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Article
Reaction of Aldonitrones with N-Phenyl-9,10-dihydro-9,10-ethenoanthracene-11,12-dicarboximide
Thermal addition of aldonitrones (C,N-diaryl- and N-aryl-C-arylcarbamoylnitrones) to the double bond of N-phenyl-9,10-dihydro-9,10-ethenoanthracene-11,12-dicarboximide yields heteropropellanes containing isoxazol...
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Article
A Quantum Chemical Study of the Acidity of Acetylene and 1,2-Dihydrobuckminsterfullerene Derivatives
DFT PBE0/cc-pVDZ method and the polarizable continuum model were used to determine pK a values for buckminsterfullerene-acetylene hybrids C60HCCH, C60HCN, tert-butylacetylene, a...
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Article
Synthesis of Isoxazolopyrrolo[2,1-a]isoquinoline, Isoxazolo[5′,4′: 1,2]indolizino[8,7-b]indole, and Isoxazolo-[5,4-a]thieno[2,3-g]indolizine Derivatives by Intramolecular Cyclization of Hydroxylactams Constituting a Fragment of the Pyrroloisoxazole System
6-Hydroxy-5-[2-(naphthalen-1-yl)ethyl]-3a,5,6,6a-tetrahydro-4H-pyrrolo[3,4-d]isoxazol-4-ones in the presence of boron trifluoride–diethyl ether complex underwent cyclization to benzo[f]isoxazolo[5′,4′: 3,4]- pyrr...
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Article
Regio- and stereoselective (3 + 2)-cycloaddition of nitrile oxides and nitrones to N-vinylindole
1,3-Dipolar cycloaddition of nitrile oxides and nitrones to N-vinylindole proceeds regioselectively at the exocyclic multiple bond to form 5-indolyl-substituted isoxazolines and isoxazolidines in good yields.
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Article
GC/MS characterization of monosubstituted hydrazones of glyoxylic acid ethyl ester
Electron ionization mass spectra and gas chromatographic retention indices of a series of newly synthesized N-monosubstituted (alkyl, aryl, allyl) hydrazones of glyoxylic acid ethyl ester RNHN=CHCO2C2H5 were cons...
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Article
Oxidation of reaction products of p-aryl-С,С-disubstituted nitrones and dimethyl 3-methylenecyclopropane-1,2-dicarboxylate
Oxidation with 2,3-dichloro-4,5-dicyanobenzoquinone of 2,4-dihydro-1Н-azeto[1,2-a]quinoline-3,4 -dicarboxylates obtained in the reaction of N-aryl-С,С-disubstituted nitrones with Feist’s acid ester resulted in th...
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Article
Reductive cleavage and subsequent transformations of 5-oxa-6-azaspiro[2.4]heptane-1-carboxylates
Treatment of methyl 4,6-diaryl-5-oxa-6-azaspiro[2.4]heptane-1-carboxylates with zinc in acetic acid leads to cleavage of the N–O bond in the isoxazolidine ring with formation of 1,3-amino alcohols whose subseq...
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Article
Regio- and diastereoselective cycloaddition of stable cyclic azomethine imines to N-arylitaconimides
1,3-Dipolar cycloaddition of stable N,N′- and C,N-cyclic azomethine imines based respectively on pyrazolidin-3-one and 3,4-dihydroisoquinoline to N-arylitaconimides proceeds strictly regioselectively resulting in...
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Article
Steric hindrances to the cycloaddition of (Z)-1-arylmethylidene-5,5-dimethyl-3-oxopyrazolidin-1-ium-2-ides to N-arylmaleimides
Sterically hindered cycloaddition of (Z)-1-arylmethylidene-5,5-dimethyl-3-oxopyrazolidin-1-ium-2-ides to 4-mono- and 2,6-disubstituted N-arylmaleimides requires prolonged heating (40–60 h) at ~150–155°C and yield...
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Article
Regio- and stereoselective cycloaddition of nitrones to 1-vinyl-4,5-dihydro-1H-benzo[g]indole
Nitrones cycloaddition to 1-vinyl-4,5-dihydro-1H-benzo[g]indole proceeds regio- and steroselectively affording a single diastereomer of 5-(hetaryl-substituted)isoxazolidine.
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Article
Regioselective cycloaddition of C,N-diarylnitrones to arylallenes and of N-aryl-C-carbamoylnitrones to methyl buta-2,3-dienoate
Cycloadditions of C,N-diarylnitrones to non-activated arylallenes and of N-aryl-C-carbamoylnitrones to methyl buta-2,3-dienoate regioselectively afforded mixtures of diastereoisomeric substituted 4-methylideneiso...
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Article
Quantum chemical study of ethynylfullerenes
DFT PBE0/cc-pVDZ method was applied to calculate the structural parameters of C60C(CCH)2, C60H2, C60H(t-Bu), C60HCCH, C60(CCH)2 molecules, and of the corresponding carbanions. The length of the carbon-carbon full...
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Article
Regioselective cycloaddition of C-carbamoylnitrones to methyl (E)-2-(2-phenylcyclopropylidene)acetate and methyl (E)-2-methylidene-3-phenylcyclopropane-1-carboxylate
N-Aryl-C-(arylcarbamoyl)nitrones regioselectively add to methyl 2-(2-phenylcyclopropylidene)-acetate and methyl 2-methylidene-3-phenylcyclopropanecarboxylate to give in each case two diastereoiso...
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Article
Methyl (E)-2-(2-phenylcyclopropylidene)acetate: Synthesis, isomerization, and reaction with 1,3-diphenyl-2-benzofuran
Treatment of 3-methyl-2-phenylcycloprop-2-ene-1-carboxylic acid with potassium tert-butoxide induced its isomerization into trans-2-methylidene-3-phenylcyclopropane-1-carboxylic acid which was converted into meth...
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Article
Stereoselective cycloaddition of diphenylisobenzofuran to N-arylitaconimides
A reaction of 1,3-diphenylisobenzofuran with N-arylitaconimides gives the [4+2] cycloaddition products with the 11′-oxaspiro[pyrrolidine-3,9′-tricyclo[6.2.1.0 2,7 ]undeca-2′,4′,6...
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Article
Stability of diazocarbonyl compounds under the conditions of gas chromatography and chromatography-mass spectrometry analysis
The gas chromatographic analysis of alkyldiazoacetates N2CHCO2R (R = CH3 − C4H9), α-aliphatic diazoketones RCOCHN2 (R = C3H7, C5H11, and C9H19), and aryl-substituted diazoketones Ph (CH2) n ...
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Article
(Z)-1-alkylidene- and 1-arylmethylidene-5,5-dimethyl-3-oxopyrazolidin-1-ium-2-ides and their cycloaddition to N-arylmaleimides
The reaction of (Z)-1-arylmethylidene-5,5-dimethyl-3-oxopyrazolidin-1-ium-2-ides with para-substituted N-arylmaleimides at 110°C is cis-stereoselective [cis/trans-adduct ratio ≥(9–10): 1]. Under analogous conditi...
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Article
Synthesis of dispiro[2.1.3.1]nonane and trispiro[2.1.1.37.15.13]-dodecane
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Article
Diastereoselective 1,3-dipolar cycloaddition of C,N-diaryl- and C-amido-N-arylnitrones to arylpropenones
C,N-diarylnitrones and C-amido-N-arylnitrones add diastereoselectively to the substituted arylpropenones to give the substituted isoxazolidine possessing 3RS,4SR,5SR configuration. Replacement of...
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Article
Regioselective addition of cyclic nitrones to Feist’s acid dimethyl ester
Cyclic nitrones, viz., tetrahydropyridine 1-oxide, 3,4-dihydroisoquinoline 2-oxide, and 2-methoxycarbonyl-4,5-dihydro-3H-pyrrole 1-oxide, regioselectively add to dimethyl 3-methylidenecyclopropane-1,2-dicarboxyla...
