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Mitochondria-targeted fluorescent organic nanoparticles (TYDLs) with a low detection limit (75 nM) were reported for the ratiometric detection of SO2/HSO3−in vitro and in vivo.

Two kinds of AIE-active fluorescent organic nanoparticles were designed and constructed as anti-counterfeiting photoresponsive materials. One is fluorescent organic nanoparticles (TPELs) based on a self-assembly strategy, which were self-assembled from novel amphiphilic tetraphenylethylene (TPE) molecules decorated with a lactose moiety and different photoresponsive tags. The other is polymeric fluorescent organic nanoparticles (F-TPEs) derived from the nanoprecipitation strategy, which utilized pluronic copolymer F127 to encapsulate hydrophobic TPEs without lactosyl modifications. Upon UV light irradiation, these AIE-active materials exhibit different photooxidation behaviors in an aqueous solution to give cyan, orange and green fluorescence emissions, and they were successfully used as an anti-counterfeiting fluorescent hydrogel and ink.

A dilactosyl-dicyanovinyl-functionalized tetraphenylethene (TPELC) was designed, synthesized and used for ratiometric sensing of cyanide. TPELC was comprised of three moieties (tetraphenylethylene, dicyanovinyl group and lactose unit) in one molecule, making TPELC water-soluble and aggregation-induced emission (AIE)-active and selectively reactive to cyanide. Compared with other reported fluorescent probes containing dicyanovinyl group, TPELC is the first AIE luminogen to be assembled as fluorescent organic nanoparticles (FONs) for sensing of cyanide in water without the use of surfactant or the help of organic solvents based on the nucleophilic addition reaction. The detection mechanism was verified by liquid chromatograph mass spectrometry experiments and by protonation of cyanide to reduce the nucleophilicity of cyanide. In addition, TPELC was used for detection of the cyanide content of food samples and test strips were developed to simplify the detection procedure.

Amyloid-related diseases, such as Alzheimer's disease, are all considered to be related to the deposition of amyloid fibrils in the body. Insulin is a protein hormone that easily undergoes aggregation and fibrillation to form more toxic amyloid-like fibrils. So far, it is still challenging to develop a new protocol to study the

Hypochlorous acid (HOCl) plays a crucial role in many physiological processes and is widely used as bleach, deodorant and fungicide. In this work, we designed an amphiphilic hydrazone fluorescent molecule THG-1 containing hydrophilic sugar units and hydrophobic tetraphenylethylene unit for ratiometric detection of HOCl with high sensitivity and excellent selectivity based on HOCl-triggered hydrolyzation reaction and aggregation-induced emission (AIE) effect. The detection mechanism was verified by liquid chromatograph mass spectrometry experiments and scanning electron microscope (SEM) tests. Contrast experiments revealed that the numbers of lactose unit and hydrazone linker were essential for assembly of THG-1 and detection of HOCl. In addition, THG-1 was successfully used for imaging of exogenous and endogenous HOCl in living cells.

Surfactants play important roles in chemical industries and have become well-known environmental pollutants owing to their extensive use in different fields. In this work, we reported a fluorescent probe, namely, BDP-Zn2+ for the discrimination of four kinds of surfactants and the determination of CMC values. BDP-Zn2+ was composed of covalently linked BODIPY, carbazole, N,N-bis(2-pyridylmethyl)ethylenediamine (BPEA) and zinc ions to fabricate a novel push-pull molecular structure. Upon the addition of surfactants, the probe exhibited a turn-on fluorescence response and the emission was enhanced on increasing the surfactant concentrations. This indicated that the fluorescence intensity and the ratios of the emission at 607 nm to that at 514 nm as fingerprints could be used to identify the CMC values of the surfactants. Our current work provides an alternative method to efficiently discriminate different surfactants for the further studies of their physical and chemical functions.

The synthesis of O-, C-, and N-glycoconjugates has continuously been an attractive research subject due to the growing biological importance of various glycoconjugates. In recent years, by careful changing the glycosylation reaction conditions, especially the amount of activators and the preactivation temperature, (p-Tol)2SO/Tf2O preactivition strategy was developed as a general method for the synthesis of various O-, C-, and N-glycoconjugates, including related biological active glycoconjugates, such as nucleosides and antigen Lewisa etc. High yields and excellent stereoselectivities were obtained even without the anchimeric assistance at the adjacent position of anomeric carbon. In this review, we predominantly make a review on the progress of the (p-Tol)2SO/Tf2O preactivition strategy from O-, C-sialylation to general O-, N-glycosylation.

Imaging-based total bacterial count and type identification of bacteria play crucial roles in clinical diagnostics, public health, biological and medical science, and environmental protection. Herein, we designed and synthesized a series of tetraphenylethenes (TPEs) functionalized with one or two aldehyde, carboxylic acid, and quaternary ammonium groups, which were successfully used as fluorescent materials for rapid and efficient staining of eight kinds of representative bacterial species, including pathogenic bacteria Vibrio cholera, Klebsiella pneumoniae, and Listeria monocytogenes and potential bioterrorism agent Yersinia pestis. By comparing the fluorescence intensity changes of the aggregation-induced-emission (AIE) materials before and after bacteria incubation, the sensing mechanisms (electrostatic versus hydrophobic interactions) were simply discussed. Moreover, the designed AIE materials were successfully used as an efficient artificial tongue for bacteria discrimination, and all of the bacteria tested were identified via linear discriminant analysis. Our current work provided a general method for simultaneous broad-spectrum bacterial imaging and species discrimination, which is helpful for bacteria surveillance in many fields.

Based on a preactivation strategy using ( p -Tol) 2 SO/Tf 2 O, a new O -fucosylation method with thioglycoside as donor under mild conditions was reported. High yields and excellent α-stereoselectivities of the fucosylation were obtained with secondary sugar alcohol as acceptors. Moreover, the novel fucosylation strategy was successfully applied to the synthesis of an important Lewis blood group antigen Lewis a , which was obtained in nine linear steps with 27% overall yield.

A novel fluorescent chemosensor HACBA with carbazole-hemicyanine fluorophore as signal reporter and N,N,N'-tri(2-pyridylmethyl)ethylenediamine (TPEA) as binding sites was designed and synthesized. Its assemblies with anionic surfactant sodium dodecyl sulfate (SDS) show improved fluorescence emission stability and enhanced fluorescence intensity. HACBA/SDS system can selectively recognize Cu2+, which led to a dramatic fluorescence quenching. The in situ resultant HACBA-Cu(II)/SDS ensemble functioned as a highly selective and sensitive sensor for H2S with a turn-on fluorescent response. Our results show that the “on-off-on” molecular switch occured through the reversible formation-dissociation reaction between HACBA-Cu(II) complex and HACBA/CuS in the SDS micellar solution, and at least 3 cycles of on-off-on switches were observed.

Two water-soluble carbohydrate-coated AIE-activate fluorescent organic nanoparticles TPE3G and TPE4G were designed and synthesized for the detection of heparin. Different from the reported strategy, we not only utilized the general detection mechanism of electrostatic interactions, but also introduced the concept of carbohydrate-carbohydrate interactions (CCIs) to enrich the detection mechanism of heparin. TPE3G can serve as an efficient "turn-on" probe with higher selectivity towards heparin than TPE4G. TEM studies revealed that the micro-aggregated TPE3G was encapsulated with the heparin chain to form a complex self-assemblied composite and emits strong fluorescence. It is believed that the results illustrated in this study provide a novel strategy based on CCls to design water-soluble and more efficient bio-probes for various biological and clinical applications.

In this work, we designed and synthesized an aggregation-induced emission (AIE)-active tetraphenylethene-decorated pseudo-trisialic acid (TPE3S) and validated its high affinity for Siglecs using microscale thermophoresis techniques. TPE3S was a unique binding-on fluorescent trivalent sialocluster which was successfully utilized for the visualization of Siglecs expressed on the surface of mammalian cells.

Water-soluble ratiometric AIE-active fluorescent organic nanoparticles 2OA-FON for the specific sensing of cysteine over other biothiols are reported. The obtained amphiphilic probe included olefin aldehyde as recognizing unit, tetraphenylethylene as fluorescence reporter and lactose moiety as a hydrophilic group. This work provides a general design strategy based on the introduction of a sugar moiety into a hydrophobic AIEgen to develop ratiometric water-soluble fluorescent organic nanoparticles.

Ginsenoside is a large family of triterpenoid saponins from Panax ginseng, which possesses various important biological functions. Due to the very similar structures of these complex glycoconjugates, it is crucial to develop a powerful analytic method to identify ginsenosides qualitatively or quantitatively. We herein report an eight-channel fluorescent sensor array as artificial tongue to achieve the discriminative sensing of ginsenosides. The fluorescent cross-responsive array was constructed by four boronlectins bearing flexible boronic acid moieties (FBAs) with multiple reactive sites and two linear poly(phenylene-ethynylene) (PPEs). An "on-off-on" response pattern was afforded on the basis of superquenching of fluorescent indicator PPEs and an analyte-induced allosteric indicator displacement (AID) process. Most importantly, it was found that the canonical distribution of ginsenoside data points analyzed by linear discriminant analysis (LDA) was highly correlated with the inherent molecular structures of the analytes, and the absence of overlaps among the five point groups reflected the effectiveness of the sensor array in the discrimination process. Almost all of the unknown ginsenoside samples at different concentrations were correctly identified on the basis of the established mathematical model. Our current work provided a general and constructive method to improve the quality assessment and control of ginseng and its extracts, which are useful and helpful for further discriminating other complex glycoconjugate families.

3-AminoBODIPY derivatives ( 5a – e ) were unexpectedly synthesized by the coupling of amines with 2-BODIPY-borates in the presence of copper(II) acetate Cu(OAc) 2 and tetramethylethylenediamine (TMEDA) in the air at room temperature. 5a (p K a = 9.18) was found to be a novel colorimetric and ratiometric fluorescent pH probe at alkaline pH ranges.

Recent investigations revealed the close relationship between H2S and HNO in biological systems. It is significant to develop an efficient fluorescent sensor to realize the discriminative sensing of HNO and H2S. Herein, we designed and synthesized a novel fluorescent sensor (CuHCD) with hemicyanine-carbazole as fluorophore and bipyridine-triazole-Cu2+complex as receptor, which enabled the selective recognition of HNO and H2S, respectively via the non-covalent modulation of surfactant assemblies. The CuHCD/surfactant sensor system exhibited excellent selectivity for H2S at 5 mM SDS in HEPES buffer, and displayed high specificity for HNO at 1 mM SDS in HEPES buffer over other common anions and reactive species. Different detection mechanisms in sensing H2S and HNO were deeply investigated. The results showed that H2S seized Cu2+ from the complex to recover the fluorescence of HCD, while HNO reduced Cu2+ to Cu+ in the complex to turn on the fluorescence. In different SDS micellar systems, HCD possessed different dispersity and binding capacity with Cu2+, which led to the selective detection of H2S and HNO, respectively. The hypothesis was further confirmed by replacing SDS micelles with liposome under the same conditions.

Four-channel fluorescence assay toward six monosaccharides was achieved by employing two novel pyrene-functionalized boronlectins with flexible diboronic acid as receptors. The effects of pH values and aging time on the sensor properties were thoroughly evaluated by UV-vis, fluorescence spectroscopy and dynamic light scattering. We find that the fluorescence relative ratios were highly correlated with analyte concentrations at μM level. The flexibility of the receptors was perceived as an indispensable factor to produce diverse fluorescence signals toward different monosaccharides. Most importantly, integration of four fluorescence channels derived from the two sensors enables an excellent discrimination for all tested monosaccharides at a certain concentration or a concentration range via linear discriminant analysis (LDA). It is proposed that the multiple flexible linkers in the boronlectins could increase their self-adaptive capacity for different analytes, and facilitate the formation of stable boronlectin-sugar aggregate assemblies. In addition, practical sensing of glucose in the simulative blood and urine was illustrated to be feasible in the presence of interferences at physiological concentrations.

We report a turn-on tetravalent sialic acid-coated tetraphenylethene luminogen (TPE4S) with excellent hydrophilicity, good stability, high sensitivity and unique selectivity towards sialidases, and the maximum fluorescence enhancement was ∼40 fold. More importantly, TPE4S was successfully utilized for the screening of sialidase inhibitors and diagnosis of bacterial vaginosis.

N,N-Di-2-picolylamine (DPA)-derived diboronic acid receptors (NHBAs) with a flexible linker were designed and synthesized in this study, and two-component sensing ensembles based on cationic NHBAs and an anionic fluorescent indicator 8-hydroxypyrene-1,3,6-trisulfonic acid trisodium salt (HPTS) were successfully developed for both monosaccharides and disaccharides sensing. The dibranched ortho-substituted receptor NHoBA exhibited unexpected selectivity towards lactose among five disaccharides used. The discrimination of five disaccharides and six monosaccharides was finally achieved by the integrated sensor array through linear discriminant analysis (LDA).

An iron-catalyzed enantioselective and diastereoselective intramolecular olefin aminochlorination reaction is reported (ee up to 92%, dr up to 15 : 1). In this reaction, a functionalized hydroxylamine and chloride ion are utilized as nitrogen and chlorine sources, respectively. This new method tolerates a range of synthetically valuable internal olefins that are all incompatible with existing asymmetric olefin aminochlorination methods.

Based on a preactivation strategy using the (p-Tol)2SO/Tf2O system, a series of nucleosides were synthesized by coupling various thioglycosides with pyrimidines and purines under mild conditions. High yields and excellent β-stereoselectivities were obtained with either armed or disarmed N-glycosylation donors by tuning the amount of (p-Tol)2SO additive.

During the past decades, the interaction between boronic acids-functionalized sensors and saccharides is of great interest in the frontier domain of the interdiscipline concerning both biology and chemistry. Various boronic acid-based sensing systems have been developed to detect saccharides and corresponding derivatives in vitro as well as in vivo, which embrace unimolecular sensors, two-component sensing ensembles, functional assemblies, and boronic acid-loaded nanomaterials or surfaces. New sensing strategies emerge in endlessly with excellent selectivity and sensitivity. In this review, several typical sensing systems were introduced and some promising examples were highlighted to enable the deep insight of saccharides sensing on the basis of boronic acids.

YhdE is a Maf (multicopy associated filamentation) proteins from Escherichia coli which exhibits pyrophosphatase activity towards selected nucleotides, although its catalytic mechanism remains unclear. Herein we used a novel fluorescence probe (4-isoACBA–Zn(II) complex) to characterize the enzymatic properties of YhdE and its mutant, establishing a new method for assaying pyrophosphatase catalytic function. Our results reveal for the first time that the new fluorescence sensor confers high sensitivity and specificity and pyrophosphate (PPi) is the direct catalytic product of YhdE. Crystal structures of a mutant in the active-site loop (YhdE_E33A) show conformational flexibility implicated in the catalytic mechanism of YhdE. ITC experiments and computational docking further reveal that Asp70 and substrate dTTP coordinate Mn2+. Quantum mechanics calculations indicate that YhdE hydrolysis appears to follow a stepwise pathway in which a water molecule first attacks the α-phosphorus atom in the substrate, followed by the release of PPi from the pentavalent intermediate.

A tailor-made ratiometric fluorescent probe for nucleoside polyphosphates was fabricated based on a pyrene-functionalized zinc(II)–BPEA complex. The significant difference in both the fluorescence and 1H NMR signals of the probe on addition of ATP, ADP and AMP enables efficient discrimination between ATP, ADP and AMP.

Two new 2-aminobenzamide structural isomers, 4-isoACOBA and 5-isoACOBA, as fluorescent probes for Cd2+ and Zn2+ were fabricated with carbazolone as fluorophore and N,N-bis(2-pyridylmethyl)ethylenediamine (BPEA) as chelator. With Cd2+/Zn2+ as input, the two probes are characteristic of the transformation from “off–on” to “on–off” molecular switch by interchanging the substitution position of the fluorophore from C-4 to C-5 at the benzene ring. 4-IsoACOBA is a Cd2+-specific turn-on fluorescent probe exhibiting good discrimination between Cd2+ and Zn2+ with FCd2+/FZn2+ = 2.48, while 5-isoACOBA is a Zn2+-specific turn-off probe with FCd2+/FZn2+ = 4.50. The binding behaviours of 4-isoACOBA–Cd(II) and 5-isoACOBA–Zn(II) were deeply investigated by UV and fluorescence titration, ESI-MS analysis, and DFT study. The results indicate that both the electron donating/withdrawing ability and the substituted position of the fluorophore have remarkable influences on the probe sensing properties and selectivity.

Two BODIPY-carbazole dye based fluorescent probes BCA and BCAS were designed, synthesized and encapsulated by liposomes to obtain fluorescent nanoparticles BCA-FNP and BCAS-FNP. The fluorescence imaging showed that BCA-FNP was membrane-permeable and capable of localizing lysosomes in living cells.

Two novel anion sensors, methyl 4-(5-(5-chloro-2-hydroxyphenyl)-1,3,4-oxadiazol-2-yl) benzoate (L1) and methyl 4-(5-(2-hydroxyphenyl)-1,3,4-oxadiazol-2-yl) benzoate (L2) were reported. Their spectroscopic and colorimetric properties in CH2Cl2/CH3CN (1:2, v/v) solution for F− sensing were investigated by naked-eye, UV–vis, and fluorescence measurements. Both molecules with coplanar structure possess adjacent phenolic hydroxyl and 1,3,4-oxadiazole units, resulting in a sufficiently strong intramolecular hydrogen bond to hinder the association of most anions, but not F−, with phenolic hydroxyl hydrogen. They displayed the same color changes from colorless to yellow but different optical shifts upon addition of F−.

A dialdehyde–diboronate-functionalized tetraphenylethene (TPE-DABF) was reported as a H2O2-specific AIE luminogen. TPE-DABF, bearing multiple reductive units (aldehyde, boronate and fructose) in one molecule, afforded an excellent H2O2 selectivity over other ROS in biological buffer, and can be used for sensitive detection of glucose under neutral conditions.

Sweet as sugar: Sialyl sulfoxide protected by N-acetyl-5-N,4-O-oxazolidinone was readily prepared, and its coupling to various sugar acceptors was investigated. When the reaction was promoted by Tf(2)O/(Tol)(2)SO, efficient and highly α-selective sialylation yielded α(2,6), α(2,3), and α(2,4) glycosidic linkages between sialic acid and glucose/glacotose.

In the past few years heat shock protein 90 (Hsp90) inhibitors have been reported to possess significant antitumor activity. We investigated, for the first time, the antitumor activity of a novel Hsp90 inhibitor 2-(4-acetyloxycyclohexylamino)-4-(3, 6, 6-trimethyl-4-oxo-4, 5, 6, 7-tetrahydro-1 H -indazol-1-yl)-benzamide (BJ-B11) and the molecular mechanism underlying the apoptosis it induces in human chronic myeloid leukemia K562 cells. The results revealed that BJ-B11 triggered growth inhibition in K562 cells and other malignant cell lines in vitro with only minor toxicity in a normal human cell line. BJ-B11 inhibited the proliferation of K562 cells in a concentration- and time-dependent manner, with IC 50 values of 1.1 ± 0.2 μM and 0.4 ± 0.1 μM after 48 and 72 h incubations respectively. This most likely results from cell cycle arrest at the G 0 /G 1 phase and the induction of apoptosis. In addition, BJ-B11 degraded the Hsp90 client proteins Bcr-Abl and Akt, induced activation of caspase-9 and caspase-3, and subsequent cleavage of PARP. The caspase signals may originate from mitochondrial dysfunction, which is supported by the finding of cytochrome c release. In addition, inactivation of the Akt signaling pathway may be involved in the process of BJ-B11-induced apoptosis. Taken together, our data provide a putative molecular mechanism for the anticancer effect of BJ-B11 on K562 cells, and suggest a potential application for BJ-B11 in chronic myeloid leukemia therapy.

An N-acetyl-5-N,4-O-oxazolidinone-protected p-toluene 2-thio-sialoside donor, promoted by Ph(2)SO/Tf(2)O/TTBPy, was thoroughly investigated in the coupling to various acceptors. The stereoselectivity of the sialylation was found to be dependent on the various reaction conditions, such as pre-activation time, reaction time, the amount of Ph(2)SO, and TTBPy. A detailed Ph(2)SO/Tf(2)O-promoted glycosylation mechanism was proposed, which contained three crucial reactive species: an oxacarbenium ion, C2-sialyloxosulfonium salts, and oxosulfonium supramers. Our research results indicate that it is possible to tune the stereoselectivity of the sialylation by carefully changing the reaction conditions. For instance, Ph(2)SO (2.0-3.0 equiv)/TTBPy (0-1.0 equiv) promotion gives higher α-selective sialylation in dichloromethane, while Ph(2)SO (4-5 equiv)/TTBPy (0 equiv) or Ph(2)SO (2.0 equiv)/TTBPy (2.0 equiv) affords lower stereoselectivity.

Four novel Zn2+ fluorescent sensors have been designed with N,N-bis(2-pyridylmethyl)ethylenediamine as chelator and 2-aminobenzamide as fluorophore. These sensors were prepared in two or three steps from readily available starting materials. Of the four designed sensors, ZnABA was found to be the most efficient Zn2+-specific fluorescent probe and has good solubility in biological buffer, a large Stokes shift (186 nm), a high off–on fluorescence response (16-fold enhancement), and distinct selectivity towards Zn2+ over other metal ions. Our results have demonstrated an excellent linear relationship between the fluorescence intensity of ZnABA and the Zn2+ concentration from 0 to 10 μM, which indicates that ZnABA has the potential to be used for the quantitative determination of Zn2+ in an aqueous environment.

A sensitive and specific reversed-phase high-performance liquid chromatography method with ultraviolet detection has been developed and validated for the identification and quantification of SNX-2112 in rat plasma. Following sample preparation using liquid-liquid extraction, the analytes were separated by the mobile phase acetonitrile-water (40:60, v/v) with an Agilent RP-HPLC column (ZORBAX SB-C18, 5 microm, 4.6 mm x 250 mm) at a flow rate of 1 ml/min, column temperature of 30 degrees C and detection wavelength of 251 nm. The retention time of SNX-2112 was 11.2 min. A good linear relationship was obtained in the concentration range studied (0.07-21 microg/ml, R(2)0.9982), and the LLOD and LLOQ for SNX-2112 were 0.02 and 0.07 microg/ml, respectively. The mean absolute recovery of SNX-2112 in plasma ranged from 88.58 to 99.61% at the studied concentrations. The intra- and inter-batch relative standard deviations were 1.7-3.5 and 1.9-4.4%, respectively. This method was successfully applied to pharmacokinetic studies in rats after intravenous administration of SNX-2112.

Anionic conjugated polymer (PFP-SO 3 ) was assembled with a novel enzymatic substrate 6-O-modified PNP-,B-galactoside (1) for sensitive multiplex enzyme detections. The PFP-SO 3 - /1/ lipase/β-galactosidase system has two chemical input signals which are Input 1 (lipase) and Input 2 (β-galactosidase), and output optical signals such as fluorescence emission at 416 nm or 450 nm. Four types of logic gates, including YES, INH, NAND and AND, were successfully constructed and utilized for multiplex detections of lipase and β-galactosidase in one tube.

Ganglioside GM3 [α-Neu5Ac-(2,3)-β-Gal-(1,4)-β-Glc-(1,1)-Cer; 1] is considered as an important tumor-associated carbohydrate antigen, which can be used in the development of tumor vaccine. In this study, a facile and convergent synthetic strategy for GM3 was developed, and the preparation of three building blocks started from the most readily available compounds sialic acid, lactose, and L-serine. Ceramide aglycon 9 was constructed from L-serine in 13 steps with 6 % overall yield, and lactosyl trichloroacetimidate 14 was synthesized from lactose in 7 steps with 25 % yield. With novel N-acetyl-5-N,4-O-oxazolidinone protected p-toluenethiosialoside 15 as donor, which was developed by our group, the sialylation of benzoyl-protected lactosyl ceramide diol 23 was successfully accomplished in 54 % yield. Our strategy here provides a shorter linear total synthesis of GM3 in five steps and with 26 % overall yield. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

A novel N-acetyl-5-N,4-O-oxazolidinone-protected p-toluenethiosialoside was readily prepared from sialic acid andp-toluenethiol. It was demonstrated that the p-toluenethiosialoside could be successfully applied to the α-selective sialylations with various glycosyl acceptors in good yields. In the coupling of N-acetyl-5-N,4-O-oxazolidinone-protected p-toluenethiosialoside and gluco alcohol, a quantitative reaction yield and high α-selectivity were obtained in dichloromethane-acetonitrile (2:1) at -40 °C.

The activity of enzymes to form a peptide bond in organic solvent was greatly influenced by observed pH and water content. The precursors of two sweeteners, P-Asp-Xaa-OR (P = Z or For, Xaa-OR = Phe-OMe or Ala-OcHex), were synthesized by enzyme, and the reaction conditions were studied systematically. Z-Asp-OH was coupled with H-Phe-OMe or H-Ala-OcHex by thermolysin in tert-amyl alcohol. The best coupling results were obtained when the optimized observed pH was 8 or 9, and the water content was about 6% (V/V). The protecting group Z is better than For under the reaction conditions and H-Phe-OMe is a better nucleophile than H-Ala-OcHex. The expected optically pure peptides were obtained when the racemic amino acids were used as amino components in the starting materials. The physical constants of P-Asp-Xaa-OR synthesized by thermolysin are identical with those of peptides synthesized by chemical method.

α-Chymotrypsin catalyzed peptide bond formation was studied in ionic liquids using the synthesis of a protected fragment of Leu-enkephalin, ZTyrGlyGlyOEt, as model reaction. MOEMIM·PF 6 was found to be the most favorable solvent among the six different 1-alkyl-3-methylimidazolium hexafluorophosphates and tetrafluoroborates ionic liquids screened. With MOEMIM·PF 6 as reaction media, several di- or tripeptide derivatives were successfully prepared in 68–75% isolated yields.

Based on a preactivation strategy using the (p-Tol)2SO/Tf2O system, a series of nucleosides are synthesized by coupling various thioglycosides such as (I), (IV), and (VII) with pyrimidine and purine bases.

A sugar epitope, α-(2,9)-trisialic acid, was synthesized and labeled by cyanine dyes through Cu(I)-catalyzed azide–alkyne cycloaddition (CuAAC). The cyanine tagged oligosialic acid can be utilized as an efficient fluorescent probe to image the glycan-binding receptors on PC-12 cells. The distribution of Sia-binding immunoglobulin-like lectins (Siglecs) for α-(2,9)-trisialic acid was visualized by Cy3/Cy5 or FRET channel fluorescence imaging.

A series of N -protected amino acid-estradiol derivative conjugates have been synthesized by coupling of 17β-aminoestra-1,3,5 (10)-trien-3-ol ( 1 ) or 17β-hydrazonoestra-1,3,5 (10)-trien-3-ol ( 2 ) with different amino acids via the catalysis of subtilisin Carlsberg in organic solvent. Various factors, including the structure of amino acid residue, different N -protecting groups of amino acids, different esters of carboxyl group and water content of the reaction media that influence the efficiency of enzymatic reactions were systematically studied. In vitro biological activity studies revealed that the binding interactions between estradiol derivative conjugates and estrogen receptor can be affected by the properties of the conjugated amino acid, but the effects of the change in binding properties did not result in changes in biological activities in both MCF-7 and HeLa cell lines.