Resolution of 1-arylalkylamines with 6-(1,2:3,4-di-O-isopropylidene-α-d-galactopyranosyl)hydrogen phthalate

The resolving ability of a new acidic resolving agent, the hydrogen phthalate of 1,2:3,4-di-O-isopropylidene-α-d-galactopyranose 1, against various 1-arylalkylamines 2a–k is described. Treatment of 1 with amines 2a–f to obtain diastereomeric salts 1·(S)2a–f in 2-propanol allowing the corresponding (S)-amines 2a–f to be recovered in good yield and 61–89% ee. Recrystallization in dichloromethane/hexane, and regeneration gave the amines in enhanced enantiomeric purity (>98% ee). 1 resolved 1-phenylpropylamine 2f in high enantiomeric purity (99% ee) than 1-phenylethylamine 2g (11% ee) and o- and m-methoxy 2h–i, o-chloro-2j and p-fluoro-2k substituted 1-arylamines (11–19% ee). A possible chiral recognition mechanism based on the ability of 1 to exist in two conformations is described.     

Synthesis and Spectroscopic Properties of Cyclotriphosphazenes Containing 6-(4-Hydroxyphenyl)-2,2''-bipyridine Side Groups

Two novel cyclotriphosphazene derivatives containing 6-(4-hydroxyphenyl)-2,2'-bipyridine(hopbp)side groups,N_3P_3(dobp)_2(hopbp)_2(1)and N_3P_3(dobp)(hopbp)_4(2)(dobp=2,2'-dioxybiphenyl),were synthesized and characterized.These compounds display strong fluorescent emission both in solution and in solid state.Their absorption and emission spectra are sensitive to proton:the addition of HBF4 to the methanol and dichloromethane solution(9∶1,volume ratio)of compound 1 led to a red-shift from 350 to 460 nm for the emission spectrum,and the process was also characterized by isosbestic points of absorption spectra at 267,287 and 313 nm.     

Synthesis of a (1→6)-β-Linked N-Acetyl-d-glucosamine Oligosaccharide1

Abstract

1,6-Anhydro-2-deoxy-3,4-di-O-benzyl-2-phthalimido-β-d- glucopyranose (5) was synthesized from 1,6-anhydro-β-d-mannopyranose (1) in five steps. Compound 5 was polymerized under cationic conditions and selectively yielded glucosamine oligomers (degree of polymerization 5-7). Copolymerization of 5 with 1,6-anhydro-2,3,4-tri-O-benzyl-β-d-glucopyranose indicated the low reactivity of 5 with the active cation derived from 5. Deprotection of 2-deoxy-3,4-di-O-benzyl-2-phthalimido-(1→6)-β-d-glucopyranan (7) and N-acetylation gave 2-acetamido-2-deoxy-(1→6)-β-d-glucopyranan (9).     

Synthesis of an antimetastatic tetrasaccharide β-D-Gal-(1→4)-β-d-GlcpNAc-(1→6)-α-D-Manp-(1→6)-β-D-Manp-OMe

An antimetastatic tetrasaccharide T₁,β-D-Gal-（1→4）-β-D-GlcpNAc-（1→6）-α-D-Manp-（1→6）-β-D-Manp-OMe,was synthesized with two approaches.The first approach was a conventional method employing thioglycoside and Koenigs-Knorr glycosylation reaction in 24%overall yield.The second one was a novel route through the azidoiodo-glycosylation strategy by using 2-iodo-2-deoxylactosyl azide as the donor in 36%overall yield.     

Synthesis of Polyacrylamide Copolymers Containing (1→6)-Branched (1→3)-β-D-Linked Tri- and Tetra-Saccharides Related to Schizophyllan

Abstract

The allyl β-glycosides of a trisaccharide O-β-D-Glcp-(1→3)-O-[β-D-Glcp-(1→6)]-β-D-Glcp and of a tetrasaccharide O-β-D-Glqp-(1→3)-O-[β-D-Glqp-(1→6)]-O-β-D-Glcp-(1→3)-β-D-Glcp, corresponding to the branching point or the repeating unit of antitumor (1→6)-branched-(1→3)-β-D-glucans, have been synthesized starting from ethyl 2-O-benzoyl-4,6-O-benzylidene-l-thio-α-D-glucopyranoside and copolymerized in a radical reaction with acrylamide to obtain polyacrylamide copolymers containing the tri-and tetra-saccharides for immunochemical studies of schizophyllan.     

Synthesis and Acid-Base Properties of Tetraphenylporphine Derivatives with Amino Acid “Anchor” Groups

Russian Journal of General Chemistry - Asymmetrically substituted 5,10,15,20-tetraphenylporphyrin derivatives such as 5-(4-aminophenyl)10,15,20-triphenylporphine,...     

Synthesis of (1→5)-β-d-galactofuranan and cyclo[(1→5)-β-d-galactofurano]oligosaccharides

Synthesis of a linear (1→5)-β-d-galactofuranan was accomplished by trityl-cyanoethylidene polycondensation. On 10-fold reduction in the monomer concentration, the condensation products are cyclic oligosaccharides; the formation of 1,5-anhydro-α-d-galactofuranose was also demonstrated.     

Coordination Assemblies of Cd~(Ⅱ) with 5-(Ethylthio)-1H-tetrazole and Halide Ions: Synthesis,Structure, and Luminescent Properties

Three cadmium(II)-halide complexes with 5-(ethylthio)-1H-tetrazole(Hett) as ligand, namely [Cd_7Cl_2(ett)_(12)(H_2O)_2]_n(1), [Cd_2(OH)Br(ett)_2]_n(2) and [Cd_2(OH)I(ett)_2]_n(3), have been hydrothermally synthesized and characterized. Complex 1 was synthesized at pH = 7 and exhibits a 3D supramolecular framework, where the adjacent Cd ions form a tetrahedron unit by ett ligands bridge and the tetrahedron units share vertices to connect each other by ett bridges to form a 2D layer architecture, which is further interlinked by μ_2-Cl to form 3D structures. Complexes 2 and 3 are isostructural, generated at pH = 8.0~9.0, displaying similar 2D networks via ett ligands and different halide ions(Br-in 2, I-in 3, respectively). In addition, thermal stabilities and luminescent properties of new complexes 1~3 have been studied.     

Sonochemical Synthesis of 5,6-Dihydro[C70-D5h(6)][5,6](1,4- dioxano)fullerene by Reaction of Fullerene with α-Diols

Russian Journal of Organic Chemistry - A procedure has been developed for the sonochemical synthesis of 5,6-dihydro[C70-D5h(6)][5,6]- (1,4-dioxano)fullerene on the basis of heterogeneous reaction...     

Synthesis and Structure of 1,2-O-(1-Aryl-1-Propylidene)-D-Mannitol

KetaloracetalfonnationoproachingwiththecarbohydrasasreactantSarenowfrequentiyusedasanmprtanSyntheticmethodforprotedngofkbonesinthecourseforpreParationOfvariousmul~ctionalcomPlexorgamcmoledesl1-5].ThereaedonOfcyclicoraCyclicchiralcaIbohydrtesandtheirderivativeswithnon-methylarylketonescannotonlyproteCtndnylgrouPinarelkeone.butalsoInaketheira-carbonSUbedtutedcompoundstodiastercoisomericisomers,themolecularisomerscanalsobeeasilyconVertotinacontrolledfashion,toaseriesofpurelymul~edonalchiralm…     

Synthesis and Antimicrobial Properties of the Novel Fluorinated Bis-ammonium Salts with Two Primary Amine Groups

In order to resolve the increasing resistance phenomena of the Gram-negative bacteria against single chain quaternary ammonium salts （QAS）, lysine with a pedant fluorinated bis-ammonium salts was synthesized and its antimicrobial properties were evaluated in this work. The novel fluorinated bis-ammonium salts shows similar activity with conventional single chain quaternary ammonium salts against Gram-positive bacteria but stronger activity against Gram-negative bacteria and yeast compared with the single chained counterpart.     

Synthesis and Antimicrobial Properties of the Novel Fluonnated Bis-ammonium Salts with Two Primary Amine Groups

In order to resolve the increasing resistance phenomena of the Gram-negative bacteria against single chain quaternary ammonium salts (QAS), lysine with a pedant fluorinated bis-ammonium salts was synthesized and its antimicrobial properties were evaluated in this work. The novel fluorinated bis-ammonium salts shows similar activity with conventional single chain quaternary ammonium salts against Gram-positive bacteria but stronger activity against Gram-negative bacteria and yeast compared with the single chained counterpart.     

Synthesis and Spectroscopic Properties of Cyclotriphosphazenes Containing 6-（4-Hydroxyphenyl）-2,2′-bipyridine Side Groups

Two novel cyclotriphosphazene derivatives containing 6- （4-hydroxyphenyl）-2,2′-bipyridine （hopbp） side groups, N3 P3 （dobp） 2 （hopbp） 2 （ 1 ） and N3 P3 （dobp） （hopbp） 4 （2） （ dobp = 2,2′-dioxybiphenyl）, were synthesized and characterized. These compounds display strong fluorescent emission both in solution and in solid state. Their absorption and emission spectra are sensitive to proton： the addition of HBF4 to the methanol and dichloromethane solution（9： 1, volume ratio） of compound 1 led to a red-shift from 350 to 460 nm for the emission spectrum, and the process was also characterized by isosbestic points of absorption spectra at 267, 287 and 313 nm.     

Synthesis of Two Isomeric Tetrasaccharides 0-α-L-Fucopyranosyl-(1→3) and (1→4)-0-(2-Acetamido-2-Deoxy-β-D-Glucopyranosyl)-(1→3)-0-(β-D-Galactopyranosyl)-(1→4)-D-Glucopyranose and a Related Tetrasaccharide 0-α-L-Fucopyranosyl-(1→3)-0-(2-Acetamido-2-Deoxy-β-D-Glucopyranosyl-(1→6)-0-(β-D-Galactopyranosyl)-(1→4)-D-Glucopyranose

ABSTRACT

Synthesis of three tetrasaccharides, namely, 0-α-L-fucopyranosyl-(1→3)-0-(2-acetamido-2-deoxy-β-D-glucopyranosyl)-(1→3)-0-(β-D-galactopyranosyl)-(1→4)-β-D-glucopyranose (7), 0-α-L-fucopyranosyl-(1→4)-0-(2-acetamido-2-deoxy-β-D-glucopyranosyl)-(1→3)-0-(β-D-galactopyranosyl)-(1→4)-D-glucopyranose (9), and 0-α-L-fucopyransoyl-(1→3)-0-(2-acetamido-2-deoxy-β-D-glucopyransoyl)-(1→6)-0-(β-D-galactopyranosyl)-(1→4)-D-glucopyranose (15) has been described. Their structures have been established by ¹³C NMR spectroscopy.     

Synthesis and Properties of D-Thymidylyl (3'→5')L-Thymidine (D/L-TpT)

Inrecentyearsmuchefforthasbeenspenttodevelopoligonucleotideanalogsashighlyselectivepharmaceuticalagentstoblockexpressionofdisease-associatedproteins'-'.andtheseefT'ortshaveresultedilltheapprovaloffomiversensodium(vitravene',"),thefirstantisensedrug,byFDAinAugust1998fortreatmentofAIDSpatientswithcytomegalovirus(CMV)-inducedretinitis6.However,thegreatpotentialofantisenseoligonucleotidesasantiviralandanticanceragentsiscompromisedbytheirnucleasesusceptibilityandlowcellmembranepermeability.L-D…     

Synthesis of Pyrazoles by the Condensation of C(α)- and Trianions with Esters

In addition to our previous papers^2,3 on the preparation of pyrazoles from the C(α), N-dianions of phenylhydrazones and C(α), N, N-trianions of hydrazones, we wish to report preliminary results on (I) the preparation and condensation of methylhydrazone dianions with methyl benzoate followed by acid cyclization, (II) the condensation of the dianions of phenylhydrazone with methylformate, and the preparation and condensation of the trianions of cyclopentanone (III) and α - tetralone (IV) hydrazones.     

Synthesis, Mesogenic and Spectroscopic Properties of 2,5-Disubstituted Thiophene Derivatives

Two series of 2,5-disubstituted thiophene derivatives （series 1： 2,5-bis（p-alkoxyphenylethynyl）thiophene and series 2： 2,5-bis[p-（p-alkoxyphenylethynyl）（phenylethynyl）]thiophene） were synthesized and characterized by ^1H NMR, ^13C NMR, HRMS and elemental analysis. The relationship between the structure and the mesogenic and spectroscopic properties has been discussed. The results show that compounds 1a-1f all exhibited an enantiotropic nematic mesophase, which was confirmed by the polarized optical microscopy （POM）, differential scanning calorimeter （DSC） and variable temperature powder X-ray diffraction （PXRD）. In contrast, the extended conjugated analogues 2a-2b had no liquid crystal properties. As for the spectroscopic properties, incorporating more phenylethynyl units results in red-shifted absorption and emission spectra, greatly enhanced quantum efficiency.     

Synthesis and Adsorption Properties of Chelating Resins Containing Sulfoxide and Heterocyclic Functional Groups

Chelating resins containing heterocyclic functional groups and sulfoxide show high affinity for heavy and noble metal ions, so many attempts are under way to anchore such groups onto solid supports1-3. The earlier studies were on the resins containing het…     

Synthesis and Crystal Structure of 2-(4-Nitrophenyl)-1,2-benzisoselenazol-3(2H)-one DMF (1:1) Solvate

The title compound (C13H8N2O3Se-C3H7NO) has been synthesized by a simple synthetic route and by recrystallization from DMF. The molecular structure of this compound was obtained by single-crystal X-ray diffraction. The compound crystallized in the triclinic space group P with a = 7.450(6), b = 8.150(7), c = 13.859(12) , α = 75.014(14), β = 83.072(18), γ = 84.409(14)°, V = 805.0(12)3, Z = 2 and R = 0.0271 for 2575 observed reflections with I > 2σ(I). X-ray analysis reveals that not only intermolecular Se…O and C-H…O interactions, but also π…π stacking interactions exist in the adjacent molecules. The above three kinds of intermolecular interactions extend the complex into an infinite three-dimensional layered network.