Vol 53, No 12 (2017)

The review generalizes and systemizes data published over the past 15 years on the synthesis and chemical properties of cycloalka[c]pyridine derivatives that are important intermediate products used in the synthesis of alkaloids, enzyme inhibitors, and drugs for the treatment of cardiovascular diseases and bronchial asthma.

Copper(I)-catalyzed arylation of 14 adamantane-containing amines with iodobenzene, 1-fluoro-4-iodobenzene, 1-iodo-4-(trifluoromethyl)benzene, and 1-iodo-4-methoxybenzene has been studied under the conditions optimized previously. The yields of the N-arylation products have been shown to depend in a complicated manner on the amine structure, steric environment of the amino group, and substituent nature in iodobenzene.

Selenium tetrahalides generated from selenium dioxide and hydrogen halides (HCl, HBr) reacted with hex-1-ene, hept-1-ene, and oct-1-ene at a SeO₂‒alkene molar ratio of 1: 2 to give mixtures of dihalobis-(2-haloalkyl)-λ⁴-selanes (yield 80‒90%) and bis(2-haloalkyl) selenides (yield 5‒12%). Halogenation of the resulting mixtures afforded 85‒93% (calculated on the initial SeO₂) of the corresponding dihalobis(2-haloalkyl)-λ⁴-selanes, and the reduction of the same mixtures with Na₂S₂O₅ gave bis(2-haloalkyl) selenides in 80‒86% yield. In the reaction with a SeO₂‒alkene ratio of 5: 8, pure dihalobis(2-haloalkyl)-λ⁴-selanes were formed in 84‒93% yield. Dichlorobis(2-chloro-2-phenylethyl)-λ⁴-selane was obtained in 72% yield in the reaction of SeO₂‒HCl with styrene.

2,3-Dichlorodecafluorotetralin reacted with ethyl cyanoacetate to give ethyl 2-cyano-2-(6,7-dichlorononafluoro-5,6,7,8-tetrahydronaphthalen-2-yl)acetate which was hydrolyzed to (6,7-dichlorononafluoro-5,6,7,8-tetrahydronaphthalen-2-yl)acetic acid. The latter was treated with PCl₅ on heating to obtain 2,2-dichloro-(6,7-dichlorononafluoro-5,6,7,8-tetrahydronaphthalen-2-yl)acetyl chloride which was converted to 2,3-dichlorononafluoro-6-trifluoromethyl-1,2,3,4-tetrahydronaphthalene by the action of SbF₅. The reduction of 2,3-dichlorononafluoro-6-trifluoromethyl-1,2,3,4-tetrahydronaphthalene with zinc in 1,4-dioxane gave perfluoro-6-methyl-1,4-dihydronaphthalene, and in DMF, perfluoro-2-methylnaphthalene.

Palladium-catalyzed cross-coupling of 5-methyl- and 5,5-dimethyl-3-(prop-2-yn-1-yl)oxolan-2-ones with dihaloarenes (dihaloheteroarenes) gave mixtures of the corresponding mono- and bis-coupling products. The latter can be obtained as the major products by variation of the catalytic system.

The aminolysis of 6-[1-(2,6-difluorophenyl)cyclopropyl]-5-methyl-2-(nitroamino)pyrimidin-4(3H)-one with various amines in butan-1-ol and under solvent-free conditions is successful when the amino group in the reagent is sterically unshielded and the reaction medium is characterized by a high dielectric permittivity. Reactions of the title compound with sterically shielded amines are accompanied by alcoholysis where the amine acts as a base catalyst.

Acetophenones containing a methoxycarbonylamino group in position 2, 3, or 4 of the aromatic ring reacted with phenylglycine in the presence of 2 equiv of iodine and 0.5 equiv of sulfanilic acid in DMSO at 100°C for 6 h to give methyl [2(3,4)-(2-phenyl-1,3-oxazol-5-yl)phenyl]carbamates. The reaction was presumed to involve intermediate formation of methyl [(iodoacetyl)phenyl]carbamate. This was confirmed by the isolation of methyl [2-(iodoacetyl)phenyl]carbamate in the reaction of methyl (2-acetylphenyl)carbamate with iodine in glacial acetic acid and its subsequent transformation to methyl [2-(2-phenyl-1,3-oxazol-5-yl)-phenyl]carbamate.

The effects of temperature, solvent nature, and high hydrostatic pressure on the rate of the reaction of biadamantylidene with 4-phenyl-3H-1,2,4-triazole-3,5(4H)-dione have been estimated. Significant shielding of the C=C double bond in biadamantylidene is responsible for the high entropy and volume of activation. Quantitative yield of the reaction in the temperature range 25‒45°C is related to its exothermicity. The rate of the [2π + 2π]-cycloaddition unexpectedly weakly depends on the solvent polarity, which makes it radically different from the [2π + 2π]-reaction with tetracyanoethylene.

The reaction of 2-bromomethyl-1,3-thiaselenole with sodium ethanethiolate in acetonitrile at 20–25°C (2 h) afforded bis[(Z)-2-(vinylsulfanyl)ethenyl] diselenide in 82% yield. The reaction involves intermediate formation of (Z)-1-[(ethylsulfanyl)selanyl]-2-(vinylsulfanyl)ethene.

Enolizable 1-(tetracyanocyclopropyl)alkanones reacted with aqueous alkali metal hydroxides to give, depending on the alkali concentration, 2-(5-amino-2-alkylidene-4-cyano-2,3-dihydrofuran-3-ylidene)-propanedinitriles or 2-(4-alkyl-3-amino-2-cyano-5-oxo-cyclopent-2-en-1-ylidene)propanedinitriles.

5-Formyl-1H-imidazole-4-sulfonyl chlorides reacted with hydrazine hydrate or alkylhydrazines to give 2,5-dihydroimidazo[4,5-e][1,2,3]thiadiazine 1,1-dioxides.

New biologically active 2H-benzimidazole 1,3-dioxide derivatives, analogs of Sepin-1, have been synthesized starting from benzofuroxan. Electrophilic substitution of hydrogen in the 2H-benzimidazole ring occurs at different positions, depending on the electrophile nature.

3-Aroylpyrrolo[1,2-c][4,1]benzoxazine-1,2,4-triones reacted with salicylaldehyde thiosemicarbazone to give 9-aroyl-8-hydroxy-2-[2-(2-hydroxybenzylidene)hydrazinylidene]-6-(2-hydroxy-phenyl)-1-thia-3,6-diazaspiro[4.4]non-8-ene-4,7-diones.