Spektrophotometrische Bestimmung von Dehydrokondensationsprodukten der Pyrazine und Chinoxaline

Zusammenfassung Die Absorptionsspektren folgender Verbindungen: Chinoxalin, 2,2-Dichinoxalyl, 2-Methylchinoxalin, 3,3-Dimethyl-2,2-dichinoxalyl, Pyrazin, 2,2-Dipyrazyl, 2-Methylpyrazin und 5,5-Dimethyl-2,2dipyrazyl wurden in Methanol im Bereich von 225–360 nm bestimmt.Eine Methode zur quantitativen Bestimmung der genannten Verbindungen wurde ausgearbeitet, um den Herstellungsprozeß von 2,2Dichinoxalyl, 3,3-Dimethyl-2,2-dichinoxalyl, 2,2-Dipyrazyl und 5,5-Dimethyl-2,2-dipyrazyl aus den entsprechenden Monomeren durch direkte Photometrierung von Proben der Reaktionsgemische, die in einem beliebigen Stadium der Synthese dem Reaktor entnommen wurden, verfolgen zu können.

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Spectrophotometric determination of dehydrocondensation products of pyrazines and quinoxalines

Summary The absorption spectra of the following compounds: quinoxaline, 2,2-diquinoxalyl, 2-methylquinoxaline, 3,3-dimethyl-2-2-diquinoxalyl, pyrazine, 2,2-dipyrazyl, 2-methylpyrazine and 5,5-dimethyl-2,2-dipyrazyl were determined in methanol in the region of 225–360 nm. A method was developed for the quantitative determination of these compounds in order to be able to follow the preparation methods of 2,2-diquinoxalyl, 3,3-dimethyl-2,2-diquinoxalyl, 2,2-dipyrazyl and 5,5-dimethyl-2,2-dipyrazyl from the corresponding monomers through direct photometration of samples of the reaction mixture, which can be taken from the reactor at a selected stage of the synthesis.

     

Electronic structure and models of receptor of monooxygenase inductors from a number of polychlorinated polycyclic compounds. IV. MNDO calculations of halogen-substituted azobenzenes

The electron and geometric structures of the cis and trans isomers of 3,3,4,4-tetrachloroazobenzene (3,3,4,4-TCAB) and the trans isomers of 3,3,5,5-TCAB and 3,3-dichloro-4,4-difluoroazobenzene were calculated by the MNDO method. It was established that the trans isomer, which has a planar structure, is most stable for 3,3,4,4-TCAB. Change in the position of the Cl atoms in the azobenzene, i.e., the transition from 3,3,4,4-TCAB to 3,3,5,5-TCAB, does not lead to appreciable change in the formation energy, the position of the electronic levels, the nature of the frontier orbitals, or the charge distribution in the molecules. This gives reason to suggest that the biological activity of 3,3,4,4-TCAB is due to the metabolism products and not to the action of the substrates themselves.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1797–1801, August, 1990.     

Experimental study of particle-to-liquid mass transfer in two-phase fixed and fluidized beds

Primary experimental results for local particle-to-liquid mass transfer in two-phase fixed and fluidized beds and in free flows are reported. A hypothesis on the mechanism of the effect of turbulent pulsations is suggested.

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9-(2′,5′-Dimethyl-4′-pyridyl)fluorene in syntheses of fluorospirodihydrofuropyridine and pyridofluoranthene

1,2,5-Trimethyl-4-(9-fluorenylidene)piperidine, which is formed by condensation of fluorene with 1,2,5-trimethyl-4-piperidone, is converted catalytically to 9(2,5-dimethyl-4-pyridyl)fluorene, from which 2-methylpyrido[4,5-a]fluoranthene and its demethylated analog were obtained by catalytic dehydrocyclization. Oxidation of 9-(2,5-dimethy1-4-pyridyl)fluorene gave 9-(2,5-dimethyl-4-pyridyl)9-fluorenol and fluorene-9-spiro-4-(6-oxo-2-carboxypyrido[4,5-c]-4-6-dihydrofuran). 6-Methyl-2-phenyl-7-(9-fluorenyl)indolizine was synthesized by the Chichibabin method.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1087–1090, August, 1978.     

Thiazolobenzo-1, 2, 3-thiadiazoles and derived cyanine dyes

The following tricyclic heterocyclic compounds are synthesized: 2-methylthiazolov (5, 4-e) benzo-1, 2, 3thiadiazole, 2-methylthiazolo (4, 5-e) benzo-1, 2, 3-thiadiazole, 2-methylthiazolo (4, 5-g) benzo-1, 2, 3-thiadiazole, and 2-methylthiazolo (5, 4-g) benzo-1, 2, 3-thiadiazole. The quaternary salts of these bases are used to prepare symmetrical and unsymmetrical trimethinecyanines and dimethinemercocyanines containing N-ethylrhodanine residues. The absorption maxima of these dyes are shifted toward the long-wave region as compared with the corresponding thiacyanines.     

Diazabicycloalkanes with nitrogen atoms in bridgehead positions. 16. Synthesis and properties of benzo[b]-1,4-diazabicyclo[2.2.2]octene and dibenzo[b,e]-1,4-diazabicyclo[2.2.2]octadiene,containing primary aromatic amino acids

4-Aminobenzo[1,2-b]-1,4-diazabicyclo[2.2.2]octene and 4-aminodibenzo[1,2-b, e]-1,4-diazabicyclo[2.2.2]octadiene have been prepared by cyclization reactions of N--chloroethyl derivatives of 1,2,4-triaminobenzene and aminophenazine, and subsequent catalytic hydrogenation of the corresponding 4-nitrobenzo[1,2-b]-1,4-diazabicyclo[2.2.2]octene and 4-benzylaminodibenzo[1,2-b,e]-1,4-diazabicyclo[2.2.2]-octadiene. Using the conversion of these compounds to azides as an example, we have demonstrated the feasibility of applying these primary aromatic amines for the synthesis of derivatives of these heterocycles.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 831–837, June, 1988.     

Cyclization reactions of nitriles. 28. Synthesis and reactions of 3β-acetoxy-2′-methyl-5′-cyanoandrost-5-eno[17,16-c]pyridine-6′ (1′H)-thione

3-Acetoxy-2-methyl-5-cyanoandrost-5-eno[17,16-c]pyridine-6(1H)-thione was obtained by thiylation of 16-dicyanomethyl-3-hydroxypregn-5-en-20-one acetate, and its alkylation by chloroacetonitrile and phenacyl bromide was studied. The same thione was also synthesized by treating the corresponding 6-bromo-2-methyl-5-cyanoandrost-5-eno[17,16-c]pyridine with urea.Communication 27, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 943–946, July, 1988.     

Organodimagnesium derivatives of thiophene. 3. Synthesis of an organodimagnesium derivative of hexabromo-2,2′-dithienyl and its reaction with oxalic acid esters

It was established that the reaction of hexabromo-2,2-dithienyl with magnesium in the presence of ethyl bromide gives an organodimagnesium derivative, which reacts with oxalic acid esters to give 3,3,4,4-tetrabromo-5,5-dithienyl-diglyoxalic acid esters. Reduction of the latter with ethylmagnesium bromide leads to 3,3,4,4-tetrabromo-5,5-dithienyl-2,2-diglycolic acid esters.See [1] for Communication 2.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 468–470, April, 1981.     

Dimerization of N-methylanabasine in the presence of metallic sodium

In a study of the dimerization of N-methylanabasine in the presence of metallic sodium under conditions for the dimerization of pyridine, it was found that the reaction does not take place at room temperature while at 50–70° C it leads to the formation of,-di(1-methylpiperid-2-yl)-,-bipyridyl. Oxidation of the latter yielded 4,4-bipyridyl-5, 5-dicarboxylic acid, the decarboxylation of which gave,-bipyridyl.     

Zur gruppentheoretischen Bestimmung der Atomzustände in Ligandenfeldern

Zusammenfassung Es wird vorgeschlagen, die Bezeichnungen weak-field-Methode bzw. strong-field-Methode durch (L)-Methode bzw. ()-Methode zu ersetzen.Nach einer kurzen Einführung in die ()-Methode wird mit den Mitteln der Gruppen-und Darstellungstheorie eine Formel abgeleitet, mit deren Hilfe man schnell Rasse und Multiplizität der Terme eines Komplexions in der ()-Methode angeben kann. Einige Spezialfälle dieser Formel und die systematische Bestimmung der ()-Funktionen werden erörtert.

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It is suggested that the misleading designations weak field method and strong field method be replaced by (L) method and () method, respectively.Following a brief introduction to the () method an equation is derived by group theoretical means which leads to rapid classification of the () terms. Several special cases and short cuts are discussed as well as the systematic determination of the () functions.

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Résumé Le remplacement des termes «méthode du champ faible» et «méthode du champ fort» par «méthode (L)» et «méthode ()» est proposé.Après une introduction dans la méthode () une formule est dérivée à l'aide de la théorie des groupes et des représentations, qui donne la représentation irréductible et la multiplicité des termes d'un ion complexe dans le cadre de la méthode (). Quelques cas spéciaux de cette formule et la détermination systématique des fonctions (/gG) sont discutés.

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Ich danke Herrn Professor Dr. H. Hartmann für den Hinweis auf das vorliegende Problem und der Deutsehen Forschungsgemeinschaft für ein Stipendium.     

Investigations of 2,3′-biquinolyl. 8. Reduction of 1-alkyl-3-(2-quinolyl)-quinolinium halides with sodium borohydride

Reduction of 1-alkyl-3-(2-quinolyl)quinolinium halides with sodium borohydride leads to 1-alkyl-1,2-dihydro-2,3-biquinolyls which, except for the ethoxycarbonyl derivative, undergo rearrangement to 1-alkyl-1,4-dihydro-2,3-biquinolyls. The last can be synthesized by the alkylation of the corresponding 1,4-dihydro-2,3-biquinolyls under conditions of interphase catalysis and in the system KOH-DMSO.For Communication 7, see [1].Stavropol' State University, Stavropol' 355009, Russia; nauka@stavsu.ru. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1084–1087, August, 2000.     

Soluble polysaccharides of Rhodotorula flava

Conclusions 1. Xanthalin has been shown to have the structure of 2, 2-dimethyl-3, 4,-diangeloyloxy-3, 4-dihydropyrano-5, 6:6, 7-coumarin on the basis of the preparation of a number of derivatives and cleavage products.2. The following products of the alkaline hydrolysis of xanthalin have been isolated and characterized for the first time: (±)-3, 4-dihydroxy-3, 4-dihydroxanthyletin (isokhellactone), C₁₄H₁₄O₅, with mp 213–215° C and (–)-trans-3-hydroxy-4-methoxy-3, 4-dihydroxanthyletin (isomethylkhellactone, C₁₅H₁₆O₅, with mp 136.5–138° C and [] _D ²⁰ –47.7 (ethanol).Khimiya Prirodnykh Soedinenii, Vol. 6, No. 1, pp. 14–19, 1970     

Nitration,amination, and halogenation of Di-O-methylphloracetophenone

Chlorination of the title compound gave 5- and 3-chloro-2-hydroxy-4,6-dimethoxyacetophenone. The nitration of its acetate, followed successively by reduction, diazotization, and reaction with cuprous chloride, gave the 3-substituted series, 2-acetoxy-4,6-dimethoxy-3-nitroacetophenone, 3-amino-2-hydroxy-4,6-dimethoxyacetophenone, and 3-chloro-2-hydroxy-4,6-methoxyacetophenone, respectively. The orientation of substituents in the products was proved. The amino and chloro members of the isomeric 5-substituted series were availablevia 2-hydroxy-4,6-dimethoxy-5-phenylazoacetophenone, the product of the reaction of the title compound with benzenediazonium chloride.

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Nitrierung, Aminierung und Halogenierung von Di-O-methylphloracetophenon

Zusammenfassung Chlorierung der Titelverbindung gab 5- und 3-Chlor-2-hydroxy-4,6-dimethoxyacetophenon. Die Nitrierung des Acetats, gefolgt von Reduktion, Diazotierung und Reaktion mit CuCl ergab die 3-substituierte Reihe: 2-Acetoxy-4,6-dimethoxy-3-nitroacetophenon, 3-Amino-2-hydroxy-4,6-dimethoxyacetophenon und 3-Chlor-2-hydroxy-4,6-dimethoxyacetophenon. Die Orientierung der Substituenten wird diskutiert. Die Amino- und Chlorderivate der isomeren 5-substituierten Reihe sind über 2-Hydroxy-4,6-dimethoxy-5-phenylacetophenon zugängig, dem Produkt der Reaktion der Titelverbindung mit Phenyldiazoniumchlorid.

     

The Mannich reaction with 2-methyl-5-vinylpyridine

1,3-Bis(dimethylamino)-2-(5-vinyl-2-pyridyl)propane and 2-(-dimethylaminoethyl)-5-vinylpyridine were prepared by the aminomethylation of 2-methyl-5-vinylpyridine. These Mannich bases have been transformed into 1-dimethylamino-2-(5-vinyl-2-pyridyl)-1-propene and 2,5-divinylpyridine by the decomposition of their quaternary salts.     

Untersuchung des Zerfalls verschiedener Azoinitiatoren in Lösung

The decomposition of various symmetric and unsymmetric azo-initiators (1,1-dichloro-1,1-diphenyl-1,1-azoethane, 2,2-dichloro-2,2-azopropane, 1,1-dichloro-1,1-azocyclohexane, 2,2-diacetoxy-2,2-azopropane, 1,1-diacetoxy-1,1-diphenyl-1,1-azoethane, 1,1-diacetoxy-1,1-azocyclohexane, 2,2-dipropionoxy-2,2-azopropane, 2,2-dicapronoxy-2,2-azopropane, 4,4-dimethyl-1,4-azobutyrolactone, azoisobutyronitrile, 2-t-butylazo-2-cyanobutan, 2-t-bytylazo-1-cyanocyclohexan) in solution was studied in dependence of temperature. Volumetry and differential-scanning-calorimetry (DSC) were used to determine decomposition rates; first order kinetics was found in all cases.

     

Synthetic studies in the field of chlorobium chlorophyll

By the condensation of -halogenomethyl derivatives of pyrroles with -unsubstituted pyrroles the synthesis of the following unsymmetrical dipyrrolylmethanes has been effected: 5-benzyloxycarbonyl-5-ethoxycarbonyl-3, 3-di(-methoxycarbonylethyl)-4,4-dimethyl-2,2-dipyrrolylmethane (IIIa), 5-benzyloxycarbonyl-5-ethoxycarbonyl-3-(-methoxycarbonylethyl)-4, 4-diniethyl-3-n-propyl-2,2-dipyrrolylmethane(IIIb), 3-acetyl-5-benzyloxycarbonyl-4-ethyl-5-methoxycarbonyl-3, 4-dimethyl-2,2-dipyrrolylmethane (IIIc), and 3-bromo-5-benzyloxycarbonyl-4-ethyl-5-methoxycarbonyl-3, 4-dimethyl-2,2-dipyrrolylmethane (IIId). Hydrogenation of the unsymmetrical dipyrrolylmethanes IIIa, b, c, and d has given the corresponding monocarboxylic acids IVa, b, c, and d. The formylation of the dipyrrolylmethanemonocarboxylic acid IVa has given 5-ethoxycarbonyl-5-formyl-3,3-di(-methoxycarbonylethyl)-4, 4-dimethyl-2,2-dipyrrolylmethane (V).For communication II, see [1].Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 6, No. 8, pp. 1045–1047, August, 1970.     

Synthesis of 2-O-ethyl analogues of 3′-azido- and 3′-fluoro-2′,3′-dideoxyuridines and evaluation of their biological activity against HIV

Summary 2-O-Ethyluracil and 2-O-ethylthymine were silylated with 1,1,1,3,3,3-hexamethyldisilazane and condensed in the presence ofTMS triflate with 2,3-dideoxy-3-fluoro-D-erythro-pentofuranoside, 3-azido-2,3-dideoxy-D-erythro-pentofuranoside, and 2,3-dideoxy-3-phthalimido--D-erythro-pentofuranose derivatives to give the corresponding 2-O-ethyl nucleosides. Deprotection with saturated methanolic ammonia afforded the 2,3-dideoxy-3-fluoro-2-O-ethyluridines, whereas 3-azido-2,3-dideoxy-3-O-ethyluridine was obtained by deprotection with tetrabutylammonium fluoride in tetrahydrofuran. 3-Amino-2,3-dideoxy-3-O-ethyluridine could be obtained only by treatment of the corresponding 3-azido nucleoside with triphenylphosphine in pyridine. 3-Deoxy-2-O-ethyl-3-fluorothymidine (6b) showed moderate activity against HIV-1.

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Synthese von 2-O-Ethyl-Analogen von 3-Azido- und 3-Fluor-23-dideoxyuridinen und Bestimmung ihrer biologischen Aktivität gegenüber HIV

Zusammenfassung 2-O-Ethyluracil und 2-O-Ethylthymin wurden mit 1,1,1,3,3,3-Hexamethyldisilazan silyliert und in Gegenwart vonTMS-triflat mit 2,3-Dideoxy-3-fluoro-D-erythro-pentofuranosid, 3-Azido-2,3-dideoxy-D-erythro-pentofuranosid und 2,3-Dideoxy-3-phthalimido--D-erythro-pentofuranosederivaten zu den entsprechenden 2-O-Ethyl-Nucleosiden umgesetzt. Entfernung der Schutzgruppe mit gesättigter methanolischer Ammoniaklösung lieferte 2,3-Dideoxy-3-fluor-2-O-ethyluridin; 3-Azido-2,3-dideoxy-3-O-ethyl-uridin wurde durch Entschützung mit Tetrabutylammoniumfluorid in Tetrahydrofuran erhalten. 3-Amino-2,3-dideoxy-3-O-ethyl-uridin konnte nur durch Behandeln des entsprechenden 3-Azido-Nucleosids mit Triphenylphosphin in Pyridin hergestellt werden. 3-Deoxy-2-O-ethyl-3-fluor-thymidin (6b) zeigt geringe Aktivität gegenüber HIV-1.

     

Synthesis of some 5′-O-amino acid derivatives of uridine as potential inhibitors ofUDP-glucuronosyltransferase

Summary In an attempt to develop potential inhibitors ofUDP-glucuronosyltransferase, some 5-O-amino acid derivatives of uridine were synthesized. N-protectedL-amino acids were coupled at the 5-O-position of 2,3-O-isopropylideneuridine by esterification employing the method of symmetrical anhydrides in presence of 4-dimethylaminopyridine, 5-O-(N-benzyloxycarbonyl-O-tert.butyl-L-threonl)-23-O-isopropylideneuridine (1), 5-O-(N-tert.butyloxycarbonyl-O-benzyl-L-seryl)-2,3-O-isopropylideneuridine and (2), 5-O-(N-tert.butyloxycarbonyl-L-valyl)-2,3-O-isopropylideneuridine (3), and 5-O-(N-tert.butyloxycarbonyl-L-valyl)-2,3-O-isopropylideneuridine (4) were obtained in good yield after column chromatography on silica gel. The treatment of2 withTFA/CH₂Cl₂ (6:1) at room temperature for 30 min led to a selective removal of theBoc group without deblocking of the 2,3-O-isopropylidene group of uridine. Treatment of2 withTFA/H₂O (5:1) at room temperature for 1 h, however, released bothBoc and 2,3-isopropylidene groups. TheZ group of1 was deprotected by catalytic hydrogenolysis over 10% Pd/C/ammonium formate.

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Synthese von 5-O-Aminosäurederivaten des Uridins als potentielle Inhibitoren derUDP-Glukuronosyl-Transferase

Zusammenfassung In einem Versuch, potentielle Inhibitoren derUDP-Glukuronosyl-Transferase zu entwickeln, wurden einige 5-O-Aminosäurederivate des Uridins synthetisiert. N-GeschützteL-Aminosäuren wurden durch Veresterung mit der 5-O-Position des 2,3-isopropylidenuridins gekuppelt (Methode der symmetrischen Anhydride in der Gegenwart von 5-Dimethylaminopyridin). Solcherweise wurden 5-O-(N-Benzyloxycarbonyl-O-tert.butyl-L-threonly)-2,3-O-isopropylidenuridin (1), 5-O-(N-tert.Butyloxycarbonyl-O-benzyl-L-seryl)-2,3-O-isopropylidenuridin (2), 5-O-(N-tert.Butyloxycarbonyl-L-leucyl)-2,3-O-isopropylidenuridin (3) und 5-O-(N-tert.Butyloxycarbonyl-L-valyl)-2,3-O-isopropylidenuridine (4) nach Säulenchromatographie (Kieselgel) in guter Ausbeute hergestellt. Die Behandlung von2 mitTFA/CH₂Cl₂ (6:1) bei Zimmertemperatur (30 min) führte zu einer selektiven Abspaltung derBoc-Gruppe ohne Deblockierung der 2,3-O-Isopropylidengruppe des Uridins. Eine Behandlung von2 mitTFA/H₂O (5:1) bei Zimmertemperatur für 1 Stunde führte hingegen zur Abspaltung sowohl derBoc als auch der 2,3-O-Isopropylidengruppe. DieZ-Gruppe von1 wurde durch katalytische Hydrogenolyse auf 10% Pd/C/Ammoniumformiat abgespalten.

     

1,1′,2,2′,6,6′-Hexaphenyl-4,4′-bipyridinium cation radical

Aniline reacts with 2,2,6,6-tetraphenyl-4,4-bipyrilium perchlorate to form 1,1,2,2,6,6-hexaphenyl-4,4-bipyridine perchlorate. A relatively stable cation radical is formed in the first stage of electrochemical reduction of this compound, which has been examined by ESR, where there are splittings from two nitrogen nuclei and the four protons in the 3,3,5,5 positions: a_N=0.38; a_H=0.14 mT.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, No. 1, pp. 61–64, January–February 1992.     

1,1′-Disubstituted 2,2′-di(n-perfluoropropyl)-5,5′-bibenzimidazolyls

The synthesis of 4,4-di(methylamino)- and 4,4-dianilino-3,3-diaminobiphenyls is described. The condensation of the tetraaminobiphenyls mentioned with phenyl perfluorobutyrate has given, respectively, 1,1-dlmethyl- and 1,1-diphenyl-2,2-(n-perfluoropropyl)-5, 5-bibenzimidazolyls. A study of the thermal stability of the 2-perfluoroalkylbenzimidazoles has shown that the replacement of the hydrogen of the imino group in these compounds by a methyl or a phenyl radical considerably increases their heat stability.