


Vol 53, No 4 (2017)
- Year: 2017
- Articles: 29
- URL: https://journal-vniispk.ru/1070-4280/issue/view/13445
Review
Trifluoromethanesulfonic acid in organic synthesis
Abstract
The review analyzes data published in the past decade on the use of trifluoromethanesulfonic acid (triflic acid, CF3SO3H, TfOH) in organic synthesis, in particular in electrophilic aromatic substitution (Friedel–Crafts) reactions, formation of carbon–carbon and carbon–heteroatom bonds, isomerizations, syntheses of carboand heterocyclic structures, and other reactions, as well as in natural and organometallic compounds chemistry. The high protonating power and low nucleophilicity makes trifluoromethanesulfonic acid capable of generating from organic molecules cationic species which can be detected by spectral methods (NMR, IR spectroscopy, etc.), and their transformations can be studied. Experimental simplicity and efficiency of reactions promoted by trifluoromethanesulfonic acid make it a convenient reagent for the synthesis of new organic compounds.



Reactivity of co-micellar systems based on dimeric functionalized tetraalkylammonium surfactant in phosphoryl and sulfonyl group transfer processes
Abstract
The reactivity of co-micellar systems based on dimeric functionalized tetraalkylammonium surfactant in phosphoryl and sulfonyl group transfer processes is lower than the reactivity of systems based on analogous imidazolium surfactant. The observed difference in the kinetics of acyl group transfer promoted by dimeric surfactants differing by the nature of the cationic center is likely to be general, and it results from both different nucleophilicities of their oximate fragments and different modes of solubilization of hydrophobic substrates. The most probable reasons for the latter are differences in intramolecular Coulomb interactions and packing of surfactant molecules in co-micelles.



Synthesis of symmetrical disulfides by reaction of fluorine-containing thiiranes with cyclic amines
Abstract
Regioselective opening of the thiirane ring in fluorine-containing thioglycidyl ethers and [(perfluorobutyl) methyl]thiirane by the action of cyclic amines afforded 1,2-aminothiols which were oxidized in situ to symmetrical disulfides. The rate of formation of the latter depended on the amine basicity. According to the NMR data, the resulting disulfides were mixtures of erythro and threo diastereoisomers.



Synthesis of thiols from isobornylphenols
Abstract
4-(3-Sulfanylpropyl)-2-isobornyl-6-methylphenol and 4-(sulfanylmethyl)-2,6-diisobornylphenol were synthesized from the corresponding 4-(bromoalkyl)phenols according to known procedures. Isobornylphenol with a trimethylene linker was converted into thiol by alkaline hydrolysis of thiouronium salt. The methylene-bridged analog was obtained by reduction of S-benzyl thioacetate with LiAlH4.



Reaction of N-sulfonyl-1,4-benzoquinone imines with enamines
Abstract
N-Sulfonyl derivatives of 1,4-benzoquinone imine reacted with enamines to give 1,4-addition products and products of their subsequent cyclization, substituted 5-aminobenzofurans and 5-aminoindoles, depending on the solvent nature, electron-withdrawing power of the substituent on the quinone imine nitrogen atom, and enamine structure. The presence of strong electron-withdrawing trifluoromethanesulfonyl group on the quinone imine nitrogen atom favors formation of 1,4-addition products and benzofuran derivatives.



Sodium difluoromethanesulfinate—A difluoromethylating agent toward protonated heterocyclic bases
Abstract
Free radical difluoromethylation of protonated heteroaromatic bases was accomplished using sodium difluoromethanesulfinate in combination with tert-butyl hydroperoxide in a two-phase system (methylene chloride–water) at room temperature. The difluoromethylation products of methyl pyridine-4-carboxylate, pyridine-4-carbonitrile, and 2-amino-1,3,4-thiadiazole were isolated on a preparative scale.



Fusion of 2-(furan-2-yl)thiazole to 1-methyl-1H-benzimidazole
Abstract
Methylation of 5(6)-nitro-1H-benzimidazole with methyl iodide in the presence of potassium hydroxide and N-methylpyrrolidin-2-one gave a mixture of isomeric 1-methyl-5-nitro- and 1-methyl-6-nitro-1H-benzimidazoles which were reduced with tin in concentrated aqueous HCl on heating. The resulting amines reacted with furan-2-carbonyl chloride in N-methylpyrrolidin-2-one to give furan-2-carboxamides which were treated with excess P2S5 in pyridine. Oxidation of isomeric furan-2-carbothioamides with K3[Fe(CN)6] in alkaline medium afforded a mixture of intramolecular cyclization products, 2-(furan-2-yl)-6-methyl-6H-imidazo[4,5-g][1,3]benzothiazole and 2-(furan-2-yl)-8-methyl-8H-imidazo[4,5-g][1,3]benzothiazole which were separated by column chromatography and identified.



Microwave synthesis of new azolyl-substituted thiazolo[5,4-d]thiazoles
Abstract
One-pot condensation of dithiooxamide with 4,5-dichloro-1,2-thiazole-3-carbaldehyde and 5-phenyl-1,2-oxazole-3-carbaldehyde, followed by oxidation of intermediate 2,5-dihydro[1,3]thiazolo[5,4-d]-[1,3]thiazoles with selenium dioxide, afforded previously unknown 2,5-bis(4,5-dichloro-1,2-thiazol-3-yl)- and 2,5-bis(5-phenyl-1,2-oxazol-3-yl)[1,3]thiazolo[5,4-d][1,3]thiazoles as first representative of bis-isothiazolyl- and bis-isoxazolyl thiazolothiazoles.



Reaction of 8-chloro-5,7-dinitroquinoline with β-dicarbonyl compounds
Abstract
3-(5,7-Dinitroquinolin-8-yl)pentane-2,4-dione, 5-(5,7-dinitroquinolin-8-yl)pyrimidine-2,4,6-trione, and 5-(5,7-dinitroquinolin-8-yl)-2,2-dimethyl-1,3-dioxane-4,6-dione cesium salts have been synthesized by a simple and efficient procedure via C-arylation of the corresponding β-dicarbonyl compounds with 8-chloro-5,7-dinitroquinoline.



Regioselective synthesis of benzo[g]- and benzo[f]quinolines by reaction of chalcones with naphthalen-2-amine
Abstract
Reactions of 4- and 4′-substituted chalcones with naphthalen-2-amine afforded isomeric benzo[g]- and benzo[f]quinoline derivatives. Depending on the substituent in the initial chalcone, the cyclization follows two pathways through different intermediates. The product structure was confirmed by IR, 1H and 13C NMR, and mass spectra and X-ray analysis.



New efficient synthesis of 6-aminopyrano[3,4-c]pyridines via Smiles type rearrangement
Abstract
A new efficient procedure has been developed for the synthesis of 6-aminopyrano[3,4-c]pyridines via Smiles type rearrangement. The procedure is characterized by improved overall yield and avoidance of experimentally difficult chlorination step.



4-alkylated 2-(2,3,5-tri-O-acyl-β-D-ribofuranosyl)- and 2-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl)-1,2,4-triazine-3,5-diones
Abstract
The alkylation of 2-(2,3,5-tri-O-acyl-β-D-ribofuranosyl)- and 2-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl)- 1,2,4-triazine-3,5-diones with benzyl halides afforded the corresponding 4-benzyl derivatives whose structure was determined by spectral methods, including X-ray analysis. Some of the synthesized compounds were tested for antibacterial and antitumor activity.



Reduction and diazotization of ethyl 7-amino-3-tert-butyl-4-oxo-4,6-dihydropyrazolo[5,1-c][1,2,4]triazine-8-carboxylate
Abstract
The ester group in ethyl 7-amino-3-tert-butyl-4-oxo-4,6-dihydropyrazolo[5,1-c][1,2,4]triazine-8-carboxylate was converted for the first time to methyl by the action of lithium tetrahydridoborate in the presence of boron trifluoride–diethyl ether complex. This reaction has almost no analogies among other classes of organic compounds. New difficultly accessible 7-chloro and 7-azido derivatives were synthesized via diazotization of the reduction product, and treatment of the latter with acetic anhydride afforded the exhaustively acetylated derivative. Diazotization of ethyl 7-amino-3-tert-butyl-4-oxo-4,6-dihydropyrazolo-[5,1-c][1,2,4]triazine-8-carboxylate, followed by reaction with sodium azide, gave the corresponding azide, and the product of azo coupling with ethyl acetoacetate failed to undergo intramolecular cyclization to tricyclic pyrazolo[3,2-c: 5,1-c′]bis[1,2,4]triazine system.



Cyclocondensations of 3-alkylpyrazol-5-amines with 3-arylprop-2-enals and cyclic 1,3-diketones
Abstract
Domino reactions of 3-alkylpyrazol-5-amines with 3-arylprop-2-enals and cyclic 1,3-diketones regioselectively afforded pyrazolo[3,4-b]pyridine derivatives. The alkylation and acylation of the synthesized compounds were studied using 3,7,7-trimethyl-4-[(E)-2-phenylethenyl]-2,4,6,7,8,9-hexahydro-5H-pyrazolo-[3,4-b]quinolin-5-one as model.



Synthesis of new 1-(3,4-dimethylphenyl)-1,5-dihydropyrazolo[3,4-d]pyrimidin-4-one derivatives
Abstract
New substituted pyrazolo[3,4-d]pyrimidin-4-ones have been synthesized as a result of a series of transformations including hydrolysis of ethyl 5-amino-1H-pyrazole-4-carboxylates, cyclization of the carboxylic acids thus obtained to pyrazolo[3,4-d][1,3]oxazin-4(1H)-ones, and treatment of the latter with substituted anilines. The final pyrazolo[3,4-d]pyrimidin-4-one derivatives can also be synthesized from 5-(arylamido)-1H-pyrazole-4-carboxylic acids in the presence of a catalytic amount of anhydrous zinc(II) chloride.



Reaction of trifluoroacetylchromenes with 6-aminouracils. Synthesis of pyrido[2,3-d]pyrimidines
Abstract
The condensation of trifluoroacetyl-substituted 4H-chromenes and 1H-benzo[f]chromenes with 6-amino-1,3-dimethyluracil and 6-aminothiouracil afforded a number of pyrido[2,3-d]pyrimidine derivatives containing a 2-hydroxybenzyl or 2-hydroxynaphthalen-1-ylmethyl group in the 6-position as a result of cascade transformation initiated by Michael addition.



Cycloaminomethylation of dihydric phenols catalyzed by d- and f-metal compounds
Abstract
An efficient method has been developed for the synthesis of 7,16,25-triaryl-7,8,16,17,25,26-hexahydro-6H,15H,24H-tribenzo[f,m,t][1,5,8,12,15,19,3,10,17]hexaoxatriazacyclohenicosines, 3,8-diaryl-2,3,4,7,8,9-hexahydrobenzo[1,2-e:4,3-e′]bis[1,3]oxazines, 3,9-bis(chlorophenyl)-3,4,9,10-tetrahydro-2H,8H-benzo[1,2-e:3,4-e′]bis[1,3]oxazines, and 2,9-bis(chlorophenyl)-1,2,3,8,9,10-hexahydrobenzo[1,2-e:6,5-e′]bis-[1,3]oxazines via cycloaminomethylation of pyrocatechol, resorcinol, and hydroquinone with N,N-bis(methoxymethyl) anilines in the presence of samarium catalysts.






Short Communications
Synthesis of ethyl (2E,4E)- and (2E,4Z)-5-chloropenta-2,4-dienoates
Abstract
An efficient synthetic approach to 2E,4E and 2E,4Z isomers of ethyl 5-chloropenta-2,4-dienoate has been developed on the basis of one-pot oxidation–olefination of readily accessible (E)- and (Z)-3-chloroprop-2-en-1-ols by the action of barium manganate and ethyl (triphenyl-λ5-phosphanylidene)acetate.



Product of the reaction of methyl (Z)-3-bromo-3-(4-methylbenzenesulfonyl) prop-2-enoate with acetylacetone
Abstract
Methyl (Z)-3-bromo-3-(4-methylbenzenesulfonyl)prop-2-enoate reacted with acetylacetone in THF in the presence of sodium hydride (3 h, 50°C) to give methyl (E)-3-acetyl-2-[(4-methylbenzenesulfonyl)-methylidene]-4-oxopentanoate as the only product. According to the X-ray diffraction data, the crystalline product has enol structure.



Reaction of methyl 2-methylidene-3-oxolup-20(29)-en-28-oate with triphenylphosphonium trifluoromethanesulfonate
Abstract
Phosphorylation of methyl 2-methylidene-3-oxolup-20(29)-en-28-oate with triphenylphosphonium trifluoromethanesulfonate in methylene chloride at 20°C afforded 90% of a γ-oxoalkylphosphonium salt containing a terpenoid fragment, [28-methoxy-3,28-dioxolup-20(29)-en-2-ylmethyl]triphenylphosphonium trifluoromethanesulfonate, as a mixture of two epimers (2S/2R) at a ratio of 2: 1.






New ω-chloroalkyl-substituted isatins and isoindigo
Abstract
New 1-(ω-chloroalkyl)isatins were synthesized by alkylation of isatin with α-bromo-ω-chloroalkanes. The reaction of 1-(3-chloropropyl)isatin with tris(diethylamino)phosphine followed the deoxygenation path with selective formation of isoindigo derivative.



S- and N-alkylation of 2,2′-(alkane-α,ω-diyldisulfanediyl)-bis(1,3-benzothiazoles) with 1-iodopropan-2-one in the presence of iodine
Abstract
The alkylation of 2,2′-(methylenedisulfanediyl)- and 2,2′-(ethane-1,2-diyldisulfanediyl)bis-(1,3-benzothiazoles) with 1-iodopropan-2-one involves exclusively the exocyclic sulfur atoms. The presence of an electron-withdrawing carbonyl group between the bridging methylene units in 1,3-bis(1,3-benzothiazol-2-ylsulfanyl)propane-2-one forces the alkylation to occur at the endocyclic nitrogen atoms.






Cascade cyclization of methyl 2-(azidomethyl)furan-3-carboxylates with 2-cyanoacetamides. Efficient synthesis of a new heterocyclic system, furo[3,2-e][1,2,3]triazolo- [1,5-a][1,3]diazepine
Abstract
Cascade cyclization of methyl 2-(azidomethyl)furan-3-carboxylate with 2-cyanoacetamides in the presence of 2 equiv of potassium tert-butoxide afforded a series of N-substituted 5-oxo-5,9-dihydro-4H-furo-[3,2-e][1,2,3]triazolo[1,5-a][1,3]diazepine-3-carboxamides.



Photochromism of 3H-2,1,4-benzoxadiazine 4-oxides with heterocyclic substituents on the benzene ring
Abstract
2H-Benzimidazole 1,3-dioxides undergo thermal isomerization to 3H-2,1,4-benzoxadiazine 4-oxides which are converted to 2H-benzimidazole 1-oxides on further heating. Irradiation of 3H-2,1,4-benzoxadiazine 4-oxides with sunlight induces their transformation to 2H-benzimidazole 1,3-dioxides. 3H-2,1,4-Benzoxadiazine 4-oxides containing nucleophilic heterocyclic substituents are considerably more stable to sunlight, and they can be used as photochromic compounds.



One-pot synthesis of isomeric 2-hydroxyphenyl-substituted cycloalkatetrazolopyrimidines
Abstract
Three-component condensation of salicylaldehyde with tetrazol-5-amine and cycloheptanone (cyclooctanone) gave isomeric 2-hydroxyphenyl-substituted cycloalka[d]- and cycloalka[e]tetrazolo[1,5-a]-pyrimidines whose ratios depended on the alicycle size.



Erratum
Erratum to: “Stereoselective addition of tellurium tetrachloride to 4-octyne”


