硝普钠与苯肼的反应

有氧存在下 ,硝普钠 (Na2 [Fe(CN) 5NO] )与苯肼类化合物在N ,N 二甲基甲酰胺中作用 ,发生脱肼反应 ,生成叠氮苯、苯衍生物、微量的苯胺及偶氮化合物 .对可能的反应机理进行了讨论     

Transition-Metal-Free Synthesis of Unsymmetrical Diaryl Tellurides via SH2 Reaction of Aryl Radicals on Tellurium

Although diaryl tellurides are parent organotellurium compounds, their synthesis methods, especially for unsymmetrical ones, are limited. This may be due to the instability of diaryl tellurides and their synthesis intermediates under reaction conditions. Radical reactions are known to exhibit excellent functional group selectivity; therefore, we focused on a bimolecular homolytic substitution (S_H2) reaction between the aryl radical and diaryl ditelluride. Aryl radicals are generated from arylhydrazines in air and captured by diaryl ditellurides, resulting in a selective formation of unsymmetrical diaryl tellurides with high yields. The electronic effects of the substituents on both arylhydrazines and diaryl ditellurides on the S_H2 reaction of tellurium are also discussed in detail.     

Asymmetric Synthesis of Tetracyclic Pyrroloindolines and Constrained Tryptamines by a Switchable Cascade Reaction

The interrupted Fischer indole synthesis of arylhydrazines and biocatalytically generated chiral bicyclic imines selectively affords either tetracyclic pyrroloindolines or tricyclic tryptamine analogues depending on the reaction conditions. We demonstrate that the reaction is compatible with a variety of functional groups. The products are obtained in high optical purity and in reasonable to good yield. We present a plausible reaction mechanism to explain the observed reaction outcome depending on the stoichiometry of the acid mediator. To demonstrate the synthetic utility of our method, pharmaceutically relevant examples of both product classes were synthesized in highly efficient reaction sequences, including a phenserine analogue as a potential cholinesterase inhibitor and constrained tryptamine derivatives as selective inhibitors of the 5‐HT₆ serotonin receptor and the TRPV1 ion channel.     

1,3,4,6-Tetracarbonyl Compounds: IV. Reaction of 3,4-Dihydroxy-2,4-hexadiene-1,6-diones with Hydrazine and Arylhydrazines

Reactions of 1,6-disubstituted 3,4-dihydroxy-2,4-hexadiene-1,6-diones with hydrazine hydrate or hydrochloride afforded heterocyclization products, 3,3'-bipyrazoles. The chemoselective reaction of 1,6-diaryl-3,4-dihydroxy-2,4-hexadiene-1,6-diones with arylhydrazines gave rise to 1,1',5,5'-tetraaryl-3,3'-bipyrazoles and 1,5-diaryl-3-aroylacetylpyrazoles. The specific structural features of the pyrazole derivatives obtained are discussed. Some pyrazoles show bacteriostatic and antileukemic activity.     

Tandem hydroformylation/Fischer indole synthesis: a novel and convenient approach to indoles from olefins

[reaction: see text] A novel one-pot synthesis of indole systems via tandem hydroformylation/Fischer indole synthesis starting from olefins and arylhydrazines is described. This tandem procedure leads directly to 3-substituted indoles if unsubstituted phenylhydrazine is used and to 3,5- respectively 3,7-disubstituted indoles if para- or ortho-substituted arylhydrazines are used.     

Convenient synthesis of melatonin analogues: 2- and 3-substituted -N-acetylindolylalkylamines

A new method for the synthesis of 2- and 3-substituted indolylalkylamides, derivatives of melatonin, from arylhydrazines and amidoketones by the Fischer reaction was elaborated. The amidoketones can be easily prepared from cyclic imines by reaction with acylpyridinium chloride. This method is a one-step synchronous creation of the selected alkylamide fragment and the indole core. Variation of the arylhydrazines create the desired substituents in the carbocycle of indolylalkylamides and suitable choice of amidoketone can direct the amidoalkyl chain to the 2- or 3-position of the indole.     

Reaction of 2-arylazo-2, 5-dimethyl-3(2H)-furanones with ammonia. Preparation of β-acetyl-β-(3-amino-2-butenoyl) arylhydrazines.

Ring opening of 2-arylazo-2,5-dimethyl-3(2H)-furanones ($\text{1a–d}$) with ammonia leads to previously unknown β-acetyl-β-(3-amino-2-butenoyl)arylhydrazines ($\text{3a–d}$). The reaction mechanism is discussed.     

Reaction of arylhydrazines with α-formylbutyrolactam derivatives

The Vilsmeier formylation of butyrolactam and of N-phenylbutyrolactam has given their -dimethylaminomethylene derivatives. The reaction of the latter with -substituted arylhydrazines leads to the formation of 1-oxo-1,2,3,4-tetrahydro--carbolines. When unsubstituted phenylhydrazine is used, the occurrence of a competing reaction leading to -aminoethyl derivatives of 5-pyrazolone is also possible. It has been established that the direction of the reaction and the ratio of the products are affected by the substituent at the lactam nitrogen atom.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 56–60, January 1984.     

The Decomposition Reaction of 4‐Acetylsydnones Arylhydrazones

The acidic decomposition of 4‐acetylsydnones arylhydrazones 2 results in the formation of 4‐arylhydrazo‐1,2‐pyrazolin‐5‐ones 3 and 4‐arylamino‐1,2,3‐triazoles 4 , respectively. The reactions of 4‐acetylsydnones 1 with arylhydrazines 5 afford compounds 3 as the only products in the absence of solvent.     

Synthesis and heterocyclization of osazones of carbonyl-substituted glyoxals

Enolates of α-chloro-β-oxoaldehydes react with arylhydrazines in the presence of acetic acid, forming osazones of carbonyl-substituted glyoxals. The same osazones are obtained by the reaction of β-oxo-α-chlorenamines with arylhydrazines. Under conditions of acid catalysis, these osazones undergo intramolecular heterocyclization to the corresponding functionalized pyrazoles. Kazan' State Technological University. Kazan' 420015, Russia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 190–193, February, 1998.     

Synthesis of 1,1-Diacetyl-2-arylhydrazines

The reaction of arylhydrazines 1 with acetic anhydride in the presence of a catalytic amount of 4-(dimethylamino)pyridine leads to 1,1-diacetyl-2-arylhydrazines 4.     

Synthesis of 2-indolylacetic acid derivatives

2-Indolylacetic acid derivatives were synthesized by condensation of diethyl acetonedicarboxylate with α-substituted arylhydrazines under the conditions of the Fischer reaction, and their transformations were studied.     

Air-promoted direct radical arylation of anilines with arylhydrazines

Air-promoted coupling reaction of arylhydrazines and arylamines is developed for the selective synthesis of 2-aminobiaryls. This protocol provides a green, cost-effective, and scale-up method for preparation of 2-aminobiaryls.     

Reaction of 3-benzoyl-1-methyl-4-phenyl-γ-piperidol with arylamines and arylhydrazines. Synthesis of 3-arylamino-1-oxo-1-phenylpropanes and 1,3 diarylpyrazoles and their fragmentation under electron impact

Upon heating in the presence of arylamines 3-benzoyl-4-hydroxy-1-methyl-4-phenylpiperidine decyclizes via a retroaldol type reaction with subsequent transamination of the intermediate Mannich base to give 3-arylamino-1-oxo-1-phenylpropanes. In the case of the use of arylhydrazines this γ-piperidol recyclizes to give 1,3-diarylpyrazoles and their 4,5-dihydro derivatives. The mass spectroscopic behavior of a series of 3-arylamino-substituted 1-phenylpropanones has been studied. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 544–554, April, 2007.     

Indoles

The reaction of arylhydrazines and cyclic semiacetals (α-hydroxytetrahydropyran and α-hydroxytetrahydrofuran) on heating leads, with the evolution of water and ammonia, respectively, to homotryptophols and tryptophols.     

Reaction of arylhydrazines with an α-alkynyl-carbonylic compound: an unexpected hydration reaction

The acid catalyzed reactions of three arylhydrazines with 4-phenyl-3-butynone in order to obtain the corresponding arylhydrazone were realized. The arylhydrazone reaction and an unexpected alkyne hydration reaction product were obtained when diphenylhydrazine was used. This product was identified by spectroscopic methods and X-ray diffractogram. A reaction mechanism is proposed for its formation.     

Regioselective synthesis of trifluoromethylated pyrazoles by selective protection of trifluoromethyl-β-diketones

1,1,1-Trifluoropentane-2,4-dione was selectively protected by treatment with pyrrolidine to give 6 . The reaction of 6 with arylhydrazines gave 5 exclusively. The structural assignment for 5 was confirmed by quenching the dianion of 8 with ethyl trifluoroacetate.     

One-pot synthesis of 2-substituted thieno[3,2-b]indoles from 3-aminothiophene-2-carboxylates through in situ generated 3-aminothiophenes

A convenient protocol for one-pot synthesis of thieno[3,2-b]indoles, bearing aromatic, thien-2-yl or styryl fragments at C-2 position, from easily accessible 5-substituted 3-aminothiophene-2-carboxylates using the Fischer indolization reaction, was developed during this study. Two main steps of this approach are the saponification of the starting 3-aminoesters with sodium hydroxide and next treatment of the crude 3-aminoacids sodium salts with arylhydrazines in glacial acetic acid solution. The latter step includes in situ decarboxylation of the freed 3-aminothiophene-2-caboxylic acids to the 3-aminothiophenes and their acid promoted reaction with arylhydrazines to initially form arylhydrazones of 5-substituted thiophene-3(2H)-ones, which smoothly cause indolization to afford the desired thieno[3,2-b]indoles.     

Palladium-catalyzed arylation of N,N-dialkylhydrazines and the subsequent conversion to anilines

Palladium-catalyzed aminations of different ArBr with N,N-dialkylhydrazines are described. The reaction proceeded in moderate to excellent yield (up to 90%) with good functional groups compatibilities as cyano, ester, ketone and Boc-amine groups are all well tolerated. Several hydrazines were proved to be good coupling partners and this process provided a general method for the isosteric replacement of benzyl amines with arylhydrazines. Moreover, a method for the N-N bond cleavage of arylhydrazines was discovered, and this two-step sequence could be employed as an alternative synthesis of aniline derivatives.     

A microwave-assisted, propylphosphonic anhydride (T3P®) mediated one-pot Fischer indole synthesis

A rapid, mild, and high yielding protocol for the Fischer indolization of arylhydrazines with T3P® under microwave irradiation is described. Significant features of this method include short reaction times and preparative ease.