Aromatic fluorine chemistry. Part 1. 3,4-Difluorobenzoic acid and derivatives via 3,4-difluorobenzotrifluoride

The preparation of 3,4-difluorobenzotrifluoride from 3-4-dichlorobenzotrifluoride by a KF exchange reaction is described. The conversion of 3,4-difluorobenzotrifluoride to 3,4-difluorobenzoic acid and derivatives is also reported.     

Symmetric 3,4-Diacetyl-2,5-dimethoxypyrroles. Heterocyclization of 3,4-Diacetylhexane-2,5-dione with Primary Amines

Russian Journal of General Chemistry -     

Selenium heterocycles. XXXIII. Synthesis of thieno[3,4-b]furan,seleno[3,4-b]furan,thieno[3,4-b]indole and seleno[3,4-b]indole. four novel heterocycles

Starting from the readily available 2-methyl-3-benzoylfuran, 1-phenylthieno[3,4-b]furan and 1-phenyl-seleno[3,4-b]furan were prepared. Also, starting from phenyl 3-methylindol-2-yl ketone and aryl 2-methyl-indole-3-yl ketones a series of substituted thieno[3,4-b]indoles and substituted seleno[3,4-b]indoles were prepared.     

Sulfostyrils. IV. Reactions of 4-keto-3,4-dihydrosulfostyril

The ketone group in 4-keto-3,4-dihydrosulfostyril (I) displays anomalous properties. Its reactions are described; in some reactions it behaved normally, in others it proved quite inert. Attempted oximination of I led to extrusion of the sulfone group with formation of isatin derivatives. Compound I was converted to a tetracyclic indole derivative.     

Potential antitumor agents. III. Synthesis of pyrazolo[3,4-e]pyrrolo[3,4-g]indolizine and 1H-pyrazolo[3,4-e]indolizine derivatives

The preparation of 5-dimethylaminoethyl-4,6-dioxo-1-phenyl-1,4,5,6-tetrahydropyrazolo[3,4-e]pyrrolo-[3,4-g]indolizine, a derivative of the still unknown tetracyclic parent ring pyrazolo[3,4-e]pyrrolo[3,4-g]indolizine, is reported starting from 1-phenyl-5-(1-pyrryl)pyrazole-4-acetonitrile by PPA catalyzed double cyclization of the related oxalylcyanomethyl derivative and subsequent alkylation. The synthesis of 4,5-bis(isopro-pylaminocarbonyloxymethyl) and 4,5-bis-(cyclohexylaminocarbonyloxymethyl) derivatives of 1-phenyl-1H-pyrazolo[3,4-e]indolizine is also described. The new tricyclic and tetracyclic derivatives were tested as potential antitumor agents.     

Reactions of 3,4-epoxy alcohols. New results

The treatment of 5,6-epoxynorbornan-2-ol derivatives with acidic or basic reagents has provided new examples of oxetane formation, particularly a novel dimerization and a cyclization following reversible first order kinetics.     

Chemistry of thienopyridines. XV. Syntheses of thieno [3,4-b] - and thieno[3,4-c] pyridines

Thieno [3,4-b] pyridine (5) was synthesized by means of the successive steps of (a) photochlorination of 2,3-dimethylpyridine to the bis(chloromethyl) compound, (b) condensation with sodium sulfide, (c) oxidation to the sulfoxide, and (d) catalytic dehydration by means of alumina. Thieno[3,4-c]pyridine (6) was obtained in an analogous manner. Spectral properties indicate that 5 and 6 have aromatic character.     

The photolysis of trans-3,4-dimethylcyclopentanone. II. Short Wavelengths

The photolysis of trans-3,4-dimethylcyclopentanone has been investigated in the gas phase at 100°C using light of 206 and 193 nm. The photolytic products are propene, 1,2-dimethylcyclobutane, and the butene isomers. Small quantities of 3,4-dimethylpent-4-enal were also detected. Relative yields of these products were determined as a function of the ketone pressure and also of that of added nitrogen. A mechanism for the photochemical decomposition based on that suggested for the photolysis of cyclopentanone using short wavelength radiation, is consistent with the experimental results and is simpler than that required to account for the long wavelength photolysis reported earlier.     

Chemistry of furazano[3,4-b]pyrazine. 4. 5,6-Dichlorofurazano[3,4-b]pyrazine in cyclization reactions

A method was developed for the production of polycyclic compounds containing the furazano[3,4-b]pyrazine fragment by the reaction of difunctional nucleophiles with 5,6-dichlorofurazano[3,4-b]pyrazine. It was shown that the reaction is affected by the hydrogen chloride acceptor (triethylamine). For Communication 3, see [1]. Latvian Institute of Organic Synthesis, Riga LV-1006. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11. pp. 1561–1564, November, 1997.     

Reaction of 2-Chloropyridine-3,4-dicarbonitrile with Anilines. Synthesis of 2-(Arylamino)pyridine-3,4-dicarbonitriles

Russian Journal of Organic Chemistry - The reaction of 2-chloropyridine-3,4-dicarbonitrile with anilines in propan-2-ol in the presence of N,N- diisopropylethylamine (DIPEA) in a sealed vial at...     

Selenium heterocycles XXVI. Synthesis of theino[3,4-b]benzofuran and selenolo[3,4-b] benzofuran. Two novel heterocycles

Starting from the readily available aryl 3-methyl-2-benzo[b] furyl ketones a series of 3-sub-stituted thieno[3,4-b] benzofurans and 3-substituted selenolo[3,4-b] benzofurans were prepared in high yield. The parent compound, thieno[3,4-b] benzofuran was prepared through the reaction of thioacetamide with 2-chloromethyl-3-formylbenzo[b] furan in moderate yield.     

3,4-Diaminocoumarins

A number of 3,4-diaminocoumarins was obtained by hydrogenation of 3-nitro-4-aminocoumarins. It was established that these compounds exist in the coumarin form, and monoacetylation of the 3-NH₂ group does not shift the tautomeric equilibrium.See [1] for a previous communication.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 316–320, March, 1976.     

Pyrazolo[3,4-b]pyridines. I. Xanthine and isoguanine analogs derived from 1-methylpyrazolo[3,4-b]pyridine

The synthesis of 4,6-dihydroxy-l-methylpyrazolo[3,4-b Jpyridine ( 2 ) and 4-amino-6-hydroxy-1-methylpyrazolo[3,4-b] pyridine ( 3 ) as analogs of xanthine and isoguanine has been accomplished from ethyl 5-amino-1-methylpyrazole-4-carboxylate ( 4 ) and 5-amino-1-methylpyrazole-4-carbo-nitrile ( 6 ), respectively.     

Structure of 3,4-dinitro-3,4-dimethyl-1,1-diphenyl-1-silacyclopentane

Conclusions 3,4-Dinitro-3,4-dimethyl-1,1-diphenyl-1-silacyclopentane in the liquid phase has a half-chair conformation, and in the solid phase, its conformation is described by a form intermediate between the half-chair and the envelope conformation.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2731–2736, December, 1985.