Synthesis of a New Isoflavone: 7,8,4′-Trihydroxyisoflavone

Isoflavones have been found a wide range of applications as natural antioxidants being suggested in diet as a gents responsible for the prevention of coronary diseases, breast and prostate cancer. [1] Most of the isoflavones have been isolated from natural sources and their simple structural features lead to the development of many synthetic methods. [2] Here we synthesized a new trihydroxyisoflavone.     

A new synthesis of 3′-deoxy-3′-fluoroadenosine,a key intermediate of cyclic dinucleotide

A new synthesis of 3′-deoxy-3′-fluoroadenosine for use as an important intermediate of antitumor-active cyclic dinucleotide is disclosed. The synthesis started with the known 5-O-TBDPS-D-lyxofuranose 1,2-acetonides, which was first transformed into a fluorinated compound after the DAST reaction. Desilylation and acidic methanolysis were then finished in one pot. After a sequence of triflation, displacement by OBz as well as benzoylation, perbenzoylated 3-deoxy-3-fluoro-D-ribofuranoside was obtained, which would be transformed to 3′-deoxy-3′-fluoroadenosine as the key intermediate of cyclic dinucleotide after ammonolysis.     

Synthesis and liquid crystalline behavior of a series of ferrocene 1,1′-bis-azino-derivatives

A series of liquid-crystalline ferrocene derivatives, Fe{C₅H₄-C(CH₃)=N-N=CH-C₆H₃(X)-OOC-C₆H₄-OC _n H_2n+1}₂ (X = H, OH;n = 3 to 12), were obtained by the condensation of 1,1 -bishydrazondiacetylferrocene withp-alkoxybenzoyloxybenzaldehides. According to DSC and polythermic microscopy, all of the compounds exhibit an enantiotropic nematic mesophase in the 150–230 °C temperature range. A polycrystalline transition precedes the nematic transition. The liquid crystalline properties of the obtained compounds were investigated with respect to the number of carbon atoms in the terminal alkyl chain and the terminal hydroxyl group. The composition and structure of the obtained compounds were determined by elemental analysis and IR and NMR spectroscopy.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 358–361, February, 1995.This work was carried out with financial support from the Russian Fundation for Basic Research (Project No. 94-03-08978).     

2,2′-Dialkoxy, 2,2′-dihydroxy,and 2,2′-diamino derivatives of 1,1′-azobenzimidazole. The first synthesis of heterocyclic tetrazenes by means of a nucleophilic substitution reaction

2,2-Dimethanesulfonyl-1,1-azobenzimidazole is prepared by the oxidation of 1-amino-2-methanesulfonylbenzimidazole with lead tetraacetate. The reaction of this tetrazene with alkali in DMSO, with sodium alkoxides in the corresponding alcohol or ammonia, or with primary or secondary amines leads to the formation of 2,2-dihydroxy, 2,2-dialkoxy, or 2,2-diamino derivatives of 1,1-azobenzimidazole.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 190–193, February, 1992.     

Synthesis of hydrogels from a polymeric N,N′-diallyl-N,N′-dimethylammonium salt

Feasibility in principle has been demonstrated for obtaining hydrogels with controlled parameters of the three-dimensional network by copolymerization of N,N-methylenebisacrylamine with macromolecules of poly-N,N-diallyl-N,N-dimethylammonium chloride containing terminal double bonds, i.e., with macromonomers of N,N-diallyl-N,N-dimethylammonium chloride. The hydrogels that are obtained have high anion-exchange capacities.A. V. Topchiev Institute of Petrochemical Synthesis, Academy of Sciences of the USSR, Moscow 117912. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 4, pp. 851–854, April, 1992.     

Diastereoselective aminocarbonylation of a steroidal iodoalkene with 2,2′-diamino-1,1′-binaphthalene in palladium-catalysed reactions

A palladium-catalysed aminocarbonylation of a steroidal iodoalkene (17-iodo-5α-androst-16-ene) model compound with 2,2′-diamino-1,1′-binaphthalene as an N-nucleophile was carried out. The combination of a steroidal skeleton possessing central elements of chirality and a binaphthyl moiety with axial chirality was carried out resulting in a novel type of steroidal carboxamides. The binaphthalene—steroid conjugates are potential 5α-reductase inhibitors. Both epimers of the monocarboxamide and those of the dicarboxamide, formed with moderate diastereoselectivity, were isolated and fully characterised.     

Synthesis of a Diterpene 1,3,4-Oxadiazolin-2′-one from Dimethylcyclopentenonepimarate

A diterpene 1,3,4-oxadiazolin-2-one was synthesized by lead-tetraacetate oxidation of 16,17- epoxydimethylcyclpentenonepimarate. The structures of the synthesized compounds were confirmed by IR and NMR spectroscopies.     

Total synthesis of baiyunoside by a novel 2′ discriminated glycosidation

Total synthesis of a sweet taste glycoside with labdane diterpenoid, baiyunoside (1), has been accomplished from (±)-baiyunol (2) by a novel 2′ discriminated glucosidation using 3b followed by the introduction of xylosyl moiety using 3c according to Noyori's procedure.     

Hydrothermal synthesis and characterization of a zigzag neodymium-2,2′-bipyridine-3,3′-dicarboxylate-isonicotinate coordination polymer

A new neodymium(III) coordination polymer, {[Nd(bpdc)(iso)(H₂O)₂] ? (H₂O)_2.25} _n (1), was synthesized by treating neodymium oxide with 2,2′-bipyridine-3,3′-dicarboxylic acid (H₂bpdc), and isonicotinic acid (Hiso) under hydrothermal conditions. Single-crystal X-ray diffraction shows that 1 is a 1-D zigzag chain and extends to 2-D network structure through π–π interactions and hydrogen bonds. Thermogravimetric analysis of 1 displays a considerable thermal stability. The variable-temperature magnetic susceptibility of 1 was measured.     

Synthesis of 3-pyrrol-3′-yloxindoles with a carbamate function

By the reaction of methyl {4(3)-[2-(2-oxo-1,2-dihydro-3H-indol-3-ylidene)acetyl]phenyl} carbamates with ethyl 3-aminocrotonate at boiling in the mixture toluene-anhydrous ethanol, 2: 1, ethyl 5-{3(4)-[(methoxycarbonyl)amino]phenyl}-2-methyl-4-(2-oxo-2,3-dihydro-1H-indol-3-yl)-1H-pyrrole-3-carboxylates were obtained. The condensation of methyl {3(4)-[2-(2-oxo-1,2-dihydro-3H-indol-3-ylidene)acetyl] phenyl}carbamates with ethyl acetoacetate in the presence of ammonium acetate and 20 mol% of 1-methyl-3-butylimidazolium chloride or 1-methyl-3-octylimidazolium tetrafluoroborate at boiling in anhydrous ethanol led to the formation of the corresponding 3-pyrrol-3′-yloxindoles with a carbamate function.     

Preparation and resolution of 2,2′-dimercapto-6,6′-dimethoxy-1,1′-biphenyl: a C2-symmetric sulfur building block

The preparation of the title dimercaptan 1 starting from 2,2′-dihydroxy-6,6′-dimethoxy-1,1′-biphenyl 2 is described. Resolution of dimercaptan 1 was performed using (−)-(1R,2S,5R)-menthyl chloroformate as a chiral resolving agent. The procedure affords dimercaptan (+)-1 and (−)-1 in 98% ee and 93% ee, respectively. A new and direct intermolecular Ullmann coupling resulting in an improved preparation of diol 2 is also reported.     

The Synthesis of a New Dumbbell-shaped Compound of Bis-4, 4′-bipyridine Bridged by 2, 2′-Bipyridine

The title compound 5 was synthesized in 45% yield by the reaction of compound 3 with α,α′-bis (bromomethyl)-2, 2′-bipyridine in CH3CN at 70℃ for 24 h.     

A feature of reaction of 1,1′-diacetylferrocene with dimethylformamide dimethyl acetal leading to a new strategy of the synthesis of asymmetrical 1,1′-disubstituted ferrocene

The reaction of 1,1′-diacetylferrocene with the dimethylformamide dimethyl acetal proceeds regioselectively to afford [1-acetyl-1′-(1-dimethylamino-3-oxoprop-1-en-3-yl)]ferrocene, based on which new approaches to the synthesis of 1,1′-disubstituted unsymmetrical ferrocene derivatives via the reaction with nucleophilic reagents hydrazine hydrate, hydroxylamine, and amidines were developed.     

Expression and Purification of Biologically Active Human FGF2 Containing the b′a′ Domains of Human PDI in Escherichia coli

Among the members of the fibroblast growth factor (FGF) family that affect the growth, differentiation, migration, and survival of many cell types, FGF2 is the most abundant in the central nervous system. Because of its wound healing effects, FGF2 has potential as a therapeutic agent. The protein is also added to the culture media to maintain stem cells. Expression and purification procedures for FGF2 that are highly efficient and low cost have been intensively investigated for the past two decades. Our current study focuses on the purification of FGF2 fused with b′a′ domains of human protein disulfide isomerase to elevate overexpression, solubility, and stability with a simplified experimental procedure using only ion exchange chromatography, as well as on the confirmation of the biological activity of FGF2 on fibroblast Balb/c 3T3 cells and hippocampal neural cells.     

A new example of reversal of the order of migration of enantiomers, as a function of cyclodextrin concentration and pH, by cyclodextrin-modified capillary zone electrophoresis: enantioseparation of 6,6′-dibromo-1,1′-binaphthyl-2,2′-diol

Enantioseparation of 6,6′-dibromo-1,1′-binaphthyl-2,2′-diol (DBBD) by cyclodextrin-modified capillary zone electrophoresis (CD-CZE) was studied using the three native α, β, and γ cyclodextrins, the three hydroxypropylated cyclodextrins (2-hydroxypropyl-α, β, and γ), heptakis-2,6-di-O-methyl-β-CD (DM-β-CD), and heptakis-2,3,6-tri-O-methyl-β-cyclodextrin (TM-β-CD). First, the acidity constants of DBBD were determined using capillary electrophoresis, before performing enantioseparation. The influence of the concentrations of the studied cyclodextrins on the enantioseparation was explored and the experimental optimal concentrations were determined and compared to the theoretical optimal concentrations. Moreover, the apparent complexation constants between each studied cyclodextrin and the two DBBD enantiomers were evaluated using a non-linear curve fitting method and three linear plotting methods (x-reciprocal, y-reciprocal and double reciprocal). For TM-β-CD, the order of migration of the enantiomers of DBBD reversed as a function of TM-β-CD concentration. The influence of the nature of methylated cyclodextrin derivatives (methyl-β-CD (M-β-CD) and DM-β-CD) was then studied. Inversion of the order of migration of the enantiomers of DBBD was observed for DM-β-CD, whereas the S enantiomer of DBBD always migrated first for M-β-CD.     

Synthesis of enantiomerically pure carbocyclic 3′-azido-2′, 3′-dideoxythymidine,a potential anti-aids drug

(+)-1-[(1R,3S,4S)-3-Azido-4-(hydroxymethyl)cylopentyl]-5-methyl- 2,4-(1H,3H)-pyrimidindione 7 (C-AZT) was synthesized starting from mesylated compound 1 in a six step sequence via urea derivative 5.     

Structures of the crystalline supramolecular associates of imidazole with 1,1′-binaphthyl-8,8′-dicarboxylic acid and 2,2′-dihydroxy-1,1′-binaphthyl. Spatial similarity of the acid associate crystal packing to the active site of a serine protease

Abstract

Crystal structure analysis of the imidazole associates with 1,1′-binaphthyl-8,8′-dicarboxylic acid (1), [1a, triclinic, P1, a = 7.569(4), b = 8.393(2), c = 8.634(1) Å, α = 93.21(2), β = 106.88(3), γ = 105.17(3)°, D_c = 1.36 g/cm³, Z = 1, R = 0.045 for 1031 data] and with 2,2′-dihydroxy-1,1′-binaphthyl (2), [2a, tetragonal P4₁2₁2, a = 8.519(1), c = 29.821(2), D_c = 1.30 g/cm³, Z = 4, R = 0.051 for 1236 reflections] revealed 1:1 and 1:2 stoichiometry, respectively. Spontaneous resolution occur during crystallization in both compound crystals. 1a is a salt-like associate with hydrogen bonds between the carboxylate and imidazolium ion pairs while the neutral 2a has also well defined hydrogen bonds between host and guest molecules. In a modeling experiment corresponding Brookhaven Protein Data Bank atomic coordinates from the active site of the bacterial serine protease enzyme Subtilisin BPN were fitted to the crystal packing of the small molecule associate 1a crystal. The relative displacement of the ion pair components and a symmetry related carboxyl function in 1a has fair steric resemblance to similar moieties in the active site of Subtilisin (Δ_ave = 0.24 Å for 9 fitted atoms). The agreement in the results of two fully independent and totally different (i.e. a native protein active site and an artificial small molecule associate) crystal structure determinations underlines the assumed conceptual similarity of crystals (“giant supramolecules”) to protein sequences optimized through evolution.     

Application of a novel 1,1′-dimethylferricinimum dye for the determination of uric acid in urine

Water-soluble 2-hydroxypropyl-β-cyclodextrin (Hp-β-CyD), a cyclic and nonreducing oligosaccharide was used to enclose a hydrophobic guest molecule 1,1′-dimethylferrocene (DMF) to form a water-soluble yellow complex. At high concentrations (300 mM), Hp-β-CyD enclosed up to 100 mM DMF. The yellow complex was electrochemically oxidized (platinum vs Ag/AgCl poised at +450 mV) to form a blue dye, 1,1′-dimethylferricinium (DMF⁺). This is a one-electron transfer process and the ferricinium cation formed exhibited an absorption peak at 650 nm. The concentrated DMF⁺ was stable for at least 4 mo at 4°C and insensitive to a wide pH variation (pH 2–11). Application of the novel DMF⁺ complex as a colorimetric dye for the determination of uric acid in urine was successfully demonstrated. The reaction between the dye and uric acid is almost instantaneous and decrease in absorbance caused by the reduction of 1,1′-dimethylferricinium to 1,1′-dimethylferrocene can be followed at 650 nm. The results obtained agreed well with those of the reference reversed-phase HPLC method.     

The rate of cyclization of 2′- and 4′-substituted diphenylamine-2-carboxylic acids in sulfuric acid as a function of the electronic properties of substituents

The kinetic regularities of cyclization of 2′- and 4′-substituted diphenylamine-2-carboxylic acids in sulfuric acid were determined. The rate of cyclization of diphenylamine-2-carboxylic acids is linearly dependent on the nature of substituents in the meta-position relative to the reaction site in accordance with the two-parameter Hammett equation.