Synthesis and ‘click’ cycloaddition reactions of tetramethoxy- and tetrapropoxy-2-(ω-azidoalkyl)calix[4]arenes

2-(ω-Chloroalkyl)tetramethoxycalix[4]arenes are converted to 2-(ω-azidoalkyl)tetramethoxy- and cone-2-(ω-azidoalkyl)tetrapropoxycalix[4]arenes, the former by substitution and the latter by demethylation to 2-(ω-chloroalkyl)tetrahydroxycalix[4]arenes, which are O-propylated before substitution of azide for chloride. The azide-terminated calixarenes undergo Cu(I)-catalyzed 1,3-cycloaddition to terminal alkynes to give 1,4-disubstituted 1,2,3-triazoles, demonstrating the potential to couple calixarenes from a tether at the 2-position (methylene bridge) to substrates that bear a terminal alkyne group. The cone conformation of cone-2-(4-chlorobutyl)tetrapropoxycalix[4]arene has been confirmed by X-ray diffraction.     

Stereoselective synthesis of 3-(ω-hydroxyalkyl)-2-pyrrolidinones from α-alkylidenelactones and nitromethane

Enantiopure 3-(ω-hydroxyalkyl)-2-pyrrolidinones 7 and 9 were synthesised by Michael-addition of nitromethane to chiral α-alkylidenelactones 1 followed by reduction of the resulting 3-(β-nitroalkyl)-lactones and ring transformation of the intermediate 3-(β-aminoalkyl)-lactones. In an analogous manner the naturally occurring costuslactone 10 was transformed into the butyrolactam 12.     

Synthesis of indanones by sequential Heck-reduction–cyclization–alkylation (HRCA) reactions

A simple and efficient synthesis of indanones, bearing a quaternary carbon centre, has been developed. The method features, in a one-pot process, the use of a multi-task palladium catalyst for the sequential Heck-reduction reactions, followed by a base-mediated cyclization–alkylation sequence. This methodology, called Heck-reduction–cyclization–alkylation (HRCA), is carried out under mild and simple experimental conditions with the use of inexpensive reagents. The mild conditions have been made possible by the use of diazonium salts that allow Heck couplings at moderate temperature (40 °C) under ligand-free conditions.     

Synthesis and cycloaddition reactions of α-substituted acrolein dimethylhydrazones containing an acetal group

A series of new -substituted acrolein dimethylhydrazones containing an acetal group were synthesized. These hydrazones react with acrylonitrile or methyl acrylate according to the Diels—Alder reaction pattern to give substituted tetrahydropyridines. An unusual [2+4]- and [2+3]-cycloaddition cascade reaction involving -diethoxymethylacrolein dimethylhydrazone was discovered.     

Synthesis of heterocycle appended spiro(oxindole-3,2’-pyrrolidine) derivatives from heterocyclic ylidenes and azomethine ylide through 1,3-dipolar cycloaddition reactions

Spiro(oxindole-3,2’-pyrrolidine) is a privileged scaffold displaying a wide spectrum of biological activities. A series of these molecules containing heterocyclic rings attached to the pyrrolidine unit has been synthesized utilizing the classical 1,3-dipolar cycloaddition reaction of azomethine ylide with heterocyclic ylidenes. The method portrays a two-step functionalization of thiophene/furan with spiropyrrolidine oxindoles in the second/third positions. Biological activity evaluation for antibacterial, cell toxicity, and anticancer potential were done. Compounds exhibited no antibacterial activity. However, they were found to be non-cytotoxic upto 100?µg/ml and to exhibit potent anticancer activity by activating pro-apoptotic genes p53 and caspase 7.     

Synthesis,structure and reactions of μ-oxobis(arenesulfonatotriarylbismuth)

Hydrolysis of triarylbismuth bis(arenesulfonates) in acetone gives bismuth derivatives of the general formula [Ar₃Bi(OSO₂Ar)]₂O (Ar = Ph, p-Tol; Ar = Ph, C₆H₄Me-4, C₆H₃Me₂-2,4, C₆H₃Me₂-3,4). The structure of -oxobis[(3,4-dimethylbenzenesulfonato)triphenylbismuth] was established by means of X-ray diffraction. The molecule has a linear centrosymmetric structure with the bridging oxygen atom in the inversion center. The bismuth atom has a distorted trigonal bipyramidal coordination with the bridging oxygen atom and the arenesulfonate group in axial positions. The Bi-C and Bi-O_term distances are 2.200(2), 2.204(3), and 2.442(2) Å, and the Bi-O_br distances are 2.067(1) Å.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 9, 2004, pp. 1466–1471.Original Russian Text Copyright © 2004 by Sharutin, Egorova, Sharutina, Ivanenko, Pavlushkina, Gerasimenko, Pushilin.This revised version was published online in April 2005 with a corrected cover date.     

Synthesis and characterization of poly(styrene/α-t-butoxy-ω-vinylbenzyl-polyglycidol) microspheres

Polystyrene microspheres with polyglycidol (polyGL) in a surface layer were synthesized in batch radical emulsifier-free emulsion copolymerizations of styrene and surfmers, α-t-butoxy-ω-vinylbenzyl-polyGL macromonomers (VB-polyGL). Macromonomers with number-average molecular weight Mˉ _n=950 (VB-polyGL950) and Mˉ _n=2700 (VB-polyGL2700) were used for these polymerizations. In all syntheses the initial concentrations of styrene and initiator (K₂S₂O₈) were constant. The initial macromonomer-to-styrene ratios were varied from 1.10 × 10⁻³ to 1.64 × 10⁻² mol/mol and from 3.46 × 10⁻⁴ to 3.47 × 10⁻³ mol/mol for VB-polyGL950 and VB-polyGL2700, respectively. The diameters of microspheres obtained were smaller for the syntheses with higher concentrations of macromonomers. Syntheses with VB-polyGL950 yielded microspheres with number-average diameters (Dˉ _n) from 216 to 900 nm and with a bimodal diameter distribution. The number-average diameters of microspheres obtained with VB-polyGL2700 varied from 220 to 650 nm, depending on the initial concentration of macromonomer. Their diameter distributions were monomodal, with a diameter polydispersity parameter (ratio of weight-average and number-average diameters) in the range 1.007≤Dˉ _w/Dˉ _n≤1.022. For each type of microsphere the fraction of polyGL in a surface layer and the surface concentration of sulfate anions were determined. The fraction of polyGL in the surface layer was related to the initial monomer composition in the polymerizing mixture. Adsorption of human serum albumin onto surfaces of some poly(styrene/VB-polyGL) microspheres was up to 10 times lower than for the polystyrene microspheres obtained in a similar emulsifier-free emulsion polymerization of styrene. Received: 26 September 2000/Accepted: 19 February 2001     

Synthesis and chemical properties of cyclic β-keto sulfones (review)

Published data on the synthesis and chemical properties of dihydrothiophen-3(2H)-one 1,1-dioxide, dihydro-2H-thiopyran-3(4H)-one 1,1-dioxide, 1-benzothiophen-3(2H)-one 1,1-dioxide, and 1H-isothio-chromen-4(3H)-one 2,2-dioxide are reviewed. The choice of subjects was based on the presence of identical structural fragments, carbonyl, active methylene, and sulfonyl groups.     

Synthesis of keto acids from olefins andω-chloroformyl carboxylic esters

Summary The following were synthesized for the first time by the catalytic method from the corresponding alkene and acid chloride; 1) 6-oxo-7-decenoic acid; 2) 8-methyl-6-oxo-7-nonenoic acid; 3) 4-oxodecanoic acid; 4) 6-oxododecanoic acid; 5) 7,7,8-trimethyl-6-oxo-8-nonenoic acid; 6) 7,7,8-trimethyl-6-oxononanoic acid; 7) 6-oxotridecanoic acid (this acid was prepared previously by organomagnesium synthesis [4]).     

Synthesis of 2-amino-3,6-di(het)arylpyridines from 5-cyano-3,6-di(het)aryl-1,2,4-triazines and arylhydrazines via the SNipso/aza-Diels–Alder reaction sequence

Reaction between 5-cyano-3,6-di(het)aryl-1,2,4-triazines and arylhydrazines with the following aza-Diels–Alder autoclave reaction affords hardly available 2-amino-3,6-di(het)aryl-pyridines in up to 67% yield after two steps and in 75% yield for the one-pot way. The compounds obtained can be promising for medicinal chemistry.     

Selective synthesis of cyclic triperoxides from 1,1′-dihydroperoxydi(cycloalkyl)peroxides and acetals using SnCl4

Russian Chemical Bulletin - A method for the synthesis of 1,2,4,5,7,8-hexaoxonanes by the reaction of 1,1′-dihydroperoxydi(cycloalkyl)peroxides with acetals using SnCl4 has been developed....     

Halogenated catechols from cycloaddition reactions of η-(2-ethoxyvinylketene)iron(0) complexes with 1-haloalkynes

1-Chloroalkynes and 1-bromohexyne undergo cycloaddition reactions with ethoxyvinylketeneiron(0) complexes to form chloro and bromocatechols. With most substituents, the halogen is incorporated ortho to the phenolic hydroxyl group regioselectively. With chloroethyne, chlorohexyne, and methyl chloropropiolate, the reverse regioselection is observed. Ab initio calculations reveal that the products are, in most cases, nearly isoenergetic, which indicates that the intermediate ketene-alkyne adduct geometry must be important in determining the product distribution.     

Synthesis of new homochiral 2,3-dialkylpiperazines derived from (R)-(−)-phenylglycinol

The synthesis of four new 2,3-dialkylpiperazines in yields of 70–99% using (R)-(−)-phenylglycinol as a chiral inductor is described. The synthesis involved reduction of the oxazino–oxazine type derivatives obtained by condensation of glyoxal and phenylglycinol to give hydroxyethylenediamine precursors which were further condensed with glyoxal, butanedione and 1-phenyl-1,2-propanedione and then reduced to provide the corresponding piperazines. The stereochemical outcome is determined by the configuration of the bisoxazolidine precursors, which is in turn dictated by steric effects exerted by the substituents on the five membered ring. The structures of five derivatives were established by X-ray analysis.     

Synthesis and reactions of 9-hydroxy-(α-alkoxycarbonylalkyl)-4-azafluorenes

The Reformatsky reaction with 4-azafluorenone has given 9-hydroxy-9-(-alkoxycarbonylalkyl)-4-azafluorenes. The course of this reaction with respect to the -haloester used, and the conversion of these hydroxyesters into hydroxy- and ,-unsaturated acids have been examined.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 81–85, January, 1991.     

Synthesis and photophysical properties of α,ω-bis(terpyridine)oligothiophenes

Four novel fully π-conjugated α,ω-bis(terpyridine)oligothiophenes characterized by NMR, IR, and HR-mass spectroscopy are presented and their electronic absorption/emission and redox properties are described based on both experiments and theoretical calculations. These compounds can be potentially utilized as building blocks for preparation of conjugated metallo-supramolecular polymers or dynamers and related functional materials.     

Synthesis of substituted naphthalenes from α-substituted ketones and 1,2-bis(halomethyl)benzenes including a rearrangement aromatization of benzo[c]oxepine

An efficient and practical method for the synthesis of cyano, sulfonyl and phosphoryl substituted naphthalene derivatives via the rearrangement aromatization of benzo[c]oxepine has been developed. The system holds the advantages of metal catalysts free, and mild reaction conditions.     

Synthesis and mesomorphic properties of 4-(4-bromopropyloxy)-4’-(4-alkyloxybenzylidene)anilines

This article describes the preparation and liquid crystalline properties of a new homologous series of 4-（4-bromopropyloxy）-4’- （4-alkyloxybenzylidene）anilines in which the phenyl ring is armed by a bromopropyloxy chain.The thermal behavior and mesomorphic properties of the synthesized compounds were studied with particular attention given to the correlation between their phase transition temperatures and anisotropic change influenced by molecular structure.All the members displayed enantiotropic smectic phase except for the homologue with the longest alkyloxy chain(R = C₁₈H₃₇),exhibiting only monotropic characteristic. The presence of bromine atom from the propyloxy side chain is found to be capable of altering and influencing the mesomorphic properties.     

Synthesis,structure, and properties of anhydrous organic-inorganic proton-exchange membranes based on sulfonated derivatives of octahedral oligosilsesquioxanes and α,ω-di(triethoxysilyl) oligo(oxyethylene urethane urea)

A method of obtaining new organic-inorganic nanostructured proton-exchange membranes operating via the anhydrous proton-conduction mechanism is proposed. An oligo(ethylene oxide) component serves as a proton-conducting phase in these membranes, and the sulfo derivatives of octahedral oligosilsesquioxanes of the acidic and acid-base types are used as proton-donor dopants. These compounds are synthesized via the reaction of octaaminopropyl oligosilsesquioxane with the cyclic anhydride of 2-sulfobenzoic acid at various ratios and contain sulfo groups solely or sulfo and amine groups in the organic frame. The combination of these compounds taken at concentrations of 20 and 50 wt % with α,ω-di(triethoxysilyl) oligo(oxyethylene urethane urea) and phenyltriethoxysilane via the sol-gel method gives rise to hybrid organic-inorganic proton-exchange membranes. The synthesized dopants are distributed in the oligoether component, but the nature of dopant distribution depends on their structure and concentration and has a significant impact on the structure of the resulting amorphous membranes (according to DSC, SAXS, and AFM data). The synthesized membranes are thermally stable up to 219°C. Their conductivity is provided by the segmental mobility of oligooxyethylene fragments (the Grotthuss mechanism) and, regardless of the dopant structure, is primarily determined by the number of charge carriers and the membrane structure. The temperature dependence of the conductivity is described by the Vogel-Fulcher-Tammann equation. The maximum values of the ionic conductivity are attained at 120°C under anhydrous conditions and dopant concentration of 50%: 1.03 × 10^?4 for ampholytic oligosilsesquioxane and 7.43 ×10^?5 S/cm for fully sulfonated oligosilsesquioxane as a dopant.     

Synthesis and Properties of Cobalt(II) Tetrakis-[4,5-di(4′-carboxy)phenylene(oxy/sulfanyl/amino)]phthalocyanines

Russian Journal of General Chemistry - Phthalonitriles with fragments of 4-hydroxy, 4-mercapto and 4-aminobenzoic acids were synthesized by nucleophilic substitution in...     

Synthesis and domino reactions of polymethylene-3-cyanopyridine-2(1Н)-thiones

A new and facile three-component method was developed for the synthesis of polymethylene-3-cyanopyridine-2(1Н)-thiones by the domino Knoevenagel → Michael → heterocyclization → dehydrogenation reaction from cycloalkanones, cyanothioacetamide, and polymethoxy-substituted benzaldehydes. The final dehydrogenation step was found to involve arylidenecyanothioacetamide. The resulting pyridinethiones and 4-chloroacetoacetic ester were introduced into the domino S_N2 → Thorpe-Ziegler → Guareschi-Thorpe reaction to synthesize tetracyclic dipyridothiophenes. Starting from these compounds, 8,9-polymethylenepyranothienodipyridines were also synthesized by the domino Knoevenagel → Michael → hetero-Thorpe-Ziegler reaction. Furthermore, a method for the synthesis of thienodipyridine annulated to the steroid skeleton is proposed.