride by elimination of the carboxy group para to the hydroxy group and coupling to form 2-hydroxy-3,6-dimethyl-5-phenyl-azo(and p-tolueneazo)pyrazines, respectively (1122), identical to those prepared from 3-hydroxy-2,5 -dimethylpyrazine. 

The reaction of phenylhydrazine with oxysucrose was found to be similar to that described for oxidized monosaccharide derivatives above, as only two molecules of the base reacted with the four potential aldehyde groups the product was assigned structure (89). Mester found that this derivative forms an amorphous bis(diphenylformazan) with benzenediazonium chloride, and so he assigned structure (90) to it. Acetylation of the formazan gave an amorphous product, identical with the formazan prepared from... 

A) Preparation of lodobenzene (Sm.). The solution prepared in Experiment 53 (C), is used. Place in a 150-ml beaker 15 ml (0.015 moles) of the cold benzenediazonium chloride solution, and add with stirring a solution of 3.0 g of potassium iodide in 20 ml of water. Allow to stand in the cold for 30 minutes and then add, with stirring, 3 ml of concentrated hydrochloric acid. Warm to 50° until the evolution of gas ceases. Make the solution alkaline with sodium hydroxide (5 ml 6 Af) and allow the liquid to settle out. Pour out most of the upper aqueous layer and retain all the oil that settles to the bottom, with about 5 ml of the aqueous layer. The preparation may be discontinued at this point until the next laboratory period. 

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