New aromatic systems having a fused thiazolium ring

The method developed for the synthesis of thiazolo[3,2-a]pyridinium salts has been extended to the first synthesis of simple thiazolo[3,2-a]pyrimidinium, thiazolo[3,2-a]-pyrazinium and thiazolo[2, 3-b]benzo[d]thiazolium salts. No method could be found for the cyclization of 4′-bromo-2-(2-benzoxazolylthio)acetophenone to the thiazolo[2,3-b]-benzoxazolium system.     

Polymers by the reaction of bis(pyrylium salts) with diamines: A novel approach to ionene polymers

The following reactions of pyrylium salts with amines are described: (1)bis(pyrylium salts) with amines; (2) diamines with pyrylium salts; and (3) bis(pyrylium salts) with diamines. Both (1) and (2) give bis(pyridinium salts) in high yields, and (3) gives the corresponding polymers which are isolated and characterized. This procedure was applied to cationic bis(pyrylium salts) to give cationic dimers and polymers, and further to zwitterionic bis(pyrylium salts) to yield the corresponding zwitterionic dimers and polymers.     

Synthesis and Structure of 1-tert-Butyl-3-R-tetrazolium Salts

An effective method was developed for the synthesis of 1,3-disubstituted tetrazolium salts by the quaternization of 2-monosubstituted tetrazoles, including functionally substituted compounds, with tert-butanol in 72% perchloric acid. An X-ray diffraction investigation of examples of this series of salts - 1-tert-butyl-3-(1-methylvinyl)- and 1,3-di-tert-butyltetrazolium perchlorates - was carried out.     

A DFT Study of the Structure and Relative Stability of 1,3-Thiasilacycloalkanes and Their S-Functional Derivatives

A series of 1,3-thiasilacycloalkanes and their S-oxides, S,S-dioxides, and sulfonium salts were studied by the DFT (B3LYP/6-31G*) method. In six-membered sulfoxides, the oxygen atom preferentially occupies the axial position, whereas in the corresponding sulfonium salts the S-alkyl group occupies the equatorial position. The calculation results explain the lower hydrolytic stability of the five-membered rings compared to the six-membered analogs and the lower stability of sulfoxides compared to sulfones.     

Electrophilic heterocyclization of 4,5-disubstituted 3-allylthio-4<Emphasis Type="Italic">H</Emphasis>-1,2,4-triazoles by the action of halogens

A study was carried out on the regioselectivity of the electrophilic heterocyclization of 4,5-disubstituted 3-allylthio-4H-1,2,4-triazoles by the action of bromine and iodine. Factors affecting the halogenation regioselectivity, namely, the nature of the electrophilic reagent and the presence of lithium perchlorate, were studied. A method was developed to obtain 5,6-dihydro-3H-[1,3]thiazolo[3,2-b]triazolium salts. The structure of these salts was confirmed by spectral methods and chemical transformations.     

Investigation of the Effect of Various Substituents on the Density of Tetrazolium Nitrate Salts as Green Energetic Materials

The substitution effect of various functional groups such as –NO₂, –CN, –N₃, –NF₂, and –NH₂ on the density of tetrazolium nitrate salts is investigated through multiple linear regression method. The methodology of this work introduces a new model, which related density of tetrazolium nitrate salts to the number of fluorine and nitrogen atoms, the presence of NF₂ groups, NO₂ groups, as well as CH₃ groups in the structural formula. The new reliable correlation shows that the NF₂ and NO₂ group can cause increasing the density of tetrazolium nitrate salts, especially NO₂, whereas the CH₃ group can decrease their density. The new proposed relationship has good reliability and predictability, so it can be used to design new rich nitrogen compounds based on tetrazolium nitrate salts as green energetic materials. These results are also tested for N,N′‐azo‐1,2,4‐triazolium nitrate salts, which is caused to derive another correlation. This correlation shows that the presence of NF₂ functional groups increases the density of N,N′‐azo‐1,2,4‐triazolium nitrate salts as well as the value of n_O/n_C.     

The effect of short alkane bridges in stability of bisbenzimidazole-2-ylidene silver(I) complexes: synthesis,crystal structure and antibacterial activity

Three bisbenzimidazolium salts, 3,3-(alkane-1,n-diyl)bisbenzylbenzimidazolium dibromide/dihexafluorophosphate (1a/b–3a/b) (where alkane?=?ethane, propane or butane and n?=?2, 3, or 4), were synthesized. The bromide salts were subsequently used as precursors to prepare their respective Ag(I)-NHC complexes via in situ deprotonation method. The successful formation of all bisbenzimidazolium salts and complexes were proved by elemental analysis, ¹H-NMR, ¹³C-NMR and FT-IR analyses. From single-crystal X-ray diffraction analyses, 4 has been established as a binuclear complex with the molecule arranged as in trans-conformation. Salts 1b–3b and Ag(I)-NHC complexes 4–6 were then screened for their antibacterial potential against E. coli (ATCC 25922) and S. aureus (ATCC 12600). All the bisbenzimidazolium salts do not show any activity against both bacteria while 4 exhibits the highest activity against both bacteria in all methods followed by 5 and 6.     

First Synthesis of Thiophene Thioglycosides

A new method for the preparation of a new class of thiophene thioglycosides via one-pot reaction of the sodium thiophenethiolate salts with 2,3,4,6-tetra-O-acetyl-α-D-gluco- and galacto-pyranosyl bromides has been studied. The sodium thiophenethiolate salts are prepared using cyano-di-thioic analogs and their corresponding mono- and dithiolate salts.     

Keto-stabilized Arsenic Ylides and their Coordination to Gold(I)

Three different arsonium salts were prepared by a solvent-free method from Ph₃As and the respective 2-bromoacetophenones. These salts were deprotonated by NaOH to form keto-stabilized arsenic ylides. The ylids react with [AuCl(tht)] affording gold(I) complexes containing the C-bound ylide. The compounds were characterized by NMR spectroscopy, IR spectroscopy, and X-ray diffraction.     

Design and Synthesis of the First Thiophene Thioglycosides

A novel reported method for preparation of the first thiophene thioglycosides via a one-pot reaction of sodium thiophenethiolate salts with 2,3,4,6-tetra-O-acetyl-α-D-gluco- and galactopyranosyl bromides has been studied. The sodium thiophenethiolate salts were prepared using sodium cyanoethylene thiolate salts.     

Intramolecular photocyclization of N-[(2-haloaryl)methyl]pyridinium and n-(arylmethyl)-2-halopyridinium salts

Various N-[(2-haloaryl)methyl]pyridinium, N-(arylmethyl)-2-halopyridinium and N-(2-halobenzyl)iso-quinolinium salts have been synthesized and their intramolecular photocyclization reactions studied. Upon irradiation the aqueous solution of N-[(2-haloaryl)methyl]pyridinium, and N-arylmethyl-2-halopyridinium salts 1, 2 were cyclized to give isoindolium salts. In contrast to the pyridinium salts 1, 2 , the aqueous solution of N-(2-halobenzyl)isoquinolinium salts 3 appear not to undergo photocyclization. N-Benzyl-2-chloropyridinium salts 1c is more reactive than N-(2-chlorobenzyl)pyridinium salt 1a in the photocyclization. N-(2-Chlorobenzyl)-2-chloropyridinium salt 1d is three times more reactive than 1c . A mechanism of π-complex formation of the halogen moiety of the pyridinium ring with the phenyl ring is suggested for the reactive pyridinium salt. The triplet energy of the isoquinolinium salts 3 is tool low to photocyclize.     

A versatile synthesis of benzothieno-annelated 1,2-dihydropyridine and 1,2,3,4-tetrahydropyridine derivatives: the effect of the structure of benzothieno-annelated pyridinium salts on their reduction by sodium borohydride

Abstract  

Benzothieno[2,3-c]pyridinium and benzothieno[2,3-c]quinolinium salts were synthesized either by quaternization of benzothieno[2,3-c]pyridines, or recyclization of benzothieno[2,3-c]pyrylium salts with primary amines. One-pot synthesis of benzothieno[3,2-g]indolizinium salts from 1-(3-chloropropyl)-benzothieno[2,3-c]pyrylium included consequent recyclization of the pyrylium core by ammonia into a pyridine intermediate and its further intramolecular quaternization reaction. Depending on the structure of benzothieno-annelated pyridinium salts, their reaction with sodium borohydride in methanol results in reduction of the pyridine core into tetrahydropyridine or dihydropyridine derivatives. Whereas reduction of benzothieno[2,3-c]pyridinium and benzothieno[3,2-g]indolizinium salts readily yields benzothieno-annelated tetrahydropyridines as a complex mixture of stereoisomers, reduction of benzothieno[2,3-c]quinolinium salts results in dihydropyridine derivatives. The structure of the latter, in particular, was confirmed by single-crystal X-ray diffraction analysis.     

The synthesis and hydrolysis of N-benzyl-S-methylisothiazolidinium salts

A series of N-benzyl-S-methylisothiazolidinium salts were obtained by iodinic oxidation of the corresponding N-benzyl-3-methylthiopropylamines at neutral pH followed by their isolation as the chloride salts. The parent N-benzyl-3-methylthiopropylamines were prepared by reacting substituted benzaldehydes with 3-methylthiopropylamine and sodium cyanoborohydride. Acid hydrolysis of the isothiazolidinium salts resulted in their quantitative conversion to the corresponding N-benzyl-3-methylsulfenylpropylamines. Although methylsulfenylpropylamine formation also predominated in alkaline solution, a significant fraction was converted to the parent benzaldehyde and presumably, 3-methylthiopropylamine. The latter conversion is believed to involve opening of the isothiazolidine ring via an elimination reaction followed by hydrolysis of the resulting Schiff's base.     

Reactions of 1-alkylbenzimidazolium 3-imines with acetylenic compounds and benzaldehyde

1-Alkyl-3-aminobenzimidazolium salts react with dimethyl acetylenedicarboxylate or dibenzoylacelylene in the presence of base to produce unusual 1:1 adducts, 1-(2′-alkylaminophenyl)-pyrazole derivatives. Treatment of the 3-amino salts with benzaldehyde in the presence of alkali gives benzaldehyde 2-(N,N-acylalkylamino)phenylhydrazones. The same hydrazones are obtained by alkaline treatment of 1 -alkyl-3-benzaliminobenzimidazolium salts, which are prepared from the 3-amino salts and benzaldehyde.     

Arylthiosulfonium salts as transfer agents of the S-aryl group to double bonds

Conclusions A general method was developed for the preparation of arylthiosulfonium salts which are active transfer agents for the S-aryl group in reactions with alkenes, leading to the formation of-arylthioalkylsulfonium or S-arylepisulfonium salts.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 378–386, February, 1982.The authors express their gratitude to V. A. Chertkov for taking the low-temperature PMR spectra.     

The Synthesis of (3,5-DI-tert-butyl-4-hydroxyphenyl)methyl-(3-pyridylalkyl)-ethers via 1-(3,5-Di-tert-butyl-4-hydroxyphenyl)methyl Pyridinium Salts.

The rearrangement of 1-(3,5-di-tert-butyl-4-hydroxyphenyl)methyl pyridinium salts under basic conditions is described. A method for the synthesis of (3,5-di-tert-butyl-4-hydroxyphenyl)methyl-(3-pyridylalkyl)-ethers is elaborated.     

Impact of Substituents Attached to N-Heterocyclic Carbenes on the Catalytic Activity of Copper Complexes in the Reduction of Carbonyl Compounds with Triethoxysilane

By using functionalized imidazolium salts such as 1‐allyl‐3‐alkylimidazolium or 1‐alkyl‐3‐vinylimidazolium salts as carbene ligand precursors, the reduction of aryl ketones with triethoxysilane may be catalyzed by copper salt/imidazolium salt/KO^tBu systems. The functional substituents attached to the N‐heterocyclic carbene (NHC) serve to enhance the catalytic activity. Different copper salts also have an effect on the catalytic activity, with copper(II) acetate monohydrate being superior to copper(I) chloride.     

Preparation and Structures of 2‐Substituted 5‐Benzyl‐3‐methylimidazolidin‐4‐one‐Derived Iminium Salts,Reactive Intermediates in Organocatalytic Transformations Involving α,β‐Unsaturated Aldehydes

Preparations of the title compounds, 5 – 7 (Scheme 1 and Table 1), of their ammonium salts, 9 – 11 (Scheme 2 and Table 2), and of the corresponding cinnamaldehyde‐derived iminium salts 12 – 14 (Scheme 3 and Table 3) are reported. The X‐ray crystal structures of 15 cinnamyliminium PF₆ salts have been determined (Table 4). Selected ¹H‐NMR data (Table 5) of the ammonium and iminium salts are discussed, and structures in solution are compared with those in the solid state.     

Thermochemistry of complex salts of transition metal perchlorates with tetrazole ligands

The combined use of combustion and solution calorimetry was proposed as a method for determining the standard enthalpy of formation of the complex salts of transition metals, viz., cobalt(II), nickel(II), and zinc, with the organic ligand (5-aminotetrazol-1-yl)acethydrazide. The enthalpies of solution in water and in a 0.1 M solution of hydrochloric acid were measured for the complex salts and ligand. The enthalpy of combustion of the ligand was determined by the combustion calorimetry method, and its standard enthalpy of formation was calculated. The thermochemical cycle was developed for determining the standard enthalpy of formation of the complex salts. The reliable values of the enthalpies of formation of the salts in the standard states were obtained, and the enthalpies of formation of the earlier unknown complex ions were determined.     

Studies on quinoline derivatives and related compounds. 1. A new synthesis of 1-alkyl-1,4-dihydro-4-oxo-3-quinolinecarboxylic acids

A novel preparative method for 1-alkyl-1,4-dihydro-4-oxo-3-quinolinecarboxylic acids was developed. The key process is the cyclization of N-alkylanilinomethylenemalonales, which was effected successfully in the presence of polyphosphoric acid, polyphosphate ester, boron tri-fluoride or a mixture of acetic anhydride and sulfuric acid. With phosphorus oxychloride, N-alkylanilinomethylenemalonates yielded 1-alkyl-4-chloro-3-carbethoxyquinolinium salts which were hydrolyzed readily to ethyl 1-alkyl-1,4-dihydro-4-oxo-3-quinolineearboxylates or their acids. By means of this novel method several new 1-alkyl-1,4-dihydro-4-oxo-3-quinolineearboxylic acids were prepared.