The possibility of preparing 1,2,3,4,6,7,8,9-octahydro-5H-pyrrolo[3,2-c:4,5-c']dipyridines using the Piloty-Robinson reaction has been studied under various conditions. A novel method is proposed for the synthesis of the aromatic 3,6-diazacarbazole (5H-pyrrolo[3,2-c:4,5-c']dipyridine) from 2,8-dibenzoyl-1,2,3,4,6,7,8,9-octahydro-5H-pyrrolo[3,2-c:4,5-c']dipyridine obtained for the first time by the Piloty- Robinson method under thermal conditions.
Convenient preparative methods have been developed for the reduction of the active substance of the medicinal preparation Dimebon (2,8-dimethyl-5-[2-(6-methylpyrid-3-yl)ethyl]-1,2,3,4-tetrahydro-γ-carboline) to the corresponding racemic cis- and trans-1,2,3,4,4a,9b-hexahydro derivatives, distinguished by a high degree of stereoselectivity. The structures of the obtained diastereomeric hexahydro-γ-carbolines were confirmed by various physicochemical methods, including X-ray structural analysis.
A chemonuclear method of synthesis is proposed for obtaining difficultly available phenyl-substituted derivatives of quinoline labeled with tritium. The ion-molecule reaction of free phenyl cations, generated on β-decay of tritium, with the nucleophilic centers of heterocyclic compounds is the basis of the synthesis. The onium derivatives synthesized possess significant inhibitory antimicrobial activity and are promising for a detailed study of the reaction mechanisms and metabolic processes using radioactive indicators.
The interaction of 6-allylthio-4-imino-1-methyl-3-methylthio-5-phenyl-1,5-dihydro-4H-pyrazolo[3,4-d]-pyrimidine with bromine leads to the formation of 8-bromomethyl-4-imino-1-methyl-3-methylthio-5-phenyl-4,5,7,8-tetrahydro-1H-pyrazolo[4,3-e][1,3]thiazolo[3,2-a] pyrimidinium tribromide.
Treatment of exo-3,4-diazatricyclo[5.2.1.0 2,6 ]dec-4-ene with methyl acrylate, acrylonitrile, ethylene oxide, acetic acid and nitrosonium cation gave a series of 3-N-substituted exo-3,4-diazatricyclo[5.2.1.0 2,6 ]dec-4-enes.
Reaction of 1-alkyl-3-alkylaminopyrrole-2,5-diones with primary arylamine hydrochlorides in methanol or DMSO gives 1-alkyl-3-arylaminopyrrole-2,5-diones which could also be obtained from the reaction of arylaminofumarates with primary aliphatic amines.
Data on methods for the synthesis of isoindolo[2,1-a]benzimidazole and its derivatives and their chemical characteristics are reviewed. Data from quantum-chemical calculations of certain structures are presented. Possible practical applications of the compounds are indicated.
A simple and convenient method is proposed for the synthesis of 2-amino-5-hydroxymethylthiazolines with various substituents in the amino group, which is based on hydrolysis of the corresponding 5-halomethyl derivatives of thiazoline in the presence of divalent lead oxide.
We have studied the reactions of alkylation, oxidation, and hydrolysis of 3-aryl-2-thioxoquinazolin-4-ones. Alkylation in an alkaline medium occurs exclusively at the sulfur atom. Oxidation by hydrogen peroxide leads to formation of 3-arylquinazoline-2,4-diones. The latter are also obtained in base or acid hydrolysis of the synthesized S-alkyl derivatives. When 3-aryl-2-thioxoquinazolin-4-ones are reacted with iodine, we obtain the disulfides, while the reaction with chlorine in hydrochloric acid leads to 2-chloroquinazolin-4-ones. Studying the mass spectrometric behavior of the compounds obtained made it possible to observe in the gas phase ring-chain isomerization of the heterocyclic ring, and also S-N migration of the propargyl radical in molecular ions of the S-propargyl derivatives.
Isomeric azidostyrylquinolines with a 4-azidostyryl group in position 2 or 4 of the quinoline ring have been synthesized. In the neutral form the azidostyrylquinolines absorb in the near UV but the protonated species absorb in the short wavelength region of the visible spectrum. In both forms the azides are lightsensitive and decompose under the influence of light with a quantum yield close to 1.
3-Hydroxy-3-(2-oxoethyl)-6-phenyl-2,3-dihydropyridazin-4(1H)-ones were obtained by the reaction of methyl 3-oxo-5-phenylfuran-2(3H)-ylideneacetate or 2-[2-(4-chlorophenyl)-2-oxoethylidene]-5-phenylfuran-3(2H)-one with benzoic or p-nitrobenzoic isopropylidenehydrazides. Equilibrium C (5) H and C (5) H 2 tautomeric forms were detected in solutions of the 4-chlorophenyl derivatives in DMSO-d 6 .
