Diaryl-2-diazonium salts

Unsymmetrical diaryls may be prepared by treating an aryl diazonium salt solution with sodium hydroxide or sodium acetate in the presence of a liquid aromatic compound. Thus 2-chlorodiphenyl is readily formed from o-chloro phenyl diazonium chloride and sodium hydroxide solution (or sodium acetate solution) in the presence of benzene ... 

The reactions of arenediazonium ions with 7V-alkyl- or 7V-arylhydroxylamines were investigated by Bamberger (1920b, and earlier papers). Mitsuhashi et al. (1965) showed that the l,3-diaryl-3-hydroxytriazenes are tautomeric with 1,3-diaryltriazene-3-oxides (Scheme 6-16). Oxidation of 1,3-diaryltriazenes with peroxybenzoic acid in ether yields the same product as that from diazonium salts and TV-arylhydroxyl-amine. The infrared spectrum of the product obtained by coupling diazotized relabeled aniline with A/-phenylhydroxylamine indicates that the diaryltriazene-oxide is the preponderant tautomer. 

Diazonium salts react with bis(methylsulfonyl) methane (107) (X = S02CH3) to yield a 1,3-diaryl tetrazolinone (111). The reaction proceeds through an azo (108) and a tetrazene (109) intermediate, followed by hydrolysis under the alkaline conditions of the reaction to the carbonyl compound (110). An unexplained oxidation leads to the 1,3-diaryl tetrazolinone (111) either directly or through the intermediate 110a (Scheme 15).18,35 A similar reaction occurs between a diazonium salt and the potassium salt of phenyl hydrazonomethane disulfonic acid (Scheme 15).175... 

The synthesis of 4-amino-3,5-diaryl-l,2,4-triazoles is well documented but deamination using sodium nitrite in aqueous nitric acid typically gives low yields and is restricted in its scope. A more efficient method of deamination using aqueous hypophophorous acid has been reported the intermediate diazonium salt formed in this reaction is reduced quickly within the reaction mixture, leading to high yields (Equation 29 and Table 10) <2002JHC93>. 

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],... 

The profitable conversion of thiouronium salts into dialkyl thioethers (see Section 4.1) is less successful for synthesis of diaryl thioethers. For example, l-chloro-4-nitrobenzene reacts with bis-thiouronium salts of the type (H2N)2CS(CH2) SC(NH2)2+ under soliddiquid and liquidrliquid conditions to produce the desired bis-thioethers, ArS(CH2) SAr, (20-35%), together with the diaryl sulphide, Ar2S (5-15%). Higher yields of the diaryl sulphide are observed under liquiddiquid conditions whereas, under solidiliquid conditions, the diaryl disulphide, (ArS)2, (20%) is also formed [56], Diaryl disulphides are the sole products (>65%) from the stoichiometric reaction of aryl diazonium salts with benzyltriethylammonium tetrathiomolybdate [57],... 

Gomberg-Bachmann-Hey reaction org chem Production of diaryl compounds by adding alkali to a mixture of a diazonium salt and a liquid aromatic hydrocarbon or a derivative. gom,berk bak,man hT re.ak shan )... 

Base-promoted radical coupling between an aryl diazonium salt and an arene to form a diaryl compound. 

The derivatives (54 Ar = Ph, />S03HC6H4) have been obtained as crystalline products in good yield by diazotization of the amines (52) (Equation (1)). The intermediate diazonium salts could not be isolated <79ZN(B)275, 80MI 714-01). Using a similar approach, but starting from the amines (53), 2,5-diaryl derivatives have been obtained <93MI 714-01). 

Arenediazonium chlorides react with elemental tellurium to form diaryl tellurium dichlorides in yields not exceeding 40%. The diazonium salts were prepared from aromatic amines and amyl nitrite14. 

Arylhydrazinc, tellurium dioxide, and lithium chloride refluxed in acetic acid yielded diaryl tellurium dichlorides. It is likely that tellurium dioxide oxidizes the arylhydrazines to diazonium salts. The reduced tellurium formed then reacts with the diazonium salt4. 

N-Amino groups are replaced by hydrogen on treatment with phosphorus trichloride (l,2,4-triazole-4-acylimines are converted into triazoles) or with nitrous acid (e.g., 824 825). 4-Amino-3,5-diaryl-l,2,4-triazoles are deaminated efficiently by reduction of the diazonium salt with aqueous hypophosphorous acid <2002JHC93>. AAAlkylaminoazoles form stable N-nitroso compounds, normally existing as a mixture of E- and Z-rotamers. 

Base-catalyzed reaction between an aryl diazonium salt and an aromatic hydrocarbon (or aromatic heterocycle) to form a diaryl compound (or aryl-substituted heterocycle) involves radical coupling reaction, as shown in Scheme 2.49. 

The thiol (SH) group is introduced by reaction with potassium ethyl xanthate followed by acid hydrolysis. The phenylsulfanyl (phenylthio, SPh) group results from reaction with benzenethiolate ion. Sodium disulfide, Na2S2, yields diaryl disulfides. The arsonic acid group is introduced using Bart s reaction, in which a diazonium salt is reacted with sodium arsenite in the presence of a Cu(II) salt (Scheme 8.23). 

Gomberg-Bachmann reaction. Formation of diaryl compounds from aryl diazonium salts and aromatic compounds in the presence of alkali. 

Phenol readily couples with diazonium salts to yield coloured compounds. The latter can be nsed for the photometric detection of phenol as in the case of diazotized 4-nitroaniline. Sahcylic acid (2-hydroxybenzoic acid) can be prodnced by the Kolbe-Schmitt reaction (stndied by the density functional method ) from sodinm phenolate and carbon dioxide, whereas potassium phenolate gives the para compound. Alkylation and acylation of phenol can be carried out with aluminium chloride as catalyst methyl groups can also be introduced by the Mannich reaction. Diaryl ethers can only be produced under extreme conditions. 

In the reaction between a diazo group and dichlorosulphine, there is evidence for a 1,3-dipolar addition to give (after loss of nitrogen) an episulphoxide from which an 5-ring carbon bond is formed. A C—C bond is formed when a diazonium salt of a diaryl thioether is heated with copper powder (a Pschorr reaction) in this example (see above equation), the product is a [I]benzothi-eno[2,3-6]pyridine (793, X = S, 18% yield). 

Sulfur transfer. The reaction with arenediazonium salts leads to diaryl disulfides. Interestingly, l,l -binaphthalene-2,2 -dithiol is the only product (61% yield) in the reaction with the bis-diazonium salt derived from l,r-binaphthyl-2,2 -diamine. 

The synthesis of 1,4-diaryl-1,4-dihydro-1,2,4,5-tetrazines (255) can be achieved in good yield by the reaction between aryl-diazonium salts and phenacylidene dimethylsulphurane (254)... 

Diaryl sulphides may be prepared by the reaction of arenediazonium tetrafluoroborates with aryl thiolates. The experimental procedure involves the addition of a solution of the diazonium salt in DMSO to the stirred thiolate.245... 

---