A correlation method in library search

The identification of unknown pure compounds or mixtures by means of mass spectral library search can be improved by partly resolving the spectra of the individual components within the spectrum of the measured unknown. This is accomplished by investigating sequential spectra in series of spectra; masses with highly correlating sequential intensities are clustered into individual groups. On the assumption that correlated masses belong to the same component spectrum, a filtering algorithm is developed to exclude spectra of non-identical compounds. The basic ideas, methods, examples and experiences gained with applications are reported.     

Towards oligosaccharide library synthesis by fluorous mixture method

The synthesis of an oligosaccharide library by a fluorous tag method is reported here. Several acceptors and donors were mixed and glycosylated. The reaction mixture was purified by chromatography over fluorous HPLC to provide disaccharides in order of increasing fluorine content of the tag. This method could be applied to oligosaccharide libraries consisting of two sets of structural isomers.     

New benzimidazole synthesis

Thermal or acid catalyzed cyclization of several N-(N-arylbenzimidoyl)-1,4-benzoquinoneimines 2 affords 1-aryl-6-hydroxy-2-phenylbenzimidazoles 3 in fairly good yields. Structural proofs and kinetic support for the reaction mechanism are given.     

Microwave assisted straightforward synthetic method for benzimidazole linked quinoxalinones on soluble polymer support

The simple and efficient method was developed for the synthesis of benzimidazole linked quinoxalinones on soluble polymer support using microwave conditions. The acid catalyzed condensation of 4-fluoro-3-nitrobenzoic acid with polymer immobilized o-phenylenediamine, ipso-fluoro nucleophilic substitution with various primary amines and cyclization with acetyl chloride are the key steps involved in implemented linear synthesis. In key cyclization step, the regioselective N-acylation at secondary amine with chloroacetyl chloride followed by spontaneous intramolecular ring closure through ortho-amine functionality generate the quinoxaline skeleton under microwave irradiation. The removal of polymer support and exposure of quinoxalines for auto-oxidation finally produce the benzimidazole linked quinoxalinone derivatives with high purity and yields.     

Investigations of benzimidazole derivatives

3-(1-Methyl-2-benzimidazolyl)acrylic acid was obtained by the reaction of 1,2-dimethylbenzimidazole with chloral and subsequent hydrolysis of the condensation product. The hydrochloride of the chloride of this acid and its esters and amides were synthesized. The methyl and ethyl esters of the acid were synthesized by the Wittig reaction. The IR and UV spectra of the compounds obtained are presented.See [9] for Communication XXIV.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1566–1568, November, 1970.     

Synthesis of benzimidazole derivatives

Phenylhalides of 1-phenyl-2-methylbenzimidazole were synthesized and converted to a new type of imidacyanin dye with phenyl groups on both nitrogen atoms of the benzimidazole residue. The heretofore unknown imidadicarbocyanins were obtained from quaternary salts of 1-phenyl-2-methylbenzimidazole (or its derivatives) which contain electronegative substituents in the 5 position.See [1] for Communication II.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1559–1561, November, 1970.     

Investigation of benzimidazole derivatives

The hydrochlorides of the corresponding 2-benzimidazolylmethylhydroxamoyl chlorides were synthesized by the chlorination of 1-methyl-2-formylbenzimidazole oxime and its 5-methyl and 5-nitro derivatives, and 2-benzimidazolylmethylnitrolic acids were obtained by nitration of the oximes. The products of these transformations react with acetylacetone and benzoylacetone in the presence of bases to give 1,5-substituted 3-[2-benzimidazolyl]-4-acyl-5-methylisoxazoles.See [1] for communication XXVII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 812–815, June, 1972.     

Studies of benzimidazole derivatives

It was found that the formation of 2,5- and 2, 6-azobenzimidazoles, formed during the action of nitrosyl sulfuric acid on 2-amino-2-alkyl (phenyl, benzyl) benzimidazoles, occurs by azo combination of the extremely active salt of benzimidazole-2-diazonium obtained at first with the original amine. The azo compound is formed from 2-aminobenzimidazole substituted in position 5 and 6 only in the presence of 2-dimethylamino-1-methylbenzimidazole or other azo constituents. In the presence of substitutes, which hinder azo combination, 2,2-diazoaminobenzimidazoles stable also in strongly acid medium may constitute the product of the reaction.For part XIX, see [1].     

Synthesis of benzimidazole derivatives

In an aqueous medium, the reaction of N-sodio-2-methylbenzimidazole with monohalogen-substituted nitrogenous aromatic heterocycles containing the halogen in the position to the nitrogen atom may be considered as amethod for obtaining N-betaryl-2-methylbenzimidazoles. 1-(Benzoxazol-2-yl)- and 1-(benzothiazol-2-yl)-2-methylbenzimidazoles have been synthesized; imidacyanine dyes have been obtained with benzothiazol-2-yl groups on the nitrogen atoms of the benzimidazole nuclei from the methiodide of the latter.For Communication V, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1542–1544, November, 1973.     

Research on benzimidazole derivatives

Several transformations of 1-alkyl-3-(2-propynyl)-2-iminobenzimidazolines involving the imino group and the triple bond were studied. It is shown that they are readily isomerized in the presence of bases to alienes, which are then converted to 2-methylimidazo[1,2-a]benzimidazole derivatives by intramolecular cyclization. 1-Alkyl-3-(-bromoallyl)-2-iminobenzimidazolines can be used for the synthesis of the latter.See [1] for communication XXXIV.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 396–400, March, 1975.     

Synthesis of benzimidazole derivatives

A general method for the synthesis of symmetrical imidatricarbocyanines is proposed. A number of dyes of this group were synthesized, and the positions of their light absorption maxima in alcohol solution were determined.See [1] for communication VIII.Translated from Khimiya Geterotsilicheskikh Soedinenii, No. 11, pp. 1562–1563, November, 1976.     

Investigation of benzimidazole derivatives

A number of bis(1-benzimidazolyl)alkanes (I) were synthesized, and their behavior toward sodium amide and potassium hydroxide was studied. While compounds with n=3-5 (Ic-Ie) are aminated by NaNH₂ and hydroxylated by KOH to give diamines (II) and bisbenzimidazolones (III), Ia,b with n=1, 2 decomposed under the influence of these reagents. Considerations regarding the possible reasons for this phenomenon are stated.See [1] for communication XXVIII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1418–1421, October, 1972.     

Research on benzimidazole derivatives

Mercapto derivatives of benzimidazole and imidazole undergo condensation with 2,3-dichloro-1,4-naphthoquinone to give 1,4-naphthoquinonyl derivatives, which can be cyclized to cdioxo derivatives of condensed azole systems.See [2] for communication XXXIX.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 783–785, June, 1976.     

Research on benzimidazole derivatives

The acylation of 2-amino derivatives of benzimidazole and pyridine with-aryl-, -unsaturated carboxylic acid chlorides gave the corresponding amides, which were converted to 2-oxo derivatives of pyrimido [1,2-a]benzimidazole and pyridine by the action of bases.See [1] for communication XLI.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 90–93, January, 1978.     

Research on benzimidazole derivatives

The corresponding 2-hydroxy- and 2-aminobenzimidazoles are formed when 1-methyl-2-phenyl-and 2-alkylbenzimidazoles are fused with potassium hydroxide or sodium amide. N-Dealkylation, dimerization of the benzimidazole derivatives, and cleavage of the heterocyclic ring accompany the principal trends of these transformations.See [1] for communication XXXVIII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 521–524, April, 1976.     

Synthesis of benzimidazole derivatives

New bases and quaternary salts — 2-methylbenzimidazole derivatives — containing 2-pyridyl residues as a substituent in various positions of the benzimidazole ring were synthesized. Benzimidazolium salts of a new type with hetaryl groups attached to both nitrogen atoms were obtained. Imidacyanines were synthesized from the quaternary salts of pyridyl-substituted 2-methylbenzimidazoles, and the chief light-absorption maxima of these dyes were determined.See [1] for communication IVTranslated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 687–690, May, 1972.