Synthesis of pyrido [1',2':4,3 ]-s-triazolo[1,5-a]-pyrimidinium salts

Pyrido[l',2':4,3]-s-triazolo[1,5-a]pyrimidinium perchlorates were obtained by the condensation of 3-amino-s-triazolo[4,3-a]pyridinium perchlorate with -diketones, -chlorovinyl ketones, -chlorovinyl aldehydes, and 1,1,3,3-tetraethoxypropane. Unsymmetrical -diketones, -chlorovinyl ketones, and -chlorovinyl aldehydes in this reaction give mixtures of isomeric products that differ with respect to the position of the substituents in the pyrimidine ring. The structures of the reaction products and their ratios in the reaction mixture were determined by means of the PMR spectra.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1433–1435, October, 1971     

2,3-Diphenylthiazolo[3,2-a]pyrimidinium salts

The corresponding 2,3-diphenyl[3,2-a]pyrimidinium salts were obtained by the condensation of 4,5-diphenyl-2-aminothiazole perchlorate with -diketones, -chlorovinyl ketones, -chlorovinyl aldehydes, and 1,1,3,3-tetraethoxypropane. The PMR spectra were used to prove the structures of the compounds obtained, particularly to select the structures of the isomeric salts obtained in the condensation with unsymmetrical -diketones, -chlorovinyl ketones, and -chlorovinyl aldehydes. As a rule, the latter give one isomer — the -unsubstituted (relative to the bridge nitrogen atom) derivative.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 629–631, May, 1972.     

Reaction of ammonia with β,β′-dithioalkyl-α,α′-divinyl ketones

Conclusions Syntheses are reported for ,-dithioalkyldivinyl ketones, which react with ammonia to give -amino--thioalkyldivinyl ketones.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2414–2415, October, 1988.The authors thank A. M. Kachurin for assistance in taking the spectra.     

IR spectra of oxygen adsorbed on SnO2

IR spectra of oxygen adsorbed on SnO₂ with and without lattice defects have been studied. At low temperatures oxygen is adsorbed on defect SnO₂ in two forms of O ₂ ^– . This supports the earlier results obtained by ESR. The low-temperature forms of adsorbed oxygen (unrevealed in ESR spectra) were detected on defectless SnO₂. High-temperature forms of adsorbed oxygen appear in the IR-spectra as bands due to vibrations of the cation-oxygen bond.

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- SnO₂. , O ₂ ^– , . SnO₂ .

     

Application des methodes thermoanalytiques a l'etude des solides divises

Résumé L'application des méthodes thermoanalytiques à l'étude des solides finement divisés s'avère dans certains cas plus efficace que celle de la diffraction des rayons X. A propos d'oxydes constitués de cristallites de quelques dizaines d'angströms, nous montrons comment la TG et l'ATD ont permis une caractérisation de phases. Celles-ci, qualifiées généralement et hâtivement «d'amorphes» n'avaient pu, pour la plupart, être mises en évidence jusque là.

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The application of thermoanalytical methods to study finely-divided solids is found more efficient in some cases than X-ray diffraction. For oxides whose crystallite size is in the range of a few ten angströms, it is shown how TG and DTA have allowed phase identifications. The majority of these phases, called generally and prematurely amorphous had not previously been yet reported.

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Zusammenfassung Der Einsatz thermoanalytischer Methoden zur Untersuchung fein verteilter Feststoffe erweist sich in gewissen Fällen als wirksamer als die Anwendung der Röntgendiffraktion. An Hand von Oxiden, welche aus Kristalliten der Grössenordnung einiger zehn Angström bestehen, wird gezeigt, in welcher Weise die Thermogravimetrie und die Differentialthermoanalyse eine Charakterisierung der Phasen gestatten. Die im allgemeinen voreilig als amorph bezeichneten Phasen konnten größtenteils bis jetzt nicht nachgewiesen werden.

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, - , , , . , ** , , . , , .

     

Dichlorocyclopropanation of chloro-substituted vinyl phenyl ethers

Conclusions The reaction of chloro-substituted vinyl phenyl ethers with dichlorocarbene generated by the thermolysis of phenyl(trichloromethyl)mercury leads to the corresponding gem-dichlorocyclopropyl derivatives while the reaction of cis--chlorovinyl phenyl ether with chloroform and alkali under phase transfer catalysis conditions gives -trichloromethyl--chloroethyl phenyl ether.Deceased.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 222–224, January, 1985.     

Comparative study on inclusion complexations of antiinflammatory drug flurbiprofen with β-cyclodextrin and methylated β-cyclodextrins

Abstruct Some physicochemical properties of methylated -cyclodextrins, i.e., heptakis(2,6-di-O-methyl)--cyclodextrin (DM--CyD) and heptakis(2,3,6-tri-O-methyl)--cyclodextrin (TM--CyD) were compared with those of natural -cyclodextrin (-CyD). Inclusion behaviors of -CyD and methylated -CyDs in water and in solid state were studied by solubility analysis, spectroscopies (UV, CD,¹³C-NMR and IR), X-ray diffractometry and thermal analysis, using an antiinflammatory drug flurbiprofen (FP) as a guest molecule. The spectral data suggest that the inclusion mode of FP-TM--CyD is somewhat different from those of FP--CyD and FP-DM--CyD. The solid complexes of FP with - and methylated -CyDs were obtained in molar ratio of 11, and their dissolution behavior and release from suppository base were examined. The data are presented suggesting that DM--CyD is particularly useful for improving the pharmaceutical properties of FP in various dosage forms.     

Ultrasonic study of the molecular encapsulation and the micellization processes of dodecylethyldimethylammonium bromide-water solutions in the presence of β-cyclodextrin or 2,6-di-o-methyl-β-cyclodextrin

Aqueous solutions of -cyclodextrin (-CD) or 2,6-di-o-methyl--cyclodextrin (DM--CD) and dodecylethyldimethylammonium bromide (D₁₂EDMAB) have been studied from speed of sound (u) data at 298.15 K, using a pulse-echo-overlap technique. The molecular encapsulation process of the surfactant monomer into the cyclodextrin cavity and its effect in the micellization process of the surfactant have been analyzed from theu measurements: I) as a function of [D₁₂EDMAB] in the presence of several initial cyclodextrin concentrations (-CD or.DM--CD); II) as a function of [cyclodextrin] (-CD or DM--CD), for an initial micellar solution of D₁₂EDMAB and; III) as a function of the [cyclodextrin]/[surfactant] stoichiometric concentrations. Both inclusion complexes formed (-CDD₁₂EDMAB) and (DM--CDD₁₂EDMAB) have stoichiometries of 11, and their association constantK have been determined using a model proposed in this work, based on the additivity of the different contributions of the involved species to the speed of sound. The apparent critical micellar concentration, cmc^*, of D₁₂EDMAB is found to increase linearly upon the addition of cyclodextrin (-CD or DM--CD). The free surfactant concentration in the micellar region, [D₁₂EDMAB]_f, decreases in the presence of -CD and slightly increases in the presence of DM--CD. The influence of the parcial methylation of the -cyclodextrin (-CDDM--CD) and of the polar head of the surfactant (D₁₂TAB D₁₂EDMAB) on the complextion and micellar parameters are also discussed.Supplementary material available: Tables of speed of sound (14 pages) are available from the authors.     

Reaction of dimethylaminomethylenemalonaldehyde bis-N,O-acetal with ketones. A novel route to N-methylpyrroles

Condensation of the bis-N,O-acetal of amethylarrtinomethylenerrzalonaldehyde with ketones, -dimethylaminovinylketones, and -dimethylaminodienones is accompanied by an unusual intramolecular cyclization to give cross conjugated cyclic or acylic ketones containing an N-methyl pyrrole ring in the - or - and'-positions. This is a novel route to substituted pyrroles. Treatment of the bis-N,O-acetal of dimethylaminomethylenemalonaldehyde with 2-(3'-dimethylaminopropen-2'-ylidene)cyclopentanone gave a polyenyl tris-dimethylaminodiketone.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 117913. Translated from Khimiya Geterotsiklicheskikh Soednenii, No.5, pp. 654–662, May, 1996. Original article submitted February 14, 1996.     

Sodium Dithionite Reduction of 2S,5R-(-)-menthone and R-(+)-pulegone in the Presence of β-Cyclodextrin and Hydroxypropyl-β-cyclodextrin

Menthone on reduction with sodium dithionite,showed a good amount of mentholformation in the water/DMF system, withincreasing -cyclodextrin (-CD)concentration from 47.0% for 0.1 equivalent of-CD to 93.5% for 1 equivalentof -CD. Increasing hydroxypropyl--cyclodextrin(HP-CD) gave higher menthol/neomenthol (M/N) ratiosfrom 2.8 to 3.5. In the case of pulegone,increasing -CD showed an increase in the formationof menthols in thewater/DMF system from 13.3% for 0.1 equivalent of-CD to 78.1% for 1equivalent of -CD with greater proportions ofneomenthol and neoisomenthol.However, HP-CD which showed only marginalenhancement in the formationof menthol from menthone (32.1–41%), exhibiteda greater proportion of mentholformation in the case of pulegone (55.1%).However, the phase-transfer capabilityof HP-CD was not found to be significant.