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Vol 60, No 11 (2024)
Articles
Mass Spectra of New Heterocycles: XXVII. Investigation of Polysubstituted 4,4'-Dipyrromethanes by Electron Ionization
Abstract
Behavior of a wide range of previously unknown polysubstituted 4,4'-dipyrromethanes, namely 1,1'-bis{1-[2-(vinyloxy)ethyl]-2-amino-5-sulfanyl-1H-pyrrole-4-yl}ethanes, synthesized in one preparative stage from propargylamines, 2-(vinyloxy)ethyl isothiocyanate, and alkylating agents, under the action of electron ionization (70 eV) was studied for the first time. The studied compounds form a stable molecular ion {with the exception of 5.5'-di[(allyl-, propargyl-, and cyanomethyl)sulfanyl]dipyrromethanes}, the primary fragmentation of which proceeds in three directions with the formation of four key cations. Two of them (ions [M − R1]+ and [M − SR1]+) are associated with the breaking of C−S bonds in the sulfanyl substituent and between the latter and the pyrrole cycle. The third direction is due to the cleavage of the C−C bond between the pyrrole cycle and the methylene bridge linking the pyrrole cycles. In this case, two cations are formed, the peak intensity of which in the mass spectra ranges from 3 to 100% (depending on the structure of the substituents). The peaks of cation radicals [(M − R1) − SR1]+• have the highest intensity (up to 100%). The resulting fragmentation ions are stabilized as a result of cyclization with the participation of a vinyloxyethyl substituent.
1091-1100
Investigation of the Mechanism of the Alkylation Reaction of 2-Methylimidazole 1,1,3,3-Tetraiodpropane-2-on by the MALDI Method
Abstract
The mechanism of the alkylation reaction of 2-methylimidazole with 1,1,3,3-tetraiodopropan-2-one in the absence and presence an acceptor (CaCO3) of hydrogen iodide using laser desorption/ionization was studied for the first time. The composition of the reaction mixtures and possible routes for the formation of functionalized 2-methylimidazole derivatives were determined. N1 and N1,3-alkylation of 2-methylimidazole with reduced (1-iodopropan-2-one, 1,3-diiodopropan-2-one) or dehydroiodinated (2,3-diiodo-2-cyclopropen-1) forms 1,1, 3,3-tetraiodoproapan-2-one is a crucial step in the synthesis. The thermodynamic and kinetic characteristics of the reduction and dehydroiodination of 1,1,3,3-tetraiodoacetone were evaluated by quantum-chemical calculations using the [B3LYP/6-311+G(d,p)+dgdzvp) basis set.
1101-1111
Synthesis and antioxidant activity of n-substituted diamides based on 2-allyl-2-arylpent-4-en-1-amides of oxalic acid monoethyl ether
Abstract
By the reaction of 2-allyl-2-arylpent-4-en-1-amines with diethyl oxalate, amides of oxalic acid monoethyl ester were synthesized, which were converted into the corresponding diamides by interaction with non-aromatic amines. To synthesize aryl-substituted diamides, the same amines are reacted with anilides of oxalic acid monoethyl ester. The antioxidant activity of the synthesized diamides was studied.
1112-1119
Synthesis of Functionalized Spiro[1-benzofuran-2,5'-pyrimidine] Derivatives on the Base of 5-Arylidenebarbituric Acids
Abstract
Adducts of dimedone and 5-arylidenebarbituric acids react with N-bromosuccinimide in aqueous ethanol to give functionalized spiro[1-benzofuran-2,5'-pyrimidine] derivatives with moderate yields. The interaction of 5-benzylidenebarbituric acid with ethyl acetoacetate in the presence of N-bromosuccinimide leads to spiro[pyrimidine-5,6'-furo[2,3-d]pyrimidine] derivative.
1120-1124
1125-1136
Synthesis of carbomethoxymethylidene cyclopentenedione derivatives based on oxidative cleavage reactions of the allylic double bond 2-allyl-2,4-dichloro-5-(2,4,6-trimethoxyphenyl)-cyclopent-4-en-1,3-dione
Abstract
The reactions of oxidative cleavage of the allyl double bond of 2-allyl-2,4-dichloro-5-(2,4,6-trimethoxyphenyl)-cyclopent-4-ene-1,3-dione in the systems OsO4–NaIO4 and KMnO4–Et3BnN+Cl- were studied. It was shown that the intermediate aldehyde formed at the stage of periodate cleavage of the indicated 2-allylcyclopentene-1,3-dione was oxidized by the Jones reagent and, with subsequent elimination of HCl, was converted into the target 2-carbomethoxymethylidenecyclopent-4-ene-1,3-dione. In an alternative approach, permanganate oxidation of the basic 2-allylcyclopentene-1,3-dione leads to the corresponding diol in moderate yield.
1137-1141
Ruthenium-Catalyzed C(3)-H Alkylation of the Furan (Thiophene) Ring of 2-Furoyl- and Thiophene-2-carbonyl-1-methylimidazoles with Acrylic Acid Derivatives
Abstract
A method for the synthesis of 3-alkyl-2-furoyl- and thiophene-2-carbonyl-1-methylimidazoles by ruthenium-catalyzed selective C(3)-H alkylation of the furan (thiophene) ring 2-furoyl(thiophene-2-carbonyl)-1-methylimidazoles with esters, amides or nitrile of acrylic acid has been developed. The resulting compounds may be of interest as polyfunctional reagents or for the preparation of 3-(2-carboxyethyl)furan(thiophene)2-carboxylic acid derivatives.
1142-1149
Reaction of 4-Aroyl-1-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-5-metoxycarbonyl-1H-pyrrol-2,3-diones with 4-Aminoazobenzene
Abstract
Reaction of 4-aroyl-1-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-5-methoxycarbonyl-1H-pyrrole-2,3-diones with p-aminoazobenzene leads to the formation of methyl-3-aroyl-1-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-4-hydroxy-5-oxo-2-(4-(phenyldiazenyl)benzyl)-2,5-dihydro-1H-pyrrole-2-carboxylates.
1150-1153
1154-1158
Synthesis and Evaluation of the Neurotropic Activity of New Tetrahydropyridazin-3-one Derivatives
Abstract
It was established that 4-aryl-4-oxo-2-indol-3-yl butanoic acid and its derivatives upon interaction with hydrazine form 6-aryl-4-[(unsubstituted and substituted) indol-3-yl]-2, 3, 4, 5-tetrahydropyridazin-3-ones, while similarly constructed 4-aryl-4-oxo-2-heterylbutanoic acids under similar conditions are heterocyclized with subsequent azole elimination, resulting in the formation of 6-aryl-2,3-dihydropyridazin-3-ones. The study of the neurotropic activity of new tetrahydropyridazinones derivatives showed that all of the studied substances have anxiolytic action.
1159-1164