Synthesis and properties of 5-diazoimidazoles and imidazolyl-5-diazonium salts

Diazotization of 4-R-5-aminoimidazoles (R = CONHAr, CONHAlk, morpholinocarbonyl, or piperidinocarbonyl) with sodium nitrite in aqueous solutions of mineral acids afforded the corresponding 5-diazoimidazoles, whereas the reactions in concentrated tetrafluoroboric acid produced imidazolyl-5-diazonium salts. In the solid phase, diazonium salts are transformed into the corresponding diazo compounds.     

4-Quinolone fused heterocyclic ring systems by intramolecular reactions of 4-quinolone-2-carboxamides

A versatile synthetic route to new 4-quinolone-based polycyclic systems is described. TFA-catalyzed intramolecular reaction of N-unsubstituted quinolone-2-carboxylic acid amides gives structurally diverse compounds, depending on the length of the chain. Acid treatment of β-oxoamides furnishes 3H-pyrazino[1,2-a]quinoline-4,6-diones, due to the nucleophilic attack of N-1 to the carbonyl group, whereas TFA treatment of δ- and ε-oxoamides leads to the formation of tetracyclic compounds by a tandem heteroannulation reaction.     

Some reactions of 4H-pyrylium salts with tributylphosphine and with tertiary amines

The phosphonium salt from tributylphosphine and 2,6-di(4-methoxyphenyl)pyrylium perchlorate (3) reacted with diisopropylethylamine in acetonitrile to give 2,2′,6,6′-tetra(4-methoxyphenyl)-Δ^4.4′-bi-4H-pyran in quantitative yield. The reaction of 3 and other 4H-pyrylium salts with tertiary amines gave 4H-pyrans.     

Heterocyclic diazo compounds. 5. Reaction of benzimidazole-2-diazonium salts with naphthols and their ethers

The principal pathways for the reaction of benzimidazole-2-diazonium ion salts with naphthols and their methyl ethers in a mixture of phosphoric acid annd acetic acid have been elucidated. In concentrated acidic media, in addition to substitution at the 4-position in naphthol and its ether, azo coupling at the 8-positin is also possible. It has been found that a 2-methoxy group in naphtylazobenzimidazole exhibits anomalously high reactivity with respect to hydrolytic cleavage, which explains the observed ease of dealkylation of the azo compound during the course of the azo coupling sequence.For Communication No. 4, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 67–72, January, 1992.     

Diazo compounds of the heterocyclic series. 4. Some peculiarities of the diazo coupling of benzimidazole-2-diazonium salts with phenols and their ethers

The corresponding hydroxy (methoxy)-substituted azobenzimidazoles were obtained by diazo coupling of benzimidazole-2-diazonium salts with phenols and their complete and incomplete ethers in strongly acidic media; in the case of phenol ethers the process is complicated by dealkylation of the methoxy group in the ortho position relative to the azo bridge.See [1] for Communication 3.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 637–642, May, 1990.     

Pyrazole-3(5)-diazonium salts in the synthesis of novel pyrazolo[5,1-c][1,2,4]triazines

Coupling of pyrazole-3(5)-diazonium salts with cyclic 1,3-dicarbonyl (active methylene) compounds followed by cyclocondensation of the resulting hetarylhydrazones gave novel pyrazolo[5,1-c][1,2,4]triazines.     

Some reactions of 5-methyl-11H-isoindolo[2,1-α] benzimidazolium salts

5-Methyl-11H-isoindolo[2,1-α]benzirnidazolium halide (IV), obtained by direct quaternization of the precursor III, underwent facile condensation reactions at its 11-methylene group similar to those of 11H-isoindolo[1,2-b]benzothiazolium cation II. Although the treatment of II with alkali regenerated its precursor I, treatment of IV with alkali caused ring opening to a phthalimidine. Attempted thermal cyclization of 2-(alkylaminophenyl)phthalimidines, e.g., VII, resulted in dealkylation to produce III.     

Synthesis of some 4-chlorobenzopyrylium salts and their reactions

4-Chlorobenzopyrylium and 4-chloroflavylium salts have been synthesized, and some reactions of benzopyrylium cations of this type have been studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 6, No. 8, pp. 1028–1030, August, 1970.     

Transformations of 3-alkyl-4-(methoxyphenyl)-1<Emphasis Type="Italic">H</Emphasis>-pyrazole-5-diazonium salts

The coupling of 3-alkyl-4-(methoxyphenyl)-1H-pyrazole-5-diazonium salts with acetylacetone followed by cyclization of the formed heterylhydrazones resulted in pyrazolo[5,1-c][1,2,4]triazines. The 4-(3,4-dimethoxyphenyl)-3-methyl-1H-pyrazole-5-diazonium salt was not involved into a similar reaction but suffered an intramolecular azo coupling giving pyrazolo[3,4-c]-cinnoline.     

Isoparametric correlations in reactions of 4-R-N-arylpyridinium salts with arylamines

Isoparametric dependencies of the structure of the reagents (including non-catalytic rate constants, substitution constants σ⁰, basicity constants, and charges at the reaction centers) have been obtained for the reactions between 4-R-N-(2,4-dinitrophenyl)pyridinium salts with arylamines. The electron-acceptor 4-R-substituents studied reduced the positive charge on the reaction center (the α-atom) and the nitrogen atom of the N-arylpyridinium cation. L. M. Litvinenko Institute of Physical Organic and Coal Chemistry, National Academy of Sciences of Ukraine, 70 R. Luxembourg ul., Donetsk 340114, Ukraine. Translated from Teoreticheskaya i éksperimental'naya Khimiya, Vol. 35, No. 4, pp. 231–235, July–August, 1999.     

磺化杯芳烃与二苯胺重氮盐的包结物

磺化杯芳烃与二苯胺重氮盐形成摩尔比为1：1的包结物，在磺化杯芳烃存在时，二苯胺重氮盐的吸光强度下降，吸收峰红移，核磁共振氢谱的化学位移向高场移位。杯芳烃的环越大，与重氮盐的结合常数越大。在磺化杯芳烃的存在下，重氮盐的热稳定性提高，同时仍保持较高的光敏性。     

The reactions of 5-aryl-2,3-dimethylisoxazolium salts with aromatic aldehydes

The reactions of the 3-methyl group in 5-aryl-2,3-dimethylisoxazolium tetrafluoroborates with aromatic aldehydes, in the presence of piperidine were studied. Isoxazolium salt reactivity is independent of the phenyl group substituent at C-5 on the isoxazolium salt ring. However, it does depend on the aldehyde structure.     

Inclusion Complexation of Diphenylamine-4-diazonium Chloride and p-Sulfonatocalix[4]arene

Inclusion complexation of p-sulfonatocalix[4]arene (SC4A) and diphenylamine-4-diazonium chloride (DDC) in aqueous solution was investigated in this study. The inclusion of DDC in the cavity of SC4A leads to ¹H NMR chemical shifts of DDC moving towards higher magnetic field. The complexation of SC4A also results in a bathochromic shift and a decrease in optic intensity of the absorption spectrum of DDC. In the presence of SC4A, the thermal stability of DDC in aqueous solution increases significantly while its photosensitivity still remains high.     

二苯胺重氮盐与十二烷基硫酸钠在水溶液中的相互作用

报道了二苯胺-4-重氮盐(DDS)与十二烷基硫酸钠(SDS)在水溶液中的相互作用.实验结果表明,体系粘度随SDS/DDS物质的量比(ξ)的变化而急增急降.当ξ=0～0.9时,二者形成沉淀,体系的粘度基本不变;当ξ=1.9～2.3时,沉淀溶解并伴随着体系粘度急增,最高粘度达初始值的2520倍;之后,随ξ的增大,体系粘度迅速下降至初始值.对DDS-SDS聚集体的微观结构与体系粘度的关系进行了初步讨论.同时发现体系粘度是光敏性的,紫外光照可使其迅速下降.     

Synthesis of 4(5H)-oxazolonium salts

Chemistry of Heterocyclic Compounds -