Ring‐Opening Metathesis Polymerization Based Pore‐Size‐Selective Functionalization of Glycidyl Methacrylate Based Monolithic Media: Access to Size‐Stable Nanoparticles for Ligand‐Free Metal Catalysis

Monolithic polymeric supports have been prepared by electron‐beam‐triggered free‐radical polymerization using a mixture of glycidyl methacrylate and trimethylolpropane triacrylate in 2‐propanol, 1‐dodecanol, and toluene. Under appropriate conditions, phase separation occurred, which resulted in the formation of a porous monolithic matrix that was characterized by large (convective) pores in the 30 μm range as well as pores of <600 nm. The epoxy groups in pores of >7 nm were hydrolyzed by using poly(styrenesulfonic acid) (M_w=69 400 g mol^?1, PDI=2.4). The remaining epoxy groups inside pores of <7 nm were subjected to aminolysis with norborn‐5‐en‐2‐ylmethylamine ( 2 ) and provided covalently bound norborn‐2‐ene (NBE) groups inside these pores. These NBE groups were then treated with the first‐generation Grubbs initiator [RuCl₂(PCy₃)₂(CHPh)]. These immobilized Ru–alkylidenes were further used for the surface modification of the small pores by a grafting approach. A series of monomers, that is, 7‐oxanorborn‐5‐ene‐2,3‐dicarboxylic anhydride ( 3 ), norborn‐5‐ene‐2,3‐dicarboxylic anhydride ( 4 ), N,N‐di‐2‐pyridyl‐7‐oxanorborn‐5‐ene‐2‐carboxylic amide ( 5 ), N,N‐di‐2‐pyridylnorborn‐5‐ene‐2‐carboxamide ( 6 ), N‐[2‐(dimethylamino)ethyl]bicyclo[2.2.1]hept‐5‐ene‐2‐carboxamide ( 7 ), and dimethyl bicyclo[2.2.1]hept‐5‐en‐2‐ylphosphonate ( 8 ), were used for this purpose. Finally, monoliths functionalized with poly‐ 5 graft polymers were used to permanently immobilize Pd²⁺ and Pt⁴⁺, respectively, inside the pores. After reduction, metal nanoparticles 2 nm in diameter were formed. The palladium‐nanoparticle‐loaded monoliths were used in both Heck‐ and Suzuki‐type coupling reactions achieving turnover numbers of up to 167 000 and 63 000, respectively.     

Surface‐Functionalized,Ring‐Opening Metathesis Polymerization‐Derived Monoliths for Anion‐Exchange Chromatography

Ring‐opening metathesis polymerization (ROMP) was used for the synthesis of monolithic capillary columns with inner diameters of 200 µm. The resulting polymeric monoliths were characterized by inverse size‐exclusion chromatography (ISEC). Surface functionalization was carried out in situ using 2‐(N,N‐dimethylaminoethyl)norborn‐5‐ene‐2‐ylcarboxylic amide ( 1 ). The resulting functionalized monoliths were successfully used in anion‐exchange chromatography of oligodeoxynucleotides.

     

Functional Monolithic Materials for Boronate‐Affinity Chromatography via Schrock Catalyst‐Triggered Ring‐Opening Metathesis Polymerization

Monolithic polymeric materials are prepared via ring‐opening metathesis copolymerization of norborn‐2‐ene with 1,4,4a,5,8,8a‐hexahydro‐1,4,5,8‐exo,endo‐dimethanonaphthalene in the presence of macro‐ and microporogens, that is, of n‐hexane and 1,2‐dichloroethane, using the Schrock catalyst Mo(N‐2,6‐(2‐Pr)₂‐C₆H₃)(CHCMe₂Ph)(OCMe₃)₂. Functionalization of the monolithic materials is accomplished by either terminating the living metal alkylidenes with various functional aldehydes or by post‐synthesis grafting with norborn‐5‐en‐2‐ylmethyl‐4‐(4,4,5,5‐tetramethyl‐1,3,2‐dioxaborolan‐2‐yl)benzoate. Finally, boronate‐grafted monolithic columns (100 × 3 mm i.d.) are successfully applied to the affinity chromatographic separation of cis‐diol‐based biomolecules.     

One‐step strategy for the synthesis of a derivatized cyclodextrin‐based monolithic column

Derivatized β‐cyclodextrin (β‐CD) functionalized monolithic columns were prepared by a “one‐step” strategy using click chemistry. First, the intended derivatized β‐CD monomers were synthesized by a click reaction between propargyl methacrylate and mono‐6‐azido‐β‐CD and then sulfonation or methylation was carried out. Finally, monolithic columns were prepared through a one‐step in situ copolymerization of the derivatized β‐CD monomer and ethylene glycol dimethacrylate. The sulfated β‐CD‐based monolith was successfully applied to the hydrophilic interaction liquid chromatography separation of nucleosides and small peptides, while the methylated β‐CD‐functionalized monolith was useful for the separation of nonpolar compounds and drug enantiomers in capillary reversed‐phase liquid chromatography. The structures of the monomers were characterized by Fourier transform infrared spectroscopy and mass spectrometry. The physicochemical properties and column performance of monoliths were evaluated by scanning electron microscopy and micro high performance liquid chromatography. This strategy has considerable prospects for the preparation of other derivatized CD‐functionalized methacrylate monoliths.     

A facile and efficient one‐step strategy for the preparation of β‐cyclodextrin monoliths

A novel, facile, and efficient one‐step copolymerization strategy was developed for the preparation of β‐cyclodextrin (β‐CD) methacrylate monolithic columns using click chemistry. The novel mono‐(1H‐1,2,3‐triazol‐4‐ylmethyl)‐2‐methylacryl‐β‐CD monomer was synthesized by a click reaction between propargyl methacrylate and mono‐6‐azido‐β‐CD, and then monolithic columns were prepared through a one‐step in situ copolymerization of the mono‐(1H‐1,2,3‐triazol‐4‐ylmethyl)‐2‐methylacryl‐β‐CD monomer and ethylene dimethacrylate. The physicochemical properties and column performance of the fabricated monolithic columns were characterized by elemental analysis, SEM, and micro‐HPLC. Satisfactory column permeability, efficiency, and separation performance were obtained for the optimized poly(mono‐(1H‐1,2,3‐triazol‐4‐ylmethyl)‐2‐methylacryl‐β‐CD‐co‐ethylene dimethacrylate) monolithic columns. Additionally, typical hydrophilic interaction chromatography retention behavior was observed on the monoliths at high acetonitrile content in the mobile phase. Although the enantioselectivity of our monolithic columns did not meet the level of other reported β‐CD monolithic columns, this one‐step strategy based on click chemistry still provides an interesting and effective model as it offers the possibility to easily prepare related novel CD methacrylate monoliths through a one‐step copolymerization strategy.     

Effect of fabrication strategy on the enantioseparation performance of β‐cyclodextrin‐functionalized polymethacrylate monoliths: A comparative evaluation

To evaluate the effect of the preparation strategy on the enantioseparation performance of β‐cyclodextrin‐functionalized monoliths, a series of β‐cyclodextrin‐functionalized organic polymeric monolithic columns were prepared through two‐step, single‐step, and one‐pot approaches, using the same cyclodextrin, linker–spacer, and crosslinker. Physicochemical characterization of the columns was carried out by determining the morphology, β‐cyclodextrin density, permeability, and chromatographic efficiency. For each type of monolithic column, the enantioresolution of 22 chiral compounds, including mandelic acid derivatives, nonsteroidal anti‐inflammatory drugs, N‐derivatized amino acids, and herbicides, was comparatively studied under optimum chromatographic conditions. The β‐cyclodextrin‐functionalized monolithic columns prepared through the one‐pot approach exhibited higher enantioresolution for most chiral compounds, and they have the advantage of good controllability and simple preparation. On the other hand, the enantioresolution obtained on columns prepared through the single‐step approach was quite unsatisfactory, and therefore the effect of using different linking spacers and crosslinkers was studied. A significant improvement of enantioresolution for 2‐chloro‐mandelic acid was obtained by using N ,N‐methylenebisacrylamide instead of ethylene dimethacrylate as the crosslinker in the single‐step preparation.     

Helical Poly(α,β‐unsaturated ketone) with Bulky Pendant of Binaphthyl from Anionic Polymerization of ((−)‐Menthyl (S)‐6′‐Acrylyl‐2′‐methyloxy‐1,1′‐binaphthalene‐2‐carboxylate

((?)‐Menthyl (S)‐6′‐acrylyl‐2′‐methyloxy‐1,1′‐binaphthalene‐2‐carboxylate ( 3 ) was synthesized and anionically polymerized using n‐BuLi as an initiator in toluene. The monomer 3 was levorotatory and had an [α]_D²⁵ value of ?72.4, but its corresponding polymer poly‐ 3 was dextrorotatory and showed an [α]_D²⁵ value of +162.0. Poly‐ 3 was confirmed to exist in the form of one‐handed helical structure in solution by means of comparing the specific optical rotation and the CD spectra with that of 3 and the model compounds such as (?)‐menthyl (S)‐6′‐propionyl‐2′‐methyloxy‐1,1′‐binaphthalene‐2‐carboxylate 2b and (?)‐menthyl (S)‐6′‐heptanoyl‐2′‐methyloxy‐1,1′‐binaphthalene‐2‐carboxylate 2c . This conclusion was also confirmed by the fact that the g‐value of poly‐ 3 is about 11 times of that of monomer 3 .     

One‐pot preparation of mercaptotetrazole‐silica hybrid monoliths by the thiol‐ene click reaction for mixed‐mode capillary liquid chromatography

A novel mercaptotetrazole‐silica hybrid monolithic column was prepared for capillary liquid chromatography, in which the thiol‐end mercaptotetrazole was mixed with hydrolyzed γ‐methacryloxypropyltrimethoxysilane and tetramethyloxysilane for the co‐polycondensation and thiol‐ene click reaction in a one‐pot process. The effects of the molar ratio of silanes, the amount of mercaptotetrazole, and the volume of porogen on the morphology, permeability and pore properties of the as‐prepared mercaptotetrazole‐silica hybrid monoliths were investigated in detail. A series of test compounds including alkylbenzenes, amides and anilines were employed for evaluating the retention behaviors of the mercaptotetrazole‐silica hybrid monolithic columns. The results demonstrated that the mercaptotetrazole‐silica hybrid monoliths exhibited hydrophobic, hydrophilic as well as ion‐exchange interaction. The run‐to‐run, column‐to‐column and batch‐to‐batch reproducibilities of the mercaptotetrazole‐silica hybrid monoliths were satisfactory with the relative standard deviations less than 1.4 (n  = 5), 3.9 (n  = 3) and 4.0% (n  = 5), respectively. In addition, the mercaptotetrazole‐silica hybrid monolith was further applied to the separation of sulfonamides, nucleobases and protein tryptic digests. These successful applications confirmed the promising potential of the mercaptotetrazole‐silica hybrid monolith in the separation of complex samples.     

Polymer‐based monolithic column with incorporated chiral metal–organic framework for enantioseparation of methyl phenyl sulfoxide using nano‐liquid chromatography

A new approach to the preparation of enantioselective porous polymer monolithic columns with incorporated chiral metal–organic framework for nano‐liquid chromatography has been developed. While no enantioseparation was achieved with monolithic poly(4‐vinylpyridine‐co‐ethylene dimethacrylate) column, excellent separations of both enantiomers of (±)‐methyl phenyl sulfoxide were achieved with its counterpart prepared after admixing metal–organic framework [Zn₂(benzene dicarboxylate)(l‐lactic acid)(dmf)], which is synthesized from zinc nitrate, l ‐lactic acid, and benzene dicarboxylic acid in the polymerization mixture. These novel monolithic columns combined selectivity of the chiral framework with the excellent hydrodynamic properties of polymer monoliths, may provide a great impact on future studies in the field of chiral analysis by liquid chromatography.     

Helical polyacetylenes carrying 2,2,6,6‐tetramethyl‐1‐piperidinyloxy and 2,2,5,5‐tetramethyl‐1‐pyrrolidinyloxy moieties: Their synthesis,properties, and function

2,2,6,6‐Tetramethyl‐1‐piperidinyloxy (TEMPO)‐ and 2,2,5,5‐tetramethyl‐1‐pyrrolidinyloxy (PROXYL)‐containing (R)‐1‐methylpropargyl TEMPO‐4‐carboxylate ( 1 ), (R)‐1‐methylpropargyl PROXYL‐3‐carboxylate ( 2 ), (rac)‐1‐methylpropargyl PROXYL‐3‐carboxylate ( 3 ), (S)‐1‐propargylcarbamoylethyl TEMPO‐4‐carboxylate ( 4 ), and (S)‐1‐propargyloxycarbonylethyl TEMPO‐4‐carboxylate ( 5 ) (TEMPO, PROXYL) were polymerized to afford novel polymers containing the TEMPO and PROXYL radicals at high densities. Monomers 1–3 and 5 provided polymers with moderate number‐average molecular weights of 8200–140,900 in 49–97% yields in the presence of (nbd)Rh⁺[η⁶‐C₆H₅B^?(C₆H₅)₃], whereas 4 gave no polymer with this catalyst but gave polymers possessing low M_n (3800–7500) in 56–61% yield with [(nbd)RhCl]₂‐Et₃N. Poly( 1 ), poly( 2 ), and poly( 4 ) took a helical structure with predominantly one‐handed screw sense in THF and CHCl₃ as well as in film state. The helical structure of poly( 1 ) and poly( 2 ) was stable upon heating and addition of MeOH, whereas poly( 4 ) was responsive to heat and solvents. All of the free radical‐containing polymers displayed the reversible charge/discharge processes, whose capacities were in a range of 43.2–112 A h/kg. In particular, the capacities of poly( 2 )–poly( 5 )‐based cells reached about 90–100% of the theoretical values regardless of the secondary structure of the polymer, helix and random. Poly( 1 ), poly( 2 ), and poly( 4 ) taking a helical structure exhibited better capacity tolerance towards the increase of current density than nonhelical poly( 3 ) and poly( 5 ) did. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5431–5445, 2007     

Synthesis,one‐ and two‐photon properties of poly[9,10‐bis(3,4‐bis(2‐ethylhexyl‐oxy)phenyl)‐2,6‐anthracenevinylene‐alt‐N‐octyl‐3,6‐/2,7‐carbazolevinylene]

The synthesis, one‐ and two‐photon absorption (TPA) and emission properties of two novel 2,6‐anthracenevinylene‐based copolymers, poly[9,10‐bis(3,4‐bis(2‐ethylhexyloxy)phenyl)‐2,6‐anthracenevinylene‐alt‐N‐octyl‐3,6‐carbazolevinyl‐ene] ( P1 ) and poly[9,10‐bis(3,4‐bis(2‐ethylhexyloxy)phenyl)‐2,6‐anthracenevinyl‐ene‐alt‐N‐octyl‐2,7‐carbazolevinylene] ( P2 ) were reported. The as‐synthesized polymers have the number‐average molecular weights of 1.56 × 10⁴ for P1 and 1.85 × 10⁴ g mol^?1 for P2 and are readily soluble in common organic solvents. They emit strong bluish‐green one‐ and two‐photon excitation fluorescence in dilute toluene solution (? _P1 = 0.85, ? _P2 = 0.78, λ_em( P1 ) = 491 nm, λ_em( P2 ) = 483 nm). The maximal TPA cross‐sections of P1 and P2 measured by the two‐photon‐induced fluorescence method using femtosecond laser pulses in toluene are 840 and 490 GM per repeating unit, respectively, which are obviously larger than that (210 GM) of poly[9,10‐bis‐(3,4‐bis(2‐ethylhexyloxy) phenyl)‐2,6‐anthracenevinylene], indicating that the poly(2,6‐anthracenevinylene) derivatives with large TPA cross‐sections can be obtained by inserting electron‐donating moieties into the polymer backbone. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 463–470, 2010     

Selective single monomer addition in living cationic polymerization: Sequential double end‐functionalization in combination with capping agent

Amine‐functionalized and amine‐carboxylate double‐functionalized polymers ( I and II , respectively) have been synthesized by a selective single addition of a protected 2‐aminoethyl vinyl ether (BocVE) {CH₂ = CH[OCH₂CH₂N(Boc)₂]; Boc = t‐butoxycarbonyl} onto a living cationic poly(n‐butyl vinyl ether) [poly(NBVE)] initiated with the SnCl₄/n‐Bu₄NCl system: ( I ) ‐(NBVE)_n‐ CH₂CH(OCH₂CH₂NH₂)‐H; ( II ) ‐(NBVE)_n‐CH₂CH(OCH₂CH₂NH₂)‐CH₂CO₂H. The single addition was examined with a set of alkene monomers less reactive than NBVE, including BocVE, 2‐chloroethyl vinyl ether, 2‐vinyloxyethylphtalimide, and styrene (St). Upon addition of 10 molar excess of these alkenes onto the living ends, only BocVE led to the intended single adduct, and this was attributed to a chelating interaction of the two carboxylate groups in the terminal BocVE unit with the growing poly(NBVE) terminal, thus sterically hampering further propagation. A simple acid‐catalyzed Boc‐deprotection led to the amino‐functionalized version I . Alternatively, an additional quenching the BocVE‐capped living end (the precursor of I ) with sodium malonate, followed by double deprotection of the Boc and the malonate groups gave the double‐functionalized version II . The selective addition of a single monomer molecule is thus a new method for addressable or site‐specific introduction of functional groups along polymer chains. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3375–3381, 2010     

Fast fabrication of a hybrid monolithic column containing cyclic and aliphatic hydrophobic ligands via photo‐initiated thiol‐ene polymerization

Three monomers, octakis (3‐mercaptopropyl) octasilsesquioxane, 1,2,4‐trivinylcyclohexane and isophytol were employed to synthesize a novel monolithic stationary phase via photo‐initiated thiol‐ene click polymerization for reversed‐phase liquid chromatography. Several factors such as porogenic system, reaction time and the molar ratio of functional groups were investigated in detail. The resulting poly(POSS‐co‐TVCH‐co‐isophytol) monolithic column exhibited suitable permeability for fast separation and outstanding thermal stability. Five alkylbenzenes were employed to evaluate the ability of chromatographic separation of the resulting monolithic columns at different flow rates, and showed the highest column efficiencies of 90,200–93,100 N/m (corresponding to 10.4–10.6 μm of plate height) at a velocity of 0.41 mm/s. The baseline separations of five anilines and eight phenols further proved the applicability of poly(POSS‐co‐TVCH‐co‐isophytol) monolithic column in the separation of small molecules.     

In‐situ photopolymerized polyhedral oligomeric silsesquioxane‐derived monolithic capillary columns with quinidine functionality for enantioseparation by nano‐liquid chromatography

The successful fabrication of monolithic capillary columns for enantiomer separations was achieved within vinylized fused silica capillaries via fast “one‐pot” photo‐initiated free radical polymerization reaction. A mixture consisting of polyhedral oligomeric silsesquioxane, O‐[2‐(methacryloyloxy)ethylcarbamoyl]‐10,11‐dihydroquinidine was copolymerized in the presence of n‐butanol, ethylene glycol and photo‐initiator 2,2‐dimethoxy‐2‐phenylacetophenone. The morphology of the resultant polymeric hybrid inorganic‐organic material and its permeability as well as porosity can be controlled by adjusting the composition of the monomers and binary porogenic solvent. The chromatographic characteristics of the columns have been investigated. Separation factors of N‐acetyl‐phenylalanine (Ac‐Phe) and dichlorprop dropped with decrease of chiral functional monomer. Permeability was better when the macroporogen ethyleneglycol was present at higher concentrations during the polymerization. In general, the chiral compounds were well separated (dichlorprop: α = 1.53, R_s up to 4.14; Ac‐Phe: α = 1.36, R_s up to 2.69) by nano‐HPLC with an optimized enantioselective monolithic capillary column which can be prepared within a few minutes.     

Incorporation of metal‐organic framework amino‐modified MIL‐101 into glycidyl methacrylate monoliths for nano LC separation

Metal‐organic frameworks consisting of amino‐modified MIL‐101(M: Cr, Al, and Fe) crystals have been synthesized and subsequently incorporated to glycidyl methacrylate monoliths to develop novel stationary phases for nano‐liquid chromatography. Two incorporation approaches of these materials in monoliths were explored. The metal‐organic framework materials were firstly attached to the pore surface through reaction of epoxy groups present in the parent glycidyl methacrylate‐based monolith. Alternatively, NH₂‐MIL‐101(M) were admixed in the polymerization mixture. Using short time UV‐initiated polymerization, monolithic beds with homogenously dispersed metal‐organic frameworks were obtained. The chromatographic performance of embedded UV‐initiated composites was demonstrated with separations of polycyclic aromatic hydrocarbons and non‐steroidal anti‐inflammatory drugs as test solutes. In particular, the incorporation of the NH₂‐MIL‐101(Al) into the organic polymer monoliths led to an increase in the retention of all the analytes compared to the parent monolith. The hybrid monolithic columns also exhibited satisfactory run‐to‐run and column‐to‐column reproducibility.     

Comparative evaluation of a one‐pot strategy for the preparation of β‐cyclodextrin‐functionalized monoliths: Effect of the degree of amino substitution of β‐cyclodextrin on the column performance

To further evaluate the feasibility and applicability of the one‐pot strategy in monolithic column preparation, two novel β‐cyclodextrin‐functionalized organic polymeric monoliths were prepared using two β‐cyclodextrin derivatives, i.e. mono(6‐amino‐6‐deoxy)‐β‐cyclodextrin and heptakis(6‐amino‐6‐deoxy)‐β‐cyclodextrin. In this improved method, mono(6‐amino‐6‐deoxy)‐β‐cyclodextrin or heptakis(6‐amino‐6‐deoxy)‐β‐cyclodextrin reacted with glycidyl methacrylate to generate the corresponding functional monomers and were subsequently copolymerized with ethylene dimethacrylate. The polymerization conditions for both monoliths were carefully optimized to obtain satisfactory column performance with respect to column efficiency, reproducibility, permeability, and stability. The obtained poly(glycidyl methacrylate‐mono(6‐amino‐6‐deoxy)‐β‐cyclodextrin‐co‐ethylene dimethacrylate) and poly(glycidyl methacrylate‐heptakis(6‐amino‐6‐deoxy)‐β‐cyclodextrin‐co‐ethylene dimethacrylate) monoliths exhibited a uniform structure, good permeability, and mechanical stability as indicated by scanning electron microscopy and micro‐high‐performance liquid chromatography experimental results. Because of the probable existence of multi‐glycidyl methacrylate linking spacers on the poly(glycidyl methacrylate‐heptakis(6‐amino‐6‐deoxy)‐β‐cyclodextrin‐co‐ethylene dimethacrylate) monolith, the effect of the ratio of glycidyl methacrylate/heptakis(6‐amino‐6‐deoxy)‐β‐cyclodextrin was especially studied, and satisfactory reproducibility could still be achieved by strictly controlling the composition of the polymerization mixture. To investigate the effect of the degree of amino substitution of β‐cyclodextrin on column performance, a detailed comparison of the two monoliths was also carried out using series of analytes including small peptides and chiral acids. It was found that the β‐cyclodextrin‐functionalized monolith with mono‐glycidyl methacrylate linking spacers demonstrated better chiral separation performance than that with multi‐glycidyl methacrylate linking spacers.     

Relative Lectin Binding Properties of T‐Antigen‐Containing Glycopolymers: Copolymerization of N‐Acryloylated T‐Antigen Monomer vs. Graft Conjugation of Aminated T‐Antigen Ligands onto Poly(N‐acryloxysuccinimide)

Water‐soluble T‐antigen‐ (Galβ(1–3)‐GalNAcα) containing random glycopolymers were synthesized by two strategies: i) radical copolymerization of N‐acryloylated monomers with (NH₄)₂S₂O₈ and ii) graft conjugation of an end‐group‐aminated T‐antigen together with labeling reagent ( 16 ) by amidation onto poly(N‐acryloxysuccinimide) and its derivatives followed by quenching with NH₄OH. All glycoconjugates demonstrated antigenicity by double‐radial immunodiffusion assays with peanut lectin from Arachis hypogaea. The biocytin‐labeled terpolymer ( 23 ) also showed practical heterobifunctional antigenicity toward peanut lectin and streptavidin, giving the corresponding two precipitin bands in the assay.     

Synthesis and ring‐opening polymerizations of novel S‐glycooxazolines

A new 2‐oxazolines containing S‐galactosyl substituents linked to alkyl chains of different lengths; (S‐glycooxazoline) were prepared relatively in high yields. By using a 1:1 adduct of 2‐methyl‐2‐oxazoline and methyl triflate, as the initiator, the monomer was polymerized via ring‐opening polymerization (ROP) to give products with relatively narrow molecular weight distributions. Homo‐ and copolymerization were performed, and the kinetics of these new S‐glycooxazolines in the ROP are investigated. After a quantitative deprotection, poly(2‐oxazoline)s having pendant carbohydrate were obtained. The interaction of the poly(S‐glycooxazoline) with RCA₁₂₀ lectin was investigated, the binding constant between glycopolymer and lectin was increased by 10² times compared with that of the monosaccharide (D ‐galactose). The in vivo expression of green fluorescent protein using the synthesized poly(S‐glycooxazoline)s as polymeric inducers in Escherichia coli host were performed. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

One‐pot synthesis of star‐block copolymers using double click reactions

3‐Arm star‐block copolymers, (polystyrene‐b‐poly(methyl methacrylate))₃, (PS‐b‐PMMA)₃, and (polystyrene‐b‐poly(ethylene glycol))₃, (PS‐b‐PEG)₃, are prepared using double‐click reactions: Huisgen and Diels–Alder, with a one‐pot technique. PS and PMMA blocks with α‐anthracene‐ω‐azide‐ and α‐maleimide‐end‐groups, respectively, are achieved using suitable initiators in ATRP of styrene and MMA, respectively. However, PEG obtained from a commercial source is reacted with 3‐acetyl‐N‐(2‐hydroxyethyl)‐7‐oxabicyclo[2.2.1]hept‐5‐ene‐2‐carboxamide (7) to give furan‐protected maleimide‐end‐functionalized PEG. Finally, PS/PMMA and PS/PEG blocks are linked efficiently with trialkyne functional linking agent 1,1,1‐tris[4‐(2‐propynyloxy)phenyl]‐ethane 2 in the presence of CuBr/N,N,N′,N″,N″‐pentamethyldiethylenetriamine (PMDETA) at 120 °C for 48 h to give two samples of 3‐arm star‐block copolymers. The results of the peak splitting using a Gaussian deconvolution of the obtained GPC traces for (PS‐b‐PMMA)₃ and (PS‐b‐PEG)₃ displayed that the yields of target 3‐arm star‐block copolymers were found to be 88 and 82%, respectively. © Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7091–7100, 2008     

Quinolone Analogs 13: Synthesis of Novel 1,1′‐(2‐Methylenepropane‐1,3‐diyl)di(4‐quinolone‐3‐carboxylate) and Related Compounds

The reaction of the 4‐hydroxyquinoline‐3‐carboxylate 6 with pentaerythritol tribromide gave the 1,1′‐(2‐methylenepropane‐1,3‐diyl)di(4‐quinolone‐3‐carboxylate) 11 , whose reaction with bromine afforded the 1,1′‐(2‐bromo‐2‐bromomethylpropane‐1,3‐diyl)di(4‐quinolone‐3‐carboxylate) 12 . Compound 12 was transformed into the (Z)‐1,1′‐(2‐acetoxymethylpropene‐1,3‐diyl)di(4‐quinolone‐3‐carboxylate) 13 or (E)‐1,1′‐[2‐(imidazol‐1‐ylmethyl)propene‐1,3‐diyl]di(4‐quinolone‐3‐carboxylate) 14 . Hydrolysis of the dimer (Z)‐ 13 or (E)‐ 14 with potassium hydroxide provided the (E)‐1,1′‐(2‐hydroxymethylpropene‐1,3‐diyl)di(4‐quinolone‐3‐carboxylic acid) 15 or (Z)‐1,1′‐[2‐(imidazol‐1‐ylmethyl)propene‐1,3‐diyl]di(4‐quinolone‐3‐carboxylic acid) 16 , respectively. The nuclear Overhauser effect (NOE) spectral data supported that those hydrolysis resulted in the geometrical conversion of (Z)‐ 13 into (E)‐ 15 or (E)‐ 14 into (Z)‐ 16 .