α-Ureidoalkylation of 1,3-bis(hydroxymethyl)-imidazolidin-2-one

The α-ureidoalkylation of imidazolidine-2,4-dione, urea, carboxylic acid amides, and sulfonamides has been studied using 1,3-bis(hydroxymethyl)-imidazolidin-2-one as ureidoalkylating agent. Methods have been developed for the synthesis of 1,3-bis(2,4-dioxoimidazolidin-1-ylmethyl)-, 1,3-bis(acetylaminomethyl)-, 1,3-bis(benzoylaminomethyl)-, 1,3-bis(phenylsulfonylaminomethyl)-, and 1,3-bis(p-toluenesulfonylaminomethyl)imidazolidin-2-ones. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1655–1659, November, 2007.     

Intermolecular [2+2] photocycloaddition of chalcones with 2,3-dimethyl-1,3-butadiene under neat reaction conditions

The intermolecular [2 + 2] photocycloaddition of chalcones with 2,3-dimethyl-1,3-butadiene under visible-light irradiation for the synthesis of cyclobutane derivatives has been developed. Without using any photosensitizer, metallic catalyst and solvent, the reaction proceeded with high regioselectivity and moderate to high stereoselectivity. Mild reaction conditions and no additives make the reaction easy to operate. Control experiments and density functional theory (DFT) computations demonstrated that the reaction takes place via visible-light activation of chalcones, which is different from the previously reported [2 + 2] cycloaddition of chalcones.     

Synthesis of some new 3-[5-(2-oxo-2H-3-chromenyl)-1,3-oxazol-2-yl]-1,3-thiazolan-4-ones as antimicrobials

<正>A series of some new 2-imino-5-[(Z)-1-(4-methylphenyl)methylidene]-3-[5-(2-oxo-2H-3-chromenyl)-1,3-oxazol-2-yl]-1,3- thiazolan-4-ones 5a-j has been synthesized and assayed for their antibacterial activity against Gram-positive bacteria viz.Bacillus subtilis(ATCC 6633),Staphylococcus aureus(ATCC 6538p) and Micrococcus luteus(IFC 12708),and Gram-negative bacteria viz. Proteus vulgaris(ATCC 3851).Salmonella typhimurium(ATCC 14028) and Escherichia coli(ATCC 25922).Among the screened compounds,5d,5e,5f,5g,and 5j exhibited potent inhibitory activity compared to standard drug,and emerged as potential molecules for further development.     

Cationic polymerizations of substituted 2-methylene-1,3-dioxocyclic acetals, 2-methylene-1,3-dithiolane and copolymerization of 2-methylene-1,3-dithiolane with 4-(t-butyl)-2-methylene-1,3-dioxolane1

Carbon black-supported sulfuric acid or BF₃·Et₂O-initiated polymerizations of 2-methylene-4,4,5,5-tetramethyl-1,3-dioxolane (1), 2-methylene-4-phenyl-1,3-dioxolane (2), and 2-methylene-4-isopropyl-5,5-dimethyl-1,3-dioxane (3) were performed. 1,2-Vinyl addition homopolymers of 1–3 were produced using carbon black-supported H₂SO₄ initiation at temperatures from 0°C to 60°C whereas both ring-opened and 1,2-vinyl structural units were present in the polymers using BF₃·Et₂O as an initiator. Cationic polymerizations of 2-methylene-1,3-dithiolane (4) and copolymerization of 4 with 2-methylene-4-(t-butyl)-1,3-dioxolane (5) were initiated with either carbon black-sulfuric acid or BF₃·Et₂O. Insoluble 1,2-vinyl addition homopolymers of 4 were obtained upon initiation with the supported acid or BF₃·Et₂O. A soluble copolymer of 2-methylene-1,3-dithiolane (4) and 4-(t-butyl)-2-methylene-1,3-dioxolane (5) was obtained upon BF₃·Et₂O initiation. This copolymer is composed of three structural units: a ring-opened dithioester unit, a 1,2-vinyl-polymerized 1,3-dithiolane unit, and a 1,2-vinyl polymerized 4-(t-butyl)-1,3-dioxolane unit. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 2823–2840, 1999     

Acid-catalyzed aza-Diels-Alder versus 1,3-dipolar cycloadditions of methyl glyoxylate oxime with cyclopentadiene

The acid-catalyzed 1,4- and 1,3-cycloadditions between methyl glyoxylate oxime (1) and cyclopentadiene were investigated using various Lewis and/or Bronsted acids at different temperatures in dichloromethane as solvent. Besides the expected new adducts, (±)-methyl [(3-exo)-2-hydroxy-2-azabicyclo[2.2.1]hept-5-ene]-3-carboxylate (2) and (±)-methyl [(3-endo)-2-hydroxy-2-azabicyclo[2.2.1]hept-5-ene]-3-carboxylate (3), a third adduct, (±)-methyl (1R,4R,5R)-(2-oxa-3-azabicyclo[3.3.0]oct-7-ene)-4-carboxylate (4), whose formation can be explained by a 1,3-dipolar cycloaddition, was obtained. Yields and product ratios were found to be more dependent on the catalyst than on the temperature; these results and the stereochemistry of the adducts, confirmed by spectroscopic data (¹H and ¹³C NMR) and by X-ray crystallography, were used to analyze and propose a mechanistic explanation for both cycloadditions.     

Synthesis and structure of 1,3-dialkyl-4-(sulfonylimino)imidazolidin-2-ones

The reactions of 1,3-dialkyl-4,5-dihydroxyimidazolidin-2-ones with alkyl sulfamides have been studied and previously undescribed 1,3-dialkyl-4-(alkylaminosulfonylimino)imidazolidin-2-ones have been obtained. The structure of 1,3-dimethyl-4-(benzenesulfonylimino)imidazolidin-2-one was investigated by X-ray structural analysis. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1159–1166, August, 2007.     

Organocatalytic Enantioselective 1,3-Dipolar [6+4] Cycloadditions of Tropone

A highly stereoselective 1,3-dipolar [6+4] cycloaddition towards bridged azabicyclo[4.3.1]decane scaffolds has been developed, reacting aldehydes, 2-aminomalonates and tropone under mild conditions in the presence of a chiral phosphoric acid catalyst. The scope is demonstrated for a series of aldehydes and 2-aminomalonates, and the reaction proceeds in high yields, >95:5 d.r. and up to 99 % ee. A series of transformations, as well as a mechanistic proposal, are presented.     

An efficient and green method for the synthesis of [1,3]oxazine derivatives catalyzed by thiamine hydrochloride (VB1) in water

An efficient and convenient synthesis of 1,3-oxazine derivatives has been achieved by the one-pot, multicomponent condensation of α- or β-naphthol, an aniline and formaldehyde using thiamine hydrochloride (VB₁) as a versatile biodegradable and reusable catalyst in water as a universal solvent.     

Interaction of benzimidazole-2-thione with propargyl bromide and 1,3-dibromopropyne

Interaction of benzimidazole-2-thione with propargyl bromide under found conditions permitted the direct synthesis of 2-(2-propynylsulfanyl)-3H-1,3-benzimidazolium bromide, the base 2-(2-propynylsulfanyl)-1H-1,3-benzimidazole, stable crystalline 2-(1,2-propadienylsulfanyl)-1H-1,3-benzimidazole, and 3-methyl[1,3]thiazolo[3,2-a][1,3]benzimidazole. The reaction of benzimidazole-2-thione with 1,3-dibromopropyne in chloroform or absolute methanol gave 2-(3-bromo-2-propynylsulfanyl)-3H-1,3-benzimidazolium bromide, and in absolute methanole in the presence of a twofold excess of sodium methoxide the reaction proceeded stereo-and regioselectively to give 3-[(Z)-bromomethylidene][1,3]thiazolo[3,2-a][1,3]benzimidazole. Presented to Academician B. A. Trofimov on his 70^th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, 1399–1405, September, 2008.     

Rh2(oac)4-catalyzed reactions of methyl diazoacetate with 1,3-oxazolidines and 1,3-oxathiolanes

Methoxycarbonylcarbene generated by catalytic decomposition of methyl diazoacetate in the presence of Rh₂(OAc)₄, is regioselectively inserted into the C(2)-O bond of 3-alkyl-2-phenyl-1,3-oxazolidines and into the C(2)-S bond of 2-phenyl-1,3-oxathiolane. Study by the competitive reaction method demonstrated that the relative reactivity toward the insertion of the methoxycarbonylcarbene fragment into the C-heteroatom bond increases in the series of 1,3-dioxolane, 1,3-oxazolidine, and 1,3-oxathiolane. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1411–1415, August, 2006.     

Copper(I) and palladium nanoparticles supported on ethylenediamine‐functionalized cellulose as an efficient catalyst for the 1,3‐dipolar cycloaddition/direct arylation sequence

Cu(I) and nanoparticles of Pd supported on ethylenediamine‐functionalized cellulose as a novel bio‐supported catalyst was synthesized and characterized. The synthesized catalyst was found to be a highly efficient heterogeneous catalyst for the synthesis of 1,4,5‐trisubstituted 1,2,3‐triazoles through a sustainable 1,3‐dipolar cycloaddition/direct arylation sequence. The catalyst could be easily recovered by simple filtration and reused for at least five cycles without losing its activity. Copyright © 2014 John Wiley & Sons, Ltd.     

MgSiO3 nanoparticle‐catalyzed 1,3‐dipolar cycloaddition reactions in the synthesis of novel spiroindane‐1,3‐diones derived from substituted chalcones

Employment of metal nanoparticles has been one of the most promising synthetic strategies for a number of chemical transformations. New spiroindane‐1,3‐diones were synthesized through [3 + 2] cycloaddition in moderate to high yields by a three‐component reaction of heterocyclic chalcone derivatives, ninhydrin, and sarcosine/L‐proline. The presence of heterogenous MgSiO₃ nanoparticles (NPs) under microwave irradiation showed a robust effect in improving the yield of the desired products. Furthermore, the catalyst may be recovered and reused without significant loss of activity.     

Acetals and ethers,XVII. One- or two-step syntheses of 2-(2-alkoxyethyl)-1,3-dioxacyclanes

2-(2-Alkoxyethyl)-1,3-dioxanes (1) were prepared by ap-toluenesulfonic acid-catalyzed, one-step reaction of propenal with a mixture of aliphatic alcohol and trimethylene glycol in good yields. The transacetalization reaction of 1,1,3-trialkoxypropanes (3) with ethylene glycol or propylene-(1,2)glycol afforded good yields of pure 2-(2-alkoxyethyl)-1,3-dioxolanes (5 or6), respectively. This reaction proceeds through an intermediate 1,3-dialkoxy-1-(2-hydroxyalkoxy)-propane.

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Ein- oder Zweistufensynthese von 2-(2-Alkoxyethyl)-1,3-dioxacyclanen

Zusammenfassung In der durchp-Toluolsulfonsäure — katalysierten, direkten Reaktion von Propenal mit einem Gemisch von aliphatischem Alkohol und Trimethylenglykol wurden die entsprechenden 2-(2-Alkoxyethyl)-1,3-dioxane (1) in guten Ausbeuten erhalten. Die Umacetalisierung von 1,1,3-Trialkoxypropanen (3) mit Ethylenglykol oder 1,2-Propylenglykol lieferte 2-(2-Alkoxyethyl)-1,3-dioxolane (5 oder6) in guten Ausbeuten. Die Umacetalisierungsreaktion von 1,1,3-Trialkoxypropanen verläuft über 1,3-Dialkoxy-1-(2-hydroxyalkoxy)-propane als Zwischenprodukte.

     

1,3-Dipolar cycloaddition of phthalazinium ylides to 5-arylidene-2-spirocyclohexane-1,3-dioxane-4,6-diones

Tetrahydrospiropyrrolo[2,1-a]phthalazines were synthesized by the reaction of 5-arylidene-2-spirocyclohexane-1,3-dioxane-4,6-diones with phthalazinium ylides. One of the reaction products, viz., 3-ethoxycarbonyl-2-(4-methoxyphenyl)-2′,2′-pentamethylene-1,2,3,10b-tetrahydrospiro[pyrrolo[2,1-a]phthalazine-1,5′-[1,3]dioxane]-4′,6′-dione, was studied by X-ray diffraction. The spectroscopic characteristics of the reaction products are discussed. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2362–2365, October, 2005.     

Reactions of diazoalkanes with unsaturated compounds 16. Catalytic reactions of diazomethane with 2-alkenyl-1,3-oxazolidines and 2-alkenyl-1,3-oxathiolanes

The influence of 1,3-oxazolidine and 1,3-oxathiolane fragments in substituted alkenes on the direction of their catalytic reaction with diazomethane has been investigated. The olefins bearing an oxazolidine substituent in the α- or γ-position and an oxathiolane substituent in the γ-position relative to the C=C bond react with diazomethane in the presence of Pd(acac)₂ selectively resulting in cyclopropanation products. The use of Cu(OTf)₂ does not result in cyclopropanation; however Cu(OTf)₂ catalyzes the reaction of diazomethane with 2-(alk-1-enyl)-1,3-oxathiolanes yielding 2,3,5,6-tetrahydro-1,4-oxathiocines formed through the [2,3]-sigmatropic rearrangement of the intermediate sulfonium ylides. For Part 15 see Ref. 1. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 604–608, March, 2008.     

Coupling routes to hexafluoro-1,3-butadiene, substituted-1,3-fluorine-containing butadienes and fluorinated polyenes

Hexafluoro-1,3-butadiene was readily prepared via a variety of self-coupling processes, such as Cu(0) mediated self-coupling of iodotrifluoroethene, Pd(0) catalyzed coupling of iodotrifluoroethene with the trifluorovinylzinc reagent, and CuBr₂ mediated coupling of the trifluorovinylzinc reagent. Perfluoro-2,3-dimethyl-1,3-butadiene was readily synthesized by the reaction of pentafluoropropenyl-2-zinc reagent with either CuBr₂ or FeCl₃. Alternatively, perfluoro-2,3-dimethyl-1,3-butadiene was prepared by oxidation of the pentafluoropropenyl-2-copper reagent with dioxygen. Cu(0) mediated coupling of an (E)-substituted ,β-difluoro-β-iodostyrene provided the first useful route to a (Z)(Z)-1,4-diaryl-1,3-tetrafluorobutadiene. Extension of the Cu(0) mediated coupling methodology to a perfluorodienyl iodide demonstrated a useful stereospecific route to perfluoropolyenes.     

Iodine-alumina as an efficient and useful catalyst for the regeneration of carbonyl functionality from the corresponding 1,3-oxathiolanes and 1,3-dithiolanes in aqueous system

A simple and useful method has been demonstrated for the deprotection of 1,3-oxathiolanes and 1,3-dithiolanes to the corresponding carbonyl compounds in excellent yield by employing catalytic amount (30 mol %) of iodine supported on neutral alumina in ethanol-water or water. The major advantages of this protocol are mild reaction conditions, less reaction time, easy to handle, high yields, inexpensive reagent and environmentally benign.     

Stereoselective Synthesis of Functionalized 1,3-Enynes through Recyclable Copper(I)-Catalyzed Three-Component Reaction of Terminal Alkynes,Diazoesters and Aldehydes

A highly efficient heterogeneous copper(I)-catalyzed three-component coupling of terminal alkynes, diazoesters and aldehydes has been achieved by using 10 mol% of copper(I) iodide complex [N,N-CuI-MCM-41] anchored on 2-aminoethylamino-modified mesoporous material MCM-41 as the catalyst under mild conditions, delivering a wide variety of 2-alkoxycarbonyl-substituted (E)-1,3-enynes in mostly good to high yields with excellent stereoselectivity. The heterogenized copper(I) complex can be facilely prepared from inexpensive reagents by using a simple procedure and exhibits a remarkably higher catalytic activity than CuI, and can be recycled more than ten times without a significant drop in its catalytic efficiency. This protocol represents the first example of heterogeneous copper-catalyzed stereoselective construction of functionalized 1,3-enynes from simple and commercially available starting materials.     

Synthesis of functional polymers bearing cyclic carbonate groups from (2-oxo-1,3-dioxolan-4-yl) methyl vinyl ether

(2-Oxo-1,3-dioxolan-4-yl) methyl vinyl ether (OVE) was synthesized with high yield by addition reaction of glycidyl vinyl ether with carbon dioxide using tetrabutylammonium bromide (TBAB) as a catalyst. OVE was also prepared by reaction with β-butyrolactone or sodium hydrogencarbonate in the presence of TBAB as the catalyst. Poly [(2-oxo-1,3-dioxolan-4-yl) methyl vinyl ether] [P(OVE)] was obtained with high yield by cationic polymerization of OVE catalyzed using boron trifluoride diethyl ether complex in dichloromethane. Polymers bearing pendant 5-membered cyclic carbonate groups were also prepared by radical copolymerization of OVE with some electron-accepting monomers. Furthermore, addition reaction of P(OVE) with alkyl amines yielded the corresponding polymer having pendant 2-hydroxyethyl carbamate residue with high conversions. © 1994 John Wiley & Sons, Inc.     

Ni@zeolite-Y nanoporous; a valuable and efficient nanocatalyst for the synthesis of N-benzimidazole-1,3-thiazolidinones

In this project, Ni(II) ion stabilized on zeolite-Y (NNZ) was developed as a high efficient nanoporous catalyst for the synthesis of 3-benzimidazolyl-1,3–thiazolidin-4-one derivatives via condensation of 2-aminobenzimidazole, aromatic aldehydes and thioglycolic acid in ethanol under ambient conditions. Compared with conventional protocols, this methodology has promising features such as the use of inexpensive, stable, recyclable and safe catalyst, shorter reaction times and higher yields, nontoxic solvent and easy isolation of the products.