Polyurethane Molecular Stamps for the in situ Synthesis of DNA Microarray

Fabrication of polyurethane molecular stamps (PU stamps) based on polypropylene glycol (PPG) and toluene dissocyanate (TDI), using 3,3′-dichloro-4,4′-methylenedianiline (MOCA) as the crosslinker ,is reported. It was shown from the contact angle measurement that PU stamps surface has good affinity with acetonitrile,guaranteeing the well distribution of DNA monomers on patterned stamps. Laser confocal fluorescence microscopy images of oligonucleotide arrays after hybridization confirmed polyurethane is an excellent material for molecular stamps when ransferring polar chemicals and conducting rections on interfaces by stamping.     

Application of Pac Ester in Thioester Method for the Synthesis of Cyclopentapeptides

Thioester method for the synthesis of cyclopeptides is improved by using Pac (Pac = phenacyl, CH2COC6Hs) ester as a protecting group of 3-mercaptopropionic acid. The Pac group is easy to be removed from C-terminal with zinc in acetic acid. The protected glycine thioester and peptide thioesters synthesized by the improved method, are easy to be purified, so the final linear peptides are pure enough for the following cyclization. Furthermore, this method is flexible for peptide chain elongation,either from C-termlnal or from N.terminal. So it is an efficient and practical method for synthesis of bioactive peptides. Two N-protected pentapeptide thioesters, Boc-Pro-Tyr-Leu-Ala-GIySCH2CH2COOPac and Boc-Ala-Tyr-Leu-Ala-Gly-SCH2CH2COOPac were synthesized by the improved thloester method.After deprotecting Pac ester with zinc in aqueous acetic acid and Boc group with trifluoroacetic acid in CH2C12, two free pentapeptide tldoesters were obtained. Ag^ -assisted cyclization in acetate buffered solution afforded two cyclic pentapeptides c(Pro-Tyr-Leu-Ala-Gly) and c(Ala-Tyr-Leu-Ala-Gly).Effects of different buffer pH, different Ag^ concentrations, etc. on the cyclization were studied.     

An Efficient Method for the Synthesis of A 1,6-Anhydro-α-D-Galactofuranose Derivative and its Application in the Synthesis of Oligosaccharides

ABSTRACT

Synthesis of 1,6-anhydro-2,3,5-tri-O-benzoyl-β-D-galactofuranose (3) has been achieved in good yield by stannic chloride catalysed ring closure of methyl 2,3,4-tri-O-benzoyl-6-O-benzyl-β-D-galactofuranoside (1). The anhydro compound 3 was converted to the furanoside donors 6 and 7 with an easily removable O-6 acetyl group. The donors 6 and 7 were utilised for the synthesis of a di- and a trisaccharide containing β-D-galactofuranosides.     

Hydrothermal Synthesis of Metal Silicates

Organically templated metal phosphates have been extensively studied because of interesting structural chemistry and potential applications in catalysis. However, in most cases the organic templates cannot be removed without collapse of the frameworks. This is in contrast to the high thermal stability and extensive applications of zeolites in refinery and petrochemical processes. Therefore, studies have been directed to the synthesis of transition metal silicates to produce more stable framewo…     

Effect of pH on the Hydrothermal Synthesis of BN Nanocrystals

Boron nitride (BN) has been synthesized using hydrothermal synthesis method. The experimental results showed that the pH value of the reaction solution has an important effect on the yield and phases of BN samples. As the pH value decreased, the content of cBN increased and the yield improved. The increase in cBN content is resulted from the conversion of oBN into cBN under hydrothermal condition, and the growth of cBN nanocrystals may due to the decrease in the reaction speed, thus the crystalline perfection of BN improved when the pH value decreased.     

Application of [3 + 2]-Cycloaddition in the Synthesis of Valdecoxib

A large scale synthesis of valdecoxib 1 is described. Our work features potential application of [3 + 2]-dipolar cycloaddition involving enamine and in situ–generated nitrile oxide derivatives.     

Application of the PMC Protecting Group in the Efficient Synthesis of 4,4‐Disubstituted Piperidines

Abstract

An efficient synthesis of the 4,4‐disubstituted piperidine scaffold 1 was accomplished by treating the PMC N‐protected α,β‐unsaturated ethyl cyanoacetate 9 with various Grignard reagents (R₁MgX). Subsequent heating at 190°C in a strong base provided carboxylic acids 12–20b in good yield. The PMC group was easily removed at room temperature with 33% HBr in acetic acid.     

Multinuclear NMR study of lanthanide(Ⅲ)complexes of 1,2-PDTA in aqueous solution

The complexation oflanthanide(Ⅲ) cations with 1,2-propanediaminetetraacetate (1,2-PDTA)in aqueous solution has been investigated by ~(23)Na,~(35)Cl,~2H and ~(17)O NMR shift measurements.It hasbeen shown that the contact shifts are dominant for ~(17)O,~(35)Cl and ~2H (only for the heavier lanthanideseries) and the pseudocontact shifts are dominant for ~(23)Na.It is suggested that the 1,2-PDTA ligandis bound pentadentately via the two nitrogens and the three carboxylates for the lighter lanthanidecomplexes,hexdentately via the two nitrogens and the four carboxylates for the heavier ones.Thenumbers of the water coordinated were determined.The small amount of chloride anion in innercoordination sphere was observed.     

Polymer-supported 1,4-dihydronicotinamide: Synthesis and Application in the Reduction of the Activated Olefins

s: Three new polymer-supported NAD(P)H models (I, II, III) were designed and synthesized, which can efficiently reduce many activated olefins under mild conditions.1 The most advantageous feature of the three NAD(P)H models is (i) easy work-up and separation of the reaction products and (ii) good potential for recycle use of the NAD(P)H models, which makes the three new polymer-supported NAD(P)H models a promising alternative both in research laboratories and in industrial processes.…     

Application of CO_2-TPD in the Synthesis of Composite Oxides from Metal-Organic Precursors

Pyrolysisusingmetal-organicmoleculesasprecursorswasoneoftheextensivelyusedmethodsforthepreparationofhigh-qualitycompositeoxidesinrecentyears'.However,itwasfoundthatthepropertiesoffinalproductaregreatlyinfluencedbythefiringcondition.Duetothedifficultyincharacterization,informationabouttheprocessfromtheprecursortothecalcinedproduct,however,islack.Inthisletter,wereportthesuccessfulapplicationofCO,-TPDtechniqueintheinvestigationofphaseformationduringpyrolysis.CombinedwithlR,TG,DTAandXRDtechn…     

Synthesis of Iso-condensed Heteroaromatic Pyrroles and Their Application in the Preparation of Conducting Polymers

Iso-condensed heteroaromatic pyrroles 1 are 10π-electron aromatic compounds. They are of interest from both theoretical and synthetic points of view. They are the cyclic analogues of heteroaromatic ortho-quinodimethanes 2, and can react with dienophiles in a Diels-Alder reaction to give the synthetically useful cycloadducts 3. Many of them are also of potential pharmaceutical importance because they are isosteric with indoles. Iso-condensed heteroaromatic pyrroles 1 can be used also as the m…     

Hydrothermal in situ preparation of phthalocyanine–TiO2 nanocomposites for photocatalytic activity under visible light irradiation

Research on Chemical Intermediates - In this study, phthalocyanine (Pc)–TiO2 nanocomposites were prepared via in situ hydrothermal method. The metal-free, zinc(II), cobalt(II), nickel(II) and...     

Synthesis of a Polymer—bound Sensitizer and its Application in the Photoisomeriz

A polymer-bound photosensitizer was synthesized by the reaetion of Merritield resin with 9-anthraeenemethanol in the presence of potassium hydride.The photoisomerization of trans-vitamin D3 to cis-vitamin D3 was earried out with this polymer-bound photosensitizer in ethanol and toluene solutions.The experiment results demonstrate that this solid photosensitizer is efficient for the photoismerization and easy for separation from the reaetion mixtures.     

The Study of Cation Distributions in the Dehydrated KFI-Type Zeolites

1.introductionVanDun&Mortier[islededastatisticalthenn~cmthelndLi&theP]aPPliedaMOnteon0stmulatedannealinmethodl.J,qtOPedCtwellthe~boQfcationdistribuonsinFAUtwZeOliteSaCC0rdint0thebocpoStulallonsthatallthesitee~esfi's(ed,I',II,tysed'sD1fOrexchang~cationsiteSofboasite-tweds)andthepotenallenergywofint~onfrOmtheedonsattheadjacentsitedIandI'are~oftempetri.Later,Lievens&Mederl81winedarlyaPPliedthethenn~cmcht0theKFI-twedtes,Knde`Sivs.60lar,~h~sthePresent~rtoaPPlywintheMOnteonomethodto…     

Application of the Benzoyl O-Protecting Group in the Synthesis of α,β-Dehydrotyrosine-containing Amides and Imidazolones

Russian Journal of Organic Chemistry - The use of O-benzoyl protection in the synthesis of N-benzoyl-α,β-dehydrotyrosine benzylamide, and the corresponding 4-imidazolone was studied. The...     

Application of the Intramolecular α-Amido-alkylation Reaction for the Synthesis of Dibenzo /a,h/ Quinolizines

5,6,9-Trihydro-8H-dibenzo [a,h] quinolizin-8-ones 6 are obtained from adducts of 3,4-dihydroiso-quinolines 1 and phenylacetyl chlorides as a result of an intramolecular α-amidoalkylation reaction.     

The Preparation of α-Phosphonovinylzirconocenes and their Application in the Stereospecific Synthesis of α-Halo-l-alkenylphosphonates

Hydrozirconation of 1-alkylnylphosphonates gives the organozirconium(Ⅳ) complexes 2 in syn-addition way.Complexs 2 was trapped with NCS,NBS or I2 to afford stereodifined α-halo-1-alkenylphosphonates in moderate to high yields.     

A New Method for the Synthesis of Selenium Nanoparticles and the Application to Construction of H202 Biosensor

The well-distributed, stable selenium nanoparticles (10 nm) with good adhesive abilityand biocompatibility were successfully synthesized by using the template of chitosan cross-linkedwith glutaradehyde. The resulting selenium nanoparticles were used as a new carrier forhorseradish peroxidase to construct H2O2 biosensors with good performances.     

Synthesis of 1,3-Diols: Its Application to the Synthesis of α-Lipoic Acid

1,3-diols have been prepared from monosubstituted olefins, and the utility of this method in the synthesis of α-lipoic acid has been described.     

A Novel Substrate for in situ Synthesis of Oligonucleotides： Hydrolyzed Microporous Polyamide-6 Membrane

A novel substrate for in situ synthesis of oligonucleotide was prepared by hydrolyzing microporous polyamide-6 membranes in a 0.01mol/L NaOH/(H2O-CH3OH) mixture medium. The formation of amines (NH2) on the surface was proved by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). The treated membrane was applied for in situ synthesis of oligonucleotide and a single step coupling efficiency determined by ultraviolet (UV) spectra was above 98%.