Aryldiazonium chlorides, reaction with

Schmidt11 suggested that the coupling reaction be carried out in neutral solution and without a catalyst. The best yields were obtained when the aryldiazonium chloride reacted with dipotassium arsenite in aqueous solution. 

Arylpentazoles can be prepared by adding an aqueous solution of azide to a mixture of an aryldiazonium chloride, aqueous methanol, and petroleum ether at —40 to —20° with stirring. The pure aryl-pentazole (see Table I) crystallizes from the two-phase reaction mixture the inorganic impurities remain in the aqueous methanol and the organic impurities in the petroleum ether. 

Reaction of melatonin with various aryldiazonium chlorides in ethanolic sodium acetate solution afforded arylazo-melatonin derivatives. Reactions of these products with either malonitrile or ethyl cyanoacetate formed the corresponding ary lam inotriazino[4,3-/z indole scaffolds 60-63 <2005BMC1847>. 

Analogous consideration of aryldiazonium salts and sulfur dioxide reaction with a-nitro olefins in the presence of cupric chloride gave rise to a conclusion that the process also includes the electron-transfer step and develops according to anion-radical mechanism (Bilaya et al. 2004). The reaction eventually leads to the formation of p-arylsulfonyl a-nitroethanes. 

Reactions of phenylhydrazine with 6-bromo-6,7,8,9-tetrahydro (128) and 6,6-dibromo-6,7,8,9-tetrahydro- and -1,2,3,4,6,7,8,9-octahydro-l l//-pyrido-[2,1 -6]quinazolin-l Tones (129), and reactions of aryldiazonium chlorides with 6,7,8,9-tetrahydro- and l,2,3,4,6,7,8,9-octahydro-ll//-pyrido-[2,1 -6]quinazolin-l 1 ones (130 and their 6-substituted derivatives (131-133) yielded 6-arylhydrazono-6,7,8,9-tetrahydro- and 1,2,3,4,6,7,8,9-octahy-dro-ll//-pyrido[2,l-6]quinazolin-ll-ones (134) (Scheme 4) (84JHC1301 87JHC1045). 

Arenesulfonyl chlorides.1 Aryldiazonium chlorides are converted into arenesul-I onyl chlorides by reaction with S02 and CuCl. Yields from the corresponding aniline arc 30 90%, being highest with anilines substituted with electron-withdrawing substituents. 

Reaction of aryldiazonium chlorides with sodium 6,9-dimethyl-6,7,8,9-tetrahydro- and 1,6-dimethyl-l, 6,7,8-tetrahydro-4-oxo-4//-pyrido[l, 2-u]pyrimidine-3-carboxylates 582 and 17 in water in the presence of sodium acetate at 5°C gave 9-(aryldiazo) derivatives 583 and 584 (83JMC1126). 

The free radical arylation of thiazole (391) has been performed either by the Gomberg-Bachmann (392) decomposition of aryldiazonium chlorides (119,393), by the thermal decomposition of benzoyl peroxide (394-397) or N-nitrosoacetanilide (398), or by the photolysis of benzoyl peroxide or iodobenzene (398). The three monophenylthiazoles are obtained in the practically constant proportions 2-phenyl, 60% 5-phenyl, 30% 4-phenyl, 10%, giving the order, 2>5>4, of decreasing reactivity of the three positions of thiazole toward phenyl radicals (398). Competition reactions with nitrobenzene (397) gave an estimation of the globed reactivity of thiazole relative to benzene of 0.75 with the partial rate factors f2 = 2.2, /s=1.9, /4 = 0.5. When the thermolysis of benzoyl peroxide is performed in acetic acid solution, the substrate in reaction is the conjugate acid of thiazole the global reactivity is enhanced to 1.25,... 

Aryldiazonium tetrahaloborates, ArN=NBX4, In the Schiemann reaction, an arylamine is diazotized in aqueous hydrochloric acid solution, and the solution or suspension of aryldiazonium chloride is treated with a solution of fluoroboric acid prepared by dissolving boric acid with cooling to 20-25° in commercial 50-60% hydrofluoric acid contained in a reaction flask coated with wax or lined with copper, lead, or silver. The aryldiazonium tetrafluoroborate is collected, dried, and decomposed by pyrolysis. Examples are ... 

Amino-5-imino-3-pyrazolidinones have been synthesized by reduction of the corresponding oximes.644,1339 Such amines form ureas and thioureas by reaction with potassium cyanate in acid solution and with phenyl isothiocyanate.644 4-Arylimino-5-imino-3-pyrazolidinones have been prepared by reaction of the 5-imino-3-pyrazolidinones with p-amino-A.-AT-diethylaniline in the presence of silver salts as oxidizing agents (eq. 172).244,519,1255,1538 4-Arylazo-5-imino-3-pyrazolidinones have most frequently been prepared by reaction of 5-imino-3-pyrazoli-dinones with aryldiazonium chlorides, as is usual for the preparation of similar compounds.591,594,920,1087,1255,1339,1539,1649 One such compound has been prepared by the Curtius rearrangement of the corresponding 4-arylazo azide.594... 

It has been shown (98JFC(92)101) that the reaction of hydrazine in Et20 and hydroxylamine hydrochlorides in CH3OH in the presence of NaOAc with ethyl-2-(/wa-methoxyphenyl)-hydrazone-4,4,4-trifluoro-2,3-dioxobutanoate 57, obtained by reactions of 1,3-ketoesters with aryldiazonium chloride, gives 3-nonafluorobutyl-4(/wa-methoxyphenyl)hydrazonepyrazolin-5-one 58 and 3-fluoromethyl-4(/wa-methoxyphenyl)hydrazonepyrazolin-5-one 59, respectively (98JFC(92)101) (Scheme 52). 

Today, the GBH reactions are performed by using aryldiazonium tetrafluoroborate salts. An aromatic amine is diazotized at about -10 to 0 C in the presence of at least 3 equivalents of concentrated hydrochloric acid by adding the solution of sodium nitrite [61]. To the aryldiazonium chloride, 50% aqueous solution of tetrafluoroboric acid is added with additional cooling to precipitate the corresponding aryldiazonium... 

This reaction is the most simple method for synthesis of these structures beside several recent methods based on cross-coupling reactions with different organometallic reagents. The starting materials are very inexpensive and easily available, whereas an excess of arene can be regenerated by distillation of the filtrate after the separation of potassium tetrafluoroborate. This can be also reused as a precipitation reagent for preparation of the parent aryldiazonium tetrafluoroborate from the diazonium chloride... 

To a concentrated hydrochloric acid (37%, 250 ml, 3 mol) precooled to -5 C, a liquid arylamine (1 mol) was added dropwise, or in several portions (for solids) during 15 min. The mixture was stirred at -5 °C for an additional 45 min (solid amines has to be grounded to fine powder). A solution of sodium nitrite (69.00 g, 1 mol, 1 eq.) in distilled water (250 ml) was added dropwise at -10 to -5 C during 1 h. The reaction mixture was stirred at -5 °C for an additional 1 (-2) h, until the TLC analysis shows the disappearance of the starting amine. To the obtained clear yellow solution of aryldiazonium chloride, 48% aqueous solution of tetrafluoroboric acid (150 ml, 100.80 g, 1.15 mol, 1.15 cq.) was added dropwise at -5 °C during 15 minutes. The mixture was stirred at -10 °C for 30 minutes, and the crystals were collected by filtration, washed with precooled (+5 °C) water (3x20 ml), and dried at 30 C in high vacuum for 20 h. The pure aryldiazonium tetrafluoroborates were obtained in 60-90% yields. 

The reaction of thiiran with aryldiazonium chlorides in the presence of copper chloride yields jS-chloroethyl aryl sulphides and diaryl disulphides via radical intermediates (Scheme 4). Treatment of thiirans with sodium methyl xanthate... 

Menger, F.M., Williams, D.Y, Underwood, A.L., Anacker, E.W. Effect of counterion geometry on cationic micelles. /. Colloid Interface Sci. 1982,90(2), 546-548. Loughlin, J.A., Romsted, L.S. A new method for estimating counter-ion selectivity of cationic association colloid trapping of interfacial chloride and bromide counterions by reaction with micellar bound aryldiazonium salts. Colloids Surf. 1990, 48(1-3), 123-137. 

As mentioned in the discussion of the reaction mechanism for this transformation, the active species is a dicoordinate Pd(0) complex, and it is unclear whether an associative or a dissociative process is operative for oxidative addition. In this context, different NHC complexes containing only one carbene ligand have been tested in the Mizoroki-Heck reaction. The most successful are those prepared by Beller, which were able to perform the Mizoroki-Heck reaction of non-activated aryl chlorides with moderate to good yields in ionic liquids (Scheme 6.13). The same compounds have also been applied to the Mizoroki-Heck reaction of aryldiazonium... 

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