Том 53, № 1 (2017)

Alkylation of N,N-dialkylcarboxamides with 1,3-dehydroadamantane has been accomplished for the first time. The reaction involves the C–H bond in the α-position with respect to the carbonyl group and provides a convenient one-step preparation of substituted carboxylic acid amides containing an 1-adamantyl substituent and a pharmacophoric group in the amide moiety.

The dynamic structure of styrene has been studied with the goal of obtaining detailed information on the internal rotation parameters. A potential energy surface has been constructed for the rotation of the vinyl group about the single bond in terms of the second-order Møller–Plesset perturbation theory with aug-cc-pvtz basis functions, and conformational dependences of ⁿJ_HH have been calculated at the FPT DFT (B3LYP) level of theory with basis functions of the same type. The vibration-averaged coupling constants have been compared with the experimental values reliably determined in this work. A high efficiency of the proposed dynamic model for structural studies of organic molecules with ultrafast internal rotation dynamics has been demonstrated.

A new photochromic fulgimide, (E)-1-(anthracen-9-ylmethyl)-3-[1-(5-methoxy-2-methyl-1-phenyl-1H-benzo[g]indol-3-yl)ethylidene]-4-(propan-2-ylidene)pyrrolidine-2,5-dione, has been synthesized and found to exhibit fluorescence. The structure of this compound and intermediate fulgenates and amidofulgenic and fulgenic acids has been determined by electronic and vibrational spectroscopy, ¹H and ¹³C NMR, and mass spectrometry. The amidofulgenic and fulgenic acids are capable of undergoing photoinduced reversible Z/E isomerization with respect to the C=C bond without subsequent cyclization, whereas fulgenates are converted to the corresponding cyclic structures. The new fluorescent fulgimide is transformed into the colored nonfluorescing cyclic isomer under UV irradiation. The reverse ring opening under visible light irradiation restores the fluorescence properties, which makes this compound a molecular fluorescence switch.

A procedure has been developed for the conversion of the CS gas [2-(2-chlorobenzylidene)-malononitrile] to new 3-cyanocoumarin derivatives, 4-(2-chlorophenyl)-2-oxo-2H-chromene-3-carbonitriles. Study of the optical properties of the synthesized compounds has revealed strong fluorescence in the violet and blue regions.

2,2-Dimethyloxane-4-carbaldehyde reacted with ethyl cyanoacetate to give ethyl 2-cyano-3-(2,2-dimethyloxan-4-yl)prop-2-enoate whose reaction with isopropylmagnesium bromide afforded ethyl 2-cyano-3-(2,2-dimethyloxan-4-yl)-4-methylpentanoate. Elimination of the ester group from the latter led to the formation of 3-(2,2-dimethyloxan-4-yl)-4-methylpentanenitrile.

The reaction of 2,6-bis(hydroxyimino)cyclohexan-1-one with aldehydes and ammonia afforded 2-substituted 4-hydroxyimino-4,5,6,7-tetrahydro-1H-benzimidazol-1-ols which were hydrolyzed to 1-hydroxy- 2-R-1,5,6,7-tetrahydro-4H-benzimidazol-4-ones. The N-hydroxy group in the latter can readily by removed by the action of chloroacetone in the presence of a base (potassium carbonate or triethylamine); as a result, 2-substituted 1,5,6,7-tetrahydro-4H-benzimidazol-4-ones were obtained.

The oxidation of methyl (4-acetylphenyl)carbamate with selenium dioxide in dioxane–water (30: 1) gave methyl [4-(oxoacetyl)phenyl]carbamate whose condensation with ethyl acetoacetate or diethyl malonate and hydrazine hydrate afforded ethyl 3-methyl-6-[4-(methoxycarbonylamino)phenyl]pyridazine-4-carboxylate and methyl {4-[5-(hydrazinecarbonyl)-6-oxo-1,6-dihydropyridazin-3-yl]phenyl}carbamate, respectively. The reaction of methyl [4-(oxoacetyl)phenyl]carbamate with o-phenylenediamine in dimethylformamide–ethanol on heating led to the formation of methyl [4-(quinoxalin-2-yl)phenyl]carbamate. Methyl {4-(5,7-dioxo- 4,4a,5,6,7,8-hexahydropyrimido[4,5-c]pyridazin-3-yl)phenyl}carbamate and methyl {4-(5-oxo-7-sulfanylidene- 4,4a,5,6,7,8-hexahydropyrimido[4,5-c]pyridazin-3-yl)phenyl}carbamate were synthesized by reactions of methyl [4-(oxoacetyl)phenyl]carbamate with barbituric and thiobarbituric acids, respectively, and hydrazine hydrate in the presence of zirconyl chloride octahydrate at room temperature.

6,7-Difluoroquinoxalin-2-one reacted with indoles, 5,5-dimethylcyclohexane-1,3-dione, 3-methyl-1-phenyl-1H-pyrazol-5(4H)-one, resorcinol, and pyrogallol on heating in acetic acid to give products of hydrogen substitution in the heterocyclic fragment. Heating of 6,7-difluoro-3-(1H-indol-3-yl)quinoxalin-2(1H)-ones with N-methylpiperazine gave the corresponding 7-(4-methylpiperazin-1-yl) derivatives.

The reaction of 1,2,4-triazine-5-carbonitriles with 4-(cyclohex-1-en-1-yl)morpholine under solventfree conditions has been found to follow two pathways: aza-Diels–Alder reaction and unexpected decyanation of the initial nitriles. The scope of the revealed decyanation reaction has been roughly estimated.

Reactions of poststerone with methyl iodide, allyl bromide, and propargyl bromide in lithium–ammonia solution resulted in its completely stereoselective 7α-alkylation accompanied by reduction of the 20-oxo group with formation of equimolar amounts of 20R- and 20S-hydroxy derivatives. The reaction of poststerone with excess allyl bromide afforded 7,7-bis-allyl 20R- and 20S-alcohols at a ratio of 3: 1. The reduction of the 20-oxo group in the alkylation of poststerone with excess propargyl bromide led to the formation of an equimolar mixture of Δ⁸⁽¹⁴⁾- and Δ⁸⁽⁹⁾-isomers with exclusive S configuration of C²⁰.

Reactions of caryophyllene oxide with ethane-1,2-dithiol and 2-sulfanylethanol in the presence of Lewis acids (BF₃ · Et₂O and ZnCl₂) as catalyst afforded addition products with caryophyllane and clovane structures.

Aromatization of 2-methyl-6-(methylsulfanyl)-5-phenyl-2,3-dihydropyridine in DMSO in the presence of potassium tert-butoxide is accompanied by dimerization with formation of a mixture of 6-methyl-2-(methylsulfanyl)-3-phenylpyridine (major product), 2-methyl-6-(methylsulfanyl)-5-phenyl-2,3,4,5-tetrahydropyridine, and 2-methyl-4-[2-methyl-6-(methylsulfanyl)-5-phenyl-2,3-dihydropyridin-3-yl]-6-(methylsulfanyl)- 5-phenyl-2,3,4,5-tetrahydropyridine.

The reaction of ethyl 2-[2-oxo-5-phenylfuran-3(2H)-ylideneamino]-4,5,6,7-tetrahydro-1-benzothiophene- 3-carboxylate with primary amines (RNH₂) in toluene under reflux led to the formation of the corresponding ethyl 2-[(1-R-5-hydroxy-2-oxo-5-phenyl-2,5-dihydro-1H-pyrrol-3-yl)amino]-4,5,6,7-tetrahydro- 1-benzothiophene-3-carboxylates. The product structure was determined by X-ray analysis.

1-Alkyl-3-(2,2-dichlorocyclopropyl)-1H-pyrazoles have been synthesized by cyclopropanation of the corresponding 3-vinylpyrazoles with dichlorocarbene generated from chloroform or sodium trichloroacetate and tested for insecticidal activity.

The reaction of 3,4-dihydrophenazin-1(2H)-one oxime with acetylene in the superbasic system KOH–DMSO afforded 1-aminophenazine in 32% yield instead of the expected pyrrolophenazine. The same product was also obtained under analogous conditions in the absence of acetylene.