Oxidation of vinyl derivatives of benzimidazole-2-thione

N-Vinylbenzimidazole-2-sulfonic acid, 2-benzimidazolyl vinyl sulfoxide, and 2-benzimidazolyl vinyl sulfone were obtained in high yields by the action of concentrated hydrogen peroxide and acetyl hydroperoxide on N- and S-monovinyl derivatives of benzimidazole-2-thione. N-Vinyl-2-benzimidazolone and a complex mixture of polymeric products are formed in the oxidation of N,S-divinyl-2-mercaptobenzimidazole. It is shown that the reactivity of the sulfur atom depends on the number of vinyl groups and their orientation with respect to the heteroatoms.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1670–1673, December, 1975.     

Bromination of vinyl derivatives of benzimidazole-2-thione

The reaction of vinyl derivatives of benzimidazole-2-thione with bromine was investigated. It is shown that the principal reaction is the addition of the halogen to the double bond of the vinyl group. Depending on the structure of the starting vinyl derivative, elimination of hydrogen bromide or halogenation at the heteroring nitrogen atom, which leads to the formation of hydrohalides, is subsequently possible.Translated, from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1092–1094, August, 1982.     

A facile and efficient synthesis of bisazine derivatives

1,4‐Phenylenediamine was condensed with acetylacetone to give 4,4′‐[1,4‐phenylenedi‐(nitrilo)]‐dipenten‐2‐ol 1 . Compound 1 reacted with different organic reagent to give bisazine derivatives. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:293–299, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20017     

Synthesis and NMR spectroscopic assignment of chlorinated benzimidazole-2-thione derivatives

The benzimidazole-2-thione scaffold is present in many drugs encompassing various therapeutic areas. Due to the broad spectrum of bioactivities it also represents an important starting point in drug discovery campaigns, especially those based on fragment-based design. Despite simple structures the tautomerism and regioisomerism of substituted benzimidazole-2-thiones makes unambiguous structural analysis difficult. Tautomeric duplicates are present in commercial libraries resulting in two tautomers being sold as different products. To showcase an example of appropriate structural determination, we synthesized and characterized a set of benzimidazole-2-thiones with different positions of a chlorine atom on the ring. Using NOESY and ¹³C NMR spectroscopy, we determined that the thione tautomer predominates in the thione-thiol equilibrium. Furthermore, NOESY and HMBC experiments confirmed the position of the substituents on the benzimidazole-2-thione ring.     

A new and efficient one-pot procedure for the synthesis of 2-styrylquinolines

A one-pot combination of a modified Friedländer annulation and a Knoevenagel condensation provides 2-styrylquinolines in good to excellent yields. A variety of substrates are reacted in one-pot in the presence of 1-methylimidazolium trifluoroacetate ([Hmim]TFA).     

Kinetics of the acidic hydrolysis of vinyl derivatives of benzimidazole-2-thione and benzoxazol-2-one and -2-thione

The kinetics of the acidic hydrolysis of seven vinyl derivatives of benzimidazole-2-thione and benzoxazol-2-one and -2-thione were studied by means of polarography. The rate constants and energies of activation of the reaction were determined. The hydrolytic stabilities of the compounds depend on the nature of the heteroring and the site to which the vinyl group is attached.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1532–1535, November, 1982.     

An efficient and facile procedure for synthesis of octyl polyglucoside

Nonionic surfactant alkyl polyglucoside (APG) was prepared by direct glycosidation of alkyl alcohol with glucose in the presence of sulfate acid-silica gel (H_2SO_4/SiO_2) as solid acidic catalyst.The quantity of catalyst was only of 1 wt%,based on the glucose,and the conversion of glucose was close to 100% at 110℃in 1.5h.The product was characterized by FT-IR,mass and ~1H NMR spectra.The degree of polymerization (DP) of the glucose in the product was 1.37,and critical micelle concentration (CMC) of product was only 0.0104 wt%.     

Reaction of benzimidazole-2-thione with 1,2-dibromoethane. Coronand synthesis

Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, p. 136, January, 1990.     

A facile electrochemical method for synthesis of new benzofuran derivatives

Electrooxidation of 3-substituted catechols has been studied in the presence of dimedone in aqueous solution, using cyclic voltammetry and controlled-potential coulometry. The results indicate that the quinones derived from catechols participate in Michael addition reactions with dimedone to form the corresponding benzofuran derivatives (6a-c). We propose a mechanism for the electrode process. The efficient electrochemical synthesis of 6a-c has been performed at carbon rod electrodes in an undivided cell using a constant current.     

A simple and efficient procedure for the synthesis of optically active s-triazolothiadiazole derivatives

A series of novel s-triazolothiadiazoles 3a-h were prepared by condensation reaction of substituted amino triazoles la-b with N-phethaloyl-L-amino acids 2a-d in the presence of the phosphoroxy chloride（POCl₃） as an anhydrous reagent.The structure of all synthesized compounds was confirmed by IR,¹H NMR,and ¹³C NMR spectroscopy.     

Acylation of purine-8-thione and benzimidazole-2-thione: A reinvestigation of the site of acylation

Purine-8-thione ( 1 ) is acylated on nitrogen, not on sulfur as was previously reported. Thus, the reactions of 1 with ethyl chloroformate and with acetic anhydride yield, respectively, ethyl purine-8-thione-9( 7 )-carboxylate ( 3 ) and 9 ( 7 )acetylpurine-8-thione ( 7 ) as shown by independent synthesis and spectra. In like manner, benzimidazole-2-thione ( 10 ) reacts with acetic anhydride, ethyl chloroformate, benzoyl chloride, and cyclohexyl isocyanate to yield the corresponding N-acylated derivatives. In addition, 10 yields 1,3-dibenzoylbenzimidazole-2-thione on treatment with 2 equivalents of benzoyl chloride.     

A new and efficient N-alkylation procedure for semicarbazides/semicarbazones derivatives

An easy to perform and regioselective synthesis of N-alkyl hydrazones/hydrazides is described, which uses an aprotic medium with kinetic control. This procedure produced the desired monoalkylated or dialkylated amines with excellent yields and selectivities.     

Reaction of benzimidazole-2-thione with cyanoacetylene alcohols

Conclusions 2-Iminobenzimidazo-1,3-thiazines containing a hydroxyl group were obtained by the reaction of benzimid-azole-2-thione with tertiary cyanoacetylene alcohols. It was observed that they have enhanced stability toward alkalis.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1903–1904, August, 1984.     

A facile and efficient synthesis of new fluoroalkylsulfonates and the corresponding tetrabutylammonium salts

A useful synthetic methodology towards new fluoroalkylsulfonates was developed. Grignard addition to an inexpensive and commercially available fluorine-containing ester, methyl 2,2-difluoro-2-(fluorosulfonyl)acetate (1) gave the mono-adduct (2) as the only product in high yield. The scope and limitation of this method were thoroughly investigated and it was found that it works for most Grignard reagents except electron-poor ones. Interestingly, the resulting fluoroalkylsulfonates exhibit substituent-dependent hydration behavior due to the presence of carbonyl group in these compounds. Converting the fluoroalkylsulfonate to the acid form and then neutralizing it with tetra-n-butylammonium hydroxide gave the corresponding tetra-n-butylammonium salts, which shows good solubility in common organic solvents, some of which might be suitable for copolymerization with other hydrophobic monomers.     

A facile and efficient stereoselective synthesis of highly functionalised trisubstituted alkene derivatives of ferrocenealdehyde

The reaction of the Baylis–Hillman adduct 2 of ferrocenealdehyde with various oxygen and carbon nucleophiles in the presence of montmorillonite K10 clay catalyst furnished highly functionalised trisubstituted alkene derivatives of ferrocenealdehyde in excellent yield. Synthetic use of one of products 7 has been demonstrated with the synthesis of a 1,3-diyne ether derivative of ferrocene 16 via an Eglinton coupling reaction.     

A highly facile and efficient one-step synthesis of N6-adenosine and N6-2'-deoxyadenosine derivatives

[reaction: see text] A highly facile and efficient one-step synthesis of N6-adenosine and N6-2'-deoxyadenosine derivatives has been developed. Treatment of inosine or 2'-deoxyinosine, without protection of sugar hydroxyl groups, with alkyl or arylamines, in the presence of BOP and DIPEA in DMF, led to the formation of N6-adenosine and N6-2'-deoxyadenosine derivatives in good to excellent yields. Carcinogenic polyaromatic hydrocarbon (PAH) N6-2'-deoxyadenosine adduct 10 and a rare DNA constituent 11 were thus synthesized directly from 2'-deoxyinosine both in 98% yield.     

A facile aminocyclization for the synthesis of pyrrolidine and piperidine derivatives

Bromination of an isolated double bond followed by aminocyclization furnishes a highly stereoselective protocol for the intramolecular formation of pyrrolidine and piperidine ring containing subunits that are presented in numerous biologically active natural products.