Iodobenzene 4-nitro

Bromobenzene, iodobenzene and benzyl chloride behave somewhat similarly. The />-nitro-derivatives of the first two compounds frequently crystallise out even before pouring into water p-nitrobenzyl chloride usually remains as an oil for several minutes before solidifying. 

Several approaches to the 1,2,3-triazole core have been published in 2000. Iodobenzene diacetate-mediated oxidation of hydrazones 152 led to fused 1,2,3-triazoloheterocycles 153 <00SC417>. Treatment of oxazolone 154 with iso-pentyl nitrite in the presence of acetic acid gave 1,2,3-triazole 155, a precursor to 3-(W-l,2,3-triazolyl)-substituted a,P-unsaturated a amino acid derivatives <00SC2863>. Aroyl-substituted ketene aminals 156 reacted with aryl azides to provide polysubstituted 1,23-triazoles 157 <00HC387>. 2-Aryl-2T/,4/f-imidazo[43-d][l,2,3]triazoles 159 were prepared from the reaction of triethyl AM-ethyl-2-methyl-4-nitro-l//-imidazol-5-yl phosphoramidate (158) with aryl isocyanates <00TL9889>. 

Lin and Zhang reported the synthesis of l-hydroxy-3-methylcarbazole (23) starting from the nitro derivative 625 (578). This synthesis uses a Buchwald-Hartwig amination for the synthesis of the diphenylamine 628. After protection of the hydroxy group in the nitrophenol 625 as a benzyl ether, the nitro group was reduced to the corresponding amino derivative 627. Amination of 627 with iodobenzene under Buchwald-Hartwig conditions afforded the diarylamine 628. Palladium(ll)-mediated cyclization of 628 led to the carbazole derivative 629, albeit in low... 

Iodoaniline has been prepared by the reduction of -nitro-iodobenzene 1 by the hydrolysis of -iodoacetanilide formed by the action of iodine monochloride on acetanilide 2 and by the direct iodination of aniline.3 The method described here is an adaptation of the procedure used by Wheeler/ and by Hann and Berliner 5 for the iodination of the toluidines. 

Iodobenzene prepared by this procedure may contain traces of nitro compounds. The test for these is to reduce a sample with stannous chloride (or tin) and hydrochloric acid, and treat the resulting acid solution in the cold with a solution of sodium nitrite. If a phenolic odor is obtained on boiling the solution, nitro compounds are still present. A more delicate test can be made by adding the reduced solution, after treatment with sodium nitrite, to an alkaline solution of /3-naphthol an azo dye is formed if nitro compounds were originally present. 

Much research has been carried out on the Ugand-free palladium-catalysed Suzuki reaction. Already in 1989, Beletskaya reported a Ugand-free Suzuki reaction in water, between iodobenzoates and phenylboronic acid using Pd(OAc)2 as catalyst [81]. Later, Novak took up the quest to develop a highly active catalyst for the Suzuki reaction and since he noted that this reaction suffers from phosphine inhibition he decided to test three Ugand-free palladium catalyst precursors Pd(OAc)2, [(Ti -CsHsjPd PdCl]2, and Pd2(dba)3.QH6 [82]. All three catalysts performed well in the Suzuki reaction between 4-nitro-iodobenzene and phenylboronic acid. In the reaction with 4-nitro-bromobenzene the first and last catalyst were clearly superior with yields of 96-98% (Scheme 10.7). Novak suggests that... 

Methods F and G are ligandless palladium-catalysed and therefore dramatically sensitive to the presence of an oxygen [28]. Beside aryl bromides, the Pd(OAc)2 or Pd(SEt2)Cl2-catalysed SM reactions in A,iV-dimethylformamide were effectively conducted with aryl chlorides [29]. When appropriate precautions were taken, the SM cross-coupling reaction of phenylboronic acid (260) with 4-nitro-bromobenzene (168) or 4-nitro-iodobenzene (225) furnished 4-nitrobiphenyI (224) with a quantitative yield within 0.75 or 2.5 h. Scheme 16. 

Among the intermolecular arylations, specially useful are those with thiophenes and furans. The latter electron-rich heterocycles bearing an electron-withdrawing group readily undergo the arylation with aryl iodides and bromides to give the respective biaryls in good to excellent yields. In this fashion, 4-nitro-iodobenzene (225) reacts with furfural (478) to produce the biaryl 479 in 88% yield, respectively. Scheme 28. 

Buchwald s binaphthyl 631 was proved as more effective ligand, providing good to high enantioselectivity (70-92% e.e.)- Thus 2-phenylnaphthylboronic acid (635) was reacted with 2-nitro-iodobenzene (18) to give the respective biaryl 636 in 86% yield and 73% e.e. [38], Scheme 18. 

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