Cyclocondensation of n-(prop-2-yn-1-yl)- and n-(penta-2,4-diyn-1-yl)- <Emphasis Type="Italic">o</Emphasis>-phenylenediamines with phenyl isothiocyanate and carbon disulfide

The cyclocondensation of N-(prop-2-yn-1-yl)-o-phenylenediamines with phenyl isothiocyanate leads to the formation of 1-(prop-2-yn-1-yl)-1,3-dihydro-2H-benzimidazole-2-thiones irrespective of the substituent nature at the triple bond. Reactions of both mono- and diacetylenic derivatives of o-phenylenediamine with carbon disulfide in the presence of KOH proceed with the formation of two heterocyclic nuclei simultaneously. From N-(prop-2-yn-1-yl)-o-phenylenediamines containing an aryl substituent at the triple bond, and N-(penta-2,4-diyn-1-yl)-o-phenylenediamines 2-methylidene-2,3-dihydro[1,3]thiazolo[3,2-a]benzimidazoles are formed. The latter are readily isomerized under the action of base giving thiazolo[3,2-a]benzimidazoles. The cyclocondensation of N-(alk-2-yn-1-yl)-o-phenylenediamines with CS₂ leads to [1,3]thiazino[3,2-a]benzimidazoles.     

Terminal bis-acetylenes derived from 1,2-bis(1<Emphasis Type="Italic">H</Emphasis>-tetrazol-5-yl)ethane

The N(1)—N(1), N(2)—N(2), and N(1)—N(2) regioisomers of 1,2-bis[(prop-2-yn-1-yl)-1H-tetrazol-5-yl]ethane were first synthesized by alkylation of 1,2-bis(1H-tetrazol-5-yl)ethane with propargyl bromide. The peculiarities of the crystal structure of 1,2-bis[1-(prop-2-yn-1-yl)-1H-tetrazol-5-yl]ethane were evaluated by X-ray diffraction analysis. This compound is readily underwent Cu-catalyzed [3+2] cycloaddition with p-tolyl azide, p-nitrophenyl azide, and benzyl azide to give heterocyclic assembles bearing 1,2,3-triazole and tetrazole cycles. Catalyst-free [3+2] cycloadditions of 1,2-bis[1-(prop-2-yn-1-yl)-1H-tetrazol-5-yl]ethane and the mixtures of the N(1)—N(1), N(2)—N(2), N(1)—N(2) regioisomers with poly(glycidyl azide) oligomers resulted in 1,2,3-triazole cycles and crosslinking of the polymer chains.     

The First Analog of Pyrimidine Nucleosides with Two Nucleobases and Two d-Ribofuranose Residues

Russian Journal of Organic Chemistry - The reaction of 1,5-bis[1-(prop-2-yn-1-yl)uracil-3-yl]pentane with 2',3',5'-tri-O-acetyl-β-d-ribofuranosylazide followed by removing of...     

Base-Catalyzed Intramolecular Cycloaddition of Dialkyl(4-hydroxybut-2-yn-1-yl)[3-(4-bromophenyl)prop-2-yn-1-yl]ammonuim Chlorides and Recyclization of the Products

Russian Journal of Organic Chemistry - Dialkyl(4-hydroxybut-2-yn-1-yl)[3-(4-bromophenyl)prop-2-yn-1-yl]ammonium chlorides in the presence of 2 equiv of potassium hydroxide at room temperature...     

Cyclization of trifluoro-<Emphasis Type="Italic">N</Emphasis>-(prop-2-yn-1-yl)methanesulfonamides to <Emphasis Type="Italic">N</Emphasis>-(hydroxymethyl)-1,2,3-triazoles

Three-component heterocyclizations of trifluoro-N-(prop-2-yn-1-yl)methanesulfonamide, trifluoro-N-pheny-N-(prop-2-yn-1-yl)methanesulfonamide, and trifluoro-N,N-di(prop-2-yn-1-yl)methanesulfonamide with formaldehyde and sodium azide afforded N-{[2-(hydroxymethyl)-2H-1,2,3-triazol-4-yl]methyl}-, N-{[2-(hydroxymethyl)-2H-1,2,3-triazol-4-yl]methyl}-N-phenyl-, and N,N-bis{[2-(hydroxymethyl)-2H-1,2,3-triazol-4-yl]methyl}trifluoromethanesulfonamides as the major products together with minor 1-(hydroxymethyl)-1H-1,2,3-triazole isomers.     

Synthesis and in-vitro antioxidant activities of some coumarin derivatives containing 1,2,3-triazole ring

A new green protocol was developed for the S-alkylation of 2-mercapto-1,3,4-oxadiazole by the reaction of 5-substituted-2-mercapto-1,3,4-oxadiazole with propargyl bromide in sodium bicarbonate in water. The newly synthesized 5-[(substitutedphenoxy)methyl]-2-[(prop-2-yn-1-yl)sulfanyl]-1,3,4-oxadiazole when reacted with azidomethyl coumarins underwent regioselective reaction yielding 4-(((4-((5-((substitutedphenoxy)methyl)-1,3,4-oxadiazol-2-yl)sulfanylmethyl)-1H-1,2,3-triazol-1-yl)methyl)-6-methyl)-2H-chromene-2-one or 1-((4-((5-((substitutedphenoxy)methyl)-1,3,4-oxadiazol-2-yl)sulfanylmethy)-1H-1,2,3-triazol-1-yl-)methyl)-3H-benzo[f]chromene-3-one. Structures of the newly synthesized compounds were confirmed by spectral and analytical data. The compounds were screened for their in-vitro antioxidant property.     

Intramolecular Cycloaddition of [3-(Naphthalen-1-yl)prop-2-yn-1-yl](3-phenylprop-2-en-1-yl)ammonium Bromides and Cleavage of Some of the Obtained Cyclic Salts in Aqueous Alkali

Russian Journal of Organic Chemistry - Intramolecular cycloaddition of [3-(naphthalen-1-yl)prop-2-yn-1-yl](3-phenylprop-2-en-1-yl)ammonium bromide under very mild conditions afforded potentially...     

Reactions of selenium dihalides with vinylbenzenes

Alkoxyselenation of vinylbenzenes with selenium dihalides was accomplished for the first time. The reaction with selenium dibromide was the most efficient. Selenium dibromide reacted with vinylbenzene and 1-chloro-4-(prop-1-en-2-yl)benzene in chloroform or methylene chloride in the presence of methanol or ethanol to give the corresponding Markovnikov adducts, bis(2-alkoxy-2-phenylethyl) selenides and bis[2-alkoxy-2-(4-chlorophenyl)propyl] selenides in 82–95% yield with high regioselectivity. Bis(2-halo-2-phenylethyl) selenides can be obtained at low temperature (–60°C).     

Synthesis,X-ray structure,and stevens rearrangement of 1,1-di(prop-2-yn-1-yl)-2,5-dihydro-1H-pyrrol-1-ium bromide

1,1-Di(prop-2-yn-1-yl)-2,5-dihydro-1H-Pyrrol-1-ium bromide was obtained with interaction of 3-pyrroline with propargyl bromide and its structure was studied by X-ray analysis. It has been shown that the Stevens rearrangement of obtaining salt leads to the formation of 1-(hexa-4,5-dien-1-yn-3-yl)-2,5-dihydro-1H-pyrrol.     

Synthesis and characterization of benzodioxinone mono-telechelics and their use in block copolymerization

Poly(methyl methacrylate) (PMMA) and poly(ethylene glycol) methyl ether (mPEG)-based monotelechelics were quantitatively prepared by copper (I)-catalyzed azide/alkyne cycloaddition (CuAAC) click reactions using azido-terminated polymers and alkyne functional benzodioxinones. The monotelechelic containing dimethyl moities (2,2-dimethyl-5-(prop-2-yn-1-yloxy)-4H-benzo[d][1,3]dioxin-4-one) was heat-sensitive, whereas the monotelechelic containing diphenyl moieties (2,2-diphenyl-5-(prop-2-yn-1-yloxy)-4H-benzo[d][1,3]dioxin-4-one) was UV light sensitive. Based on the FT-IR, ¹H-NMR, and GPC investigations, the CuAAC click reactions enable the quantitative syntheses of monotelechelics under mild conditions. Moreover, the photosensitive mPEG-based monotelechelic was further utilized for the block copolymer synthesis upon UV-light irradiation. The photoinduced acylation of mPEG monotelechelic consist of (2,2-diphenyl-5-(prop-2-yn-1-yloxy)-4H-benzo[d][1,3]dioxin-4-one) in the presence of hydroxy-terminated poly(epsilon caprolactone) enabled the successful block copolymer formation.     

Synthesis of 3-[5-(biphenyl-4-yl)pyrrol-2-yl]-1-phenylprop-2-yn-1-ones by palladium-free cross-coupling between pyrroles and haloalkynes on aluminum oxide

Cross-coupling of 2-(biphenyl-4-yl)pyrroles derived from 1-(biphenyl-4-yl)ethanone oximes and acetylene with 3-bromo-1-phenylprop-2-yn-1-one on aluminum oxide gave 3-[5-(biphe-nyl-4-yl)pyrrol-2-yl]-1-phenylprop-2-yn-1-ones in 35–46% yields.     

Synthesis of <Emphasis Type="Italic">para</Emphasis>-substituted 1,4,5,6,7,7-hexachlorobicyclo-[2.2.1]hepta-2,5-dien-2-ylmethyl benzoates

[4 + 2]-Cycloaddition of hexachlorocyclopentadiene to para-substituted prop-2-yn-1-yl benzoates gave the corresponding 1,4,5,6,7,7-hexachlorobicyclo[2.2.1]hepta-2,5-dien-2-ylmethyl benzoates. The structure of the adducts was confirmed by independent synthesis, esterification of para-substituted benzoic acids with 1,4,5,6,7,7-hexachlorobicyclo[2.2.1]hepta-2,5-dien-2-ylmethanol.     

Reactions of 1,1,4,4-tetramethylsemicarbazide with prop-2-ynyl bromide, allyl bromide, and 1,3-dibromoprop-1-yne

1,1,4,4-Tetramethylsemicarbazide readily undergoes alkylation with prop-2-ynyl bromide and allyl bromide at the tertiary nitrogen atom of the hydrazine fragment to give 1-(prop-2-yn-1-yl)-and 1-(prop-2-en-1-yl)-1,1-dimethyl-2-(dimethylaminocarbonyl)hydrazinium bromides, respectively. A new procedure was proposed for the synthesis of 6-bromomethylidene-2-dimethylamino-4,4-dimethyl-5,6-dihydro-4H-1,3,4-oxadiazin-4-ium bromide by reaction of 1,1,4,4-tetramethylsemicarbazide with 1,3-dibromoprop-1-yne in acetonitrile.     

Azolyl-substituted 1,2,3-triazoles

Huisgen reaction of (E)-1,5-diarylpent-2-en-4-yn-1-ones and (E)-1,5-diarylpent-1-en-4-yn-3-ones afforded 1-aryl-3-(5-aryl-1H-1,2,3-triazol-4-yl)prop-2-en-1-ones and 3-aryl-1-(5-aryl-1H-1,2,3-triazol-4-yl)-prop-2-en-1-ones, respectively. (E)-1-Aryl-3-(5-phenyl-1H-1,2,3-triazol-4-yl)prop-2-en-1-ones reacted with hydrazine hydrate and phenylhydrazine to give 72–93% of 4-(3-aryl-4,5-dihydro-1H-pyrazol-5-yl)-5-phenyl-1H-1,2,3-triazoles which underwent dehydrogenation on heating in boiling acetic acid with formation of the corresponding pyrazole derivatives. The molecular structures of (E)-3-phenyl-1-(5-phenyl-1H-1,2,3-triazol-4-yl)prop-2-en-1-one and 4-[3-(4-methylphenyl)-1-phenyl-4,5-dihydro-1H-pyrazol-5-yl]-5-phenyl-1H-1,2,3-triazole were studied by X-ray analysis. 4-(3-Aryl-4,5-dihydro-1H-pyrazol-5-yl)-5-phenyl-1H-1,2,3-triazoles showed toxicity against Daphnia magna.     

A New Natural Lactone from <em>Dimocarpus</em> <em>longan</em> Lour. Seeds

A new natural product named longanlactone was isolated from Dimocarpus longan Lour. seeds. Its structure was determined as 3-(2-acetyl-1H-pyrrol-1-yl)-5-(prop-2-yn-1-yl)dihydrofuran-2(3H)-one by spectroscopic methods and HRESIMS.     

Palladium-catalyzed concerted [4 + 1] cyclization of prop-2-yn-1-ones and isocyanides

A palladium-catalyzed [4+1] cycloaddition of prop-2-yn-1-ones with double isocyanides is developed herein.The transformation worked well to produce a series of 2-amino-4-cyanofurans with high efficiency and a broad reaction scope.Based on mechanism studies,it is believed that the palladiumcatalyzed [4+1] imidoylative cycloaddition of prop-2-yn-1-ones was concerted.Treated with a ryl amine and H_2 O,the [4+1] cycloaddition of prop-2-yn-1-ones with double isocyanides provided 2-amino-4-amidylpyrroles efficiently.     

Microwave assisted synthesis of novel methylenebis{2-[(1-benzyl/cyclohexyl-1H-1,2,3-triazol-4-yl)methoxy]chalcones} and their antibacterial activity

A series of novel methylenebis{2-[(1-benzyl/cyclohexyl-1H-1,2,3-triazol-4-yl)methoxy]chalcones} (IVa-IVn) have been synthesized by the Click reaction and Claisen-Schmidt condensation of 5,5′-methylenebis[2-(prop-2-yn-1-yloxy)benzaldehyde] under microwave irradiation with high yields. All products have been characterized by spectral data including FT-IR, ¹H, and ¹³C NMR, mass spectrometry, and tested for their antibacterial activity.     

Water mediated deprotective intramolecular hydroamination of N-propargylaminopyridines: synthesis of imidazo[1,2-a]pyridines

Metal-free synthesis of substituted imidazole [1,2-a]pyridines from deprotective N-(prop-2-yn-1-yl)pyridin-2-amines in water is elucidated. Electron releasing substituents on pyridine ring provided pure products in quantitative yields without separation by column chromatography.     

Synthesis and structure of 3-allenyl-4-aryl-7,7-dimethyl-5-oxo-2-thioxo-1,2,3,4,5,6,7,8-octahydroquinoline-3-carbonitriles

3-Allenyl-4-aryl-7,7-dimethyl-5-oxo-2-thioxo-1,2,3,4,5,6,7,8-octahydroquinoline-3-carbonitriles were synthesized via [3,3]-sigmatropic rearrangement of 4-aryl-7,7-dimethyl-5-oxo-2-(prop-2-yn-1-ylsulfanyl)-1,4,5,6,7,8-hexahydroquinoline-3-carbonitriles. The structure of 3-allenyl-7,7-dimethyl-4-(2-nitrophenyl)-5-oxo-2-thioxo-1,2,3,4,5,6,7,8-octahydroquinolin-3-carbonitrile was determined by X-ray analysis.     

Sonogashira reaction of 5-substituted 3-(prop-2-yn-1-yl)oxolan-2-ones

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.