Synthesis and catalytic activity of novel xylyl‐linked benzimidazolium salts

The reaction of 1‐alkylbenzimidazole derivatives with o‐/p‐di(chloromethyl)benzene results in the formation of the new o‐/p‐xylyl‐linked bis(benzimidazolium) salts, 1 and 2, respectively. The salts were characterized by NMR spectroscopy and elemental analysis. The in situ prepared complexes derived from Pd(OAc)₂–1 and 2 exhibit catalytic activity (61–98%), to give the Heck coupling products of aryl bromides and styrene. Copyright © 2009 John Wiley & Sons, Ltd.     

Synthesis of 4,4-diphenyl-7-oxodibenzodihydro-1,4-diazepinium salts

Conclusions The salt of a new completely aromatic ammonium cation, namely 4, 4-diphenyl-7-oxodibenzo-1, 4-dihydrodiazepinium iodide, was obtained, the structure of which was confirmed by qualitative tests with silver hydroxide, aqueous NaOH solution, and nitrosylsulfuric acid.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1096–1101, May, 1973.     

Synthesis of well-defined telechelic trans-1,4-polyisoprene by oxidative cleavage

Synthesis of telechelic trans-1,4-polyisoprenes(TPI: trans-structure 95%) was evaluated based on two different methods of oxidative cleavage(indirect cleavage: first epoxidation of TPI, then the selective cleavage of epoxidized units in epoxidized trans-1,4-polyisoprene(ETPI) and direct cleavage of isoprene units in TPI). The influence of solvents and the ratio of oxidative agents was investigated by 1H-NMR and 13C-NMR. A series of well-defined telechelic TPI with double terminated functional groups and less side reaction(molecular weight distribution range: 1.96?2.26) were synthesized by indirect cleavage in chloroform. Telechelic TPI showed similar crystallization behavior with TPI and interesting cold crystallization behavior characterized by DSC.     

Novel synthetic method for ketones from substituted benzimidazolium salts and Grignard reagents

A new synthetic method of ketones from substituted benzimidazolium salts and Grignard reagents is reported. The influences of the various Grignard reagents on the yield of ketones and the mechanism are discussed.     

2-Methylpyridinium salts as 1,4-dinucleophiles. Quinolizinium salts from the westphal condensation

Condensation of 2-methylpyridinium salts with 1,2-dicarbonyls in the presence of base, yielded 2,3-disubstituted quinolizinium compounds. Results obtained with different pyridinium substrates are discussed.     

Effect of substituents on the properties of 2-(o-hydroxystyryl) benzimidazolium salts

The results of a calculation of the benzimidazolium cation and its 5(6)-substituted derivatives by the Hückel MO method show that the ±I effects of substituents have a considerably lesser influence on the magnitude of the charge on the C₍₂₎ atom than ±M effects. Replacement of C₍₅₎ by a positively charged nitrogen atom (imidazo[4,5-c]pyridinium dication) increases the charge on C₍₂₎ to the same extent as the introduction of a substituent with a vacant p_Z orbital into the 5 position. In accordance with this, the methyl group in the 2 position of the 1,2,3,5-tetramethylimidazolio[4,5-c]pyridinium ion condenses with salicylaldehyde, but the merocyanine cannot be isolated from the 1,3,5-trimethyl-2-(o-hydroxystyryl) imidazolio[4,5-c]pyridinium diperchlorate because of the irreversible degradation of the latter.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 683–686, May, 1972.     

N-Heterocyclic carbenes: VI. Abietane-based chiral benzimidazolium salts as N-heterocyclic carbene ligands in the heck reaction

New chiral benzimidazolium salts were synthesized on the basis of abietane and were used as N-heterocyclic carbene ligands in the Heck reaction.     

Synthesis of new benzimidazolium salts with tunable emission intensities and their application as fluorescent probes for Fe in pure aqueous media

A series of novel, water-soluble benzimidazolium salts with common ‘fluorophore–spacer–receptor’ PET design has been synthesized. Despite the common PET scaffold these benzimidazolium salts displayed diverse emission intensities in pure aqueous solutions. The observed emission intensities were found to be influenced by the functionalized alkyl side arms present on the benzimidazolium ring. These benzimidazolium salts were also found to act as selective sensors for Fe³⁺ ions over other metal ions like Na⁺, K⁺, Ca²⁺, Mg²⁺, Ba²⁺, Al³⁺, Cr³⁺, Co²⁺, Ni²⁺, Mn²⁺, Zn²⁺, Pb²⁺, Ag⁺, Cu²⁺ and Hg²⁺ in pure aqueous media.     

A versatile synthesis of substituted benzimidazolium salts by an amination/ring closure sequence

[reaction: see text]. A new method to produce benzimidazolium salts based on a successive Buchwald-Hartwig amination and ring closure is reported. A variety of different benzimidazolium salts can be prepared using this procedure. Amines that bear an alpha-chiral group undergo the reaction to furnish chiral benzimidazolium salts. The salts that lack a C2 substituent on the heterocycle are readily deprotonated to give nucleophilic carbenes.     

Synthesis of photoactive 1-methyl-1-R-4-(1,4-dioxo-1,4-dihydronaphthalen-2-yl)piperazinium salts

Photoactive 4-(1,4-dioxo-1,4-dihydronaphthalen-2-yl)piperazinium salts were synthesized by alkylation of 3-chloro-2-(piperazin-1-yl)- and 2-arylamino-3-(4-methylpiperazin-1-yl)-1,4-naphthoquinones. Light sensitivities of materials obtained by adsorption of the synthesized piperazinium salts from solution onto oxidized aluminum support were estimated.     

Synthesis and spectral characterization of new benzimidazolium compounds containing sulfur

Abstract

N-heterocyclic carbene (compound b) was synthesized from reaction of 1-(3-phenylpropyl)-3-methylbenzimidazolium iodide (a) and a strong base in an argon atmosphere. Then, 1-(3-phenylpropyl)-3-methylbenzimidazolium-2-carbodithioate (c) was prepared with carbene and CS₂. Finally, a group of alkyl 1-(3-phenylpropyl)-3-methylbenzimidazolium-2-carbodithioate halides was synthesized with alkyl halides and compound c, occurring products 1-6. Structural characterization of compounds was performed ¹H, and ¹³C NMR, IR, and MS spectroscopy and elemental analysis.     

Reaction of 1,4-benzoquinones with PH-phosphonium salts

A novel approach has been proposed to the synthesis of phosphonium salts containing a 1,4-dihydroxybenzo fragment via reaction of 2-methyl-1,4-benzoquinone or 2-isopropyl-5-methyl-1,4-benzoquinone with PH-phosphonium salts generated in situ from triphenylphosphine and trifluoromethanesulfonic or trifluoroacetic acid. The structure of the synthesized phosphonium salts was determined by NMR spectroscopy and X-ray analysis.     

Synthesis of indoles from pyridinium salts.

The reaction of 1,2,5,6-tetramethyl-3-nitropyridinium perchlorate with acetone and piperidine on a solid carrier has given the novel, relatively stable 3-nitropyridine anhydro-base, 1,2,5-trimethyl-3-nitro-6-methylene-1,6-dihydropyridine, which bears alkyl groups only. This anhydro-base has been shown not to be an intermediate in the synthesis of indoles from 3-nitropyridinium salts.See [1] for Communication 7.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1214–1216, September, 1990.