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The enhancement of reactivity inside supramolecular coordination cages has many analogies to the mode of action of enzymes, and continues to inspire the design of new catalysts for a range of reactions. However, despite being a near-ubiquitous class of reactions in organic chemistry, enhancement of the reduction of carbonyls to their corresponding alcohols remains very much underexplored in supramolecular coordination cages. Herein, we show that encapsulation of small aromatic aldehydes inside a supramolecular coordination cage allows the reduction of these aldehydes with the mild reducing agent sodium cyanoborohydride to proceed with high selectivity (ketones and esters are not reduced) and in good yields. In the absence of the cage, low pH conditions are essential for any appreciable conversion of the aldehydes to the alcohols. In contrast, the specific microenvironment inside the cage allows this reaction to proceed in bulk solution that is pH-neutral, or even basic. We propose that the cage acts to stabilise the protonated oxocarbenium ion reaction intermediates (enhancing aldehyde reactivity) whilst simultaneously favouring the encapsulation and reduction of smaller aldehydes (which fit more easily inside the cage). Such dual action (enhancement of reactivity and size-selectivity) is reminiscent of the mode of operation of natural enzymes and highlights the tremendous promise of cage architectures as selective catalysts., Herein, we use a supramolecular coordination cage as a catalyst for the reduction of aldehydes to the corresponding alcohols using a weak hydride donor in neutral water, with a mode of action reminiscent of natural enzymes.

In this work, we compare labeling by two negatively charged fluorescent labels, 8-aminopyrene-1,3,6-trisulfonic acid (APTS) and 8-(2-hydrazino-2-oxoethoxy)pyrene-1,3,6-trisulfonic acid (Cascade Blue hydrazide [CBH]). Effectiveness of the labeling chemistries were investigated by 4-hydroxybenzaldehyde and maltoheptaose followed by LC/UV-MS and CE/LIF analysis, respectively. The reaction yield of APTS labeling was determined to be only ∼10%. This is due to reduction of almost 90% of the analyte by sodium cyanoborohydride to alcohol, which cannot be further labeled via reductive amination. However, the CBH labeling provides ∼90% reaction yield based on the LC/UV-MS measurements. The significantly higher labeling yield was also confirmed by CE/LIF measurements. Finally, the more effective hydrazone formation technique of CBH was characterized and applied for N-linked glycan analysis by CE/LIF.

Reductive amination coupling an aldehyde-containing polysaccharide, generated by periodate oxidation, with the amino groups in protein has been widely used in the synthesis of glycoconjugate vaccines. The conjugation is often achieved under slightly basic conditions via a Schiff’s base intermediate followed by its reduction with sodium cyanoborohydride. We observed that oxidized capsular polysaccharides such as Streptococcus pneumoniae type 6B (Pn-6B) and Haemophilus influenzae type a (HiA) underwent significant degradation during the conjugation in slightly basic media leading to sub-optimal glycoconjugates. Further study on oxidized Pn-3, Pn-6A, Pn-6C, Pn-2 polysaccharides and dextran provided evidence that the degradation is a result of base-catalysed β-elimination. In contrast to HiA, Pn-2, Pn-3, Pn-6B polysaccharides and dextran, oxidized Pn-6A and Pn-6C polysaccharides were stable under basic conditions due to lack of the leaving group at the β-position of the aldehyde. By performing conjugation of oxidized polysaccharides to bovine serum albumin (BSA) in phosphate buffer at pH 6.0, 6.8, 7.2 and 8.0, we concluded that the reductive amination proceeds best in slightly acidic media, particularly with those β-elimination susceptible polysaccharides.

Humans are exposed to large numbers of electrophiles from their diet, the environment, and endogenous physiological processes. Adducts formed at the N-terminal valine of hemoglobin are often used as biomarkers of human exposure to electrophilic compounds. We previously reported the formation of hemoglobin N-terminal valine adducts (added mass, 106.042 Da) in the blood of human smokers and nonsmokers and identified their structure as 4-hydroxybenzyl-Val. In the present work, mass spectrometry-based proteomics was utilized to identify additional sites for 4-hydroxybenzyl adduct formation at internal nucleophilic amino acid side chains within hemoglobin. Hemoglobin isolated from human blood was treated with para-quinone methide (para-QM) followed by global nanoLC-MS/MS and targeted nanoLC-MS/MS to identify amino acid residues containing the 4-hydroxybenzyl modification. Our experiments revealed the formation of 4-hydroxybenzyl adducts at the αHis20, αTyr24, αTyr42, αHis45, βSer72, βThr84, βThr87, βSer89, βHis92, βCys93, βCys112, βThr123, and βHis143 residues (in addition to N-terminal valine) through characteristic MS/MS spectra. These amino acid side chains had variable reactivity toward para-QM with αHis45, αTyr42, βCys93, βHis92, and βSer72 forming the largest numbers of adducts upon exposure to para-QM. Two additional mechanisms for formation of 4-hydroxybenzyl adducts in humans were investigated: exposure to 4-hydroxybenzaldehyde (4-HBA) followed by reduction and UV-mediated reactions of hemoglobin with tyrosine. Exposure of hemoglobin to a 5-fold molar excess of 4-HBA followed by reduction with sodium cyanoborohydride produced 4-hydroxybenzyl adducts at several amino acid side chains of which αHis20, αTyr24, αTyr42, αHis45, βSer44, βThr84, and βHis92 were verified in targeted mass spectrometry experiments. Similarly, exposure of human blood to ultraviolet radiation produced 4-hydroxybenzyl adducts at αHis20, αTyr24, αTyr42, αHis45, βSer44, βThr84, and βSer89. Overall, our results reveal that 4-hydroxybenzyl adducts form at multiple nucleophilic sites of hemoglobin and that para-QM is the most likely source of these adducts in humans.

Cross-linked enzyme aggregate (CLEA) methodology has been applied to immobilize cytochrome P450 BM3 variants (F87A and 21B3) with peroxygenase activity. Several Ru(II)-diimine complexes were found to be suitable cross-linking agents, surpassing the traditional glutaraldehyde and dextran aldehyde. They offer modular numbers of aldehyde functionalities and a more rigid framework than their organic counterparts. The F87A CLEAs display significant activity loss compared to the protein in solution. Meanwhile, for the 21B3 CLEAs, high activity recovery (up to 95%) is obtained. In order to minimize enzyme leaching from the CLEA, sodium cyanoborohydride was used to reduce the CLEAs imine bonds. The reduced CLEAs were active for several rounds of reactions leading to an overall increase in protein activity of 170% compared to the free protein in solution.

A method for the reductive difluoroalkylation of electron-deficient alkenes using 1,1-difluorinated iodides mediated by irradiation with blue light is described. The reaction involves radical addition of 1,1-difluorinated radicals at the double bond followed by hydrogen atom transfer from sodium cyanoborohydride.

Quantitative peptidomics and proteomics often use chemical tags to covalently modify peptides with reagents that differ in the number of stable isotopes, allowing for quantitation of the relative peptide levels in the original sample based on the peak height of each isotopic form. Different chemical reagents have been used as tags for quantitative peptidomics and proteomics, and all have strengths and weaknesses. One of the simplest approaches uses formaldehyde and sodium cyanoborohydride to methylate amines, converting primary and secondary amines into tertiary amines. Up to five different isotopic forms can be generated, depending on the isotopic forms of formaldehyde and cyanoborohydride reagents, allowing for five-plex quantitation. However, the mass difference between each of these forms is only 1 Da per methyl group incorporated into the peptide, and for many peptides there is substantial overlap from the natural abundance of 13C and other isotopes. In this study, we calculated the contribution from the natural isotopes for 26 native peptides and derived equations to correct the peak intensities. These equations were applied to data from a study using human embryonic kidney HEK293T cells in which five replicates were treated with 100 nM vinblastine for 3 h and compared with five replicates of cells treated with control medium. The correction equations brought the replicates to the expected 1:1 ratios and revealed significant decreases in levels of 21 peptides upon vinblastine treatment. These equations enable accurate quantitation of small changes in peptide levels using the reductive methylation labeling approach.

The cofactor tetrahydrofolate (THF) is used to reduce, oxidize, and transfer one-carbon (1C) units required for the synthesis of nucleotides, glycine, and methionine. Measurement of intracellular THF species is complicated by their chemical instability, signal dilution caused by variable polyglutamation, and the potential for interconversion among these species. Here, we describe a method using negative mode liquid chromatography-mass spectrometry (LC-MS) to measure intracellular folate species from mammalian cells. Application of this method with isotope-labeled substrates revealed abiotic interconversion of THF and methylene-THF, which renders their separate quantitation particularly challenging. Chemical reduction of methylene-THF using deuterated sodium cyanoborohydride traps methylene-THF, which is unstable, as deuterated 5-methyl-THF, which is stable. Together with proper sample handling and LC-MS, this enables effective measurements of five active folate pools (THF, 5-methyl-THF, methylene-THF, methenyl-THF/10-formyl-THF, and 5-formyl-THF) representing the biologically important 1C oxidation states of THF in mammalian cells. Graphical abstract Chemical derivatization with deuterated cyanoborohydride traps unstable methylene-THF as isotope-labeled 5-methyl-THF, enabling accurate quantification by LC-MS.

Kanosamine is an antibiotic and antifungal monosaccharide. The kanosamine biosynthetic pathway from glucose 6-phosphate in Bacillus cereus UW85 was recently reported, and the functions of each of the three enzymes in the pathway, KabA, KabB and KabC, were demonstrated. KabA, a member of a subclass of the VIβ family of PLP-dependent aminotransferases, catalyzes the second step in the pathway, generating kanosamine 6-phosphate (K6P) using l-glutamate as the amino-donor. KabA catalysis was shown to be extremely efficient, with a second-order rate constant with respect to K6P transamination of over 107 M-1s-1. Here we report the high-resolution structure of KabA in both the PLP- and PMP-bound forms. In addition, co-crystallization with K6P allowed the structure of KabA in complex with the covalent PLP-K6P adduct to be solved. Co-crystallization or soaking with glutamate or 2-oxoglutarate did not result in crystals with either substrate/product. Reduction of the PLP-KabA complex with sodium cyanoborohydride gave an inactivated enzyme, and crystals of the reduced KabA were soaked with the l-glutamate analog glutarate to mimic the KabA-PLP-l-glutamate complex. Together these four structures give a complete picture of how the active site of KabA recognizes substrates for each half-reaction. The KabA structure is discussed in the context of homologous aminotransferases.

A general stereoselective approach to previously unknown 1,2,4-triazepane-3-thiones/ones based on reduction or reductive alkylation of readily available 2,4,5,6-tetrahydro-3H-1,2,4-triazepine- 3-thiones/ones has been developed. The approach involved treatment of tetrahydrotriazepines with sodium cyanoborohydride in MeOH at pH 3 or with sodium borohydride and excess of carboxylic acid in tetrahydrofuran to give 1-unsubstituted or 1-alkyl-substituted 1,2,4-triazepane-3- thiones/ones, respectively. The latter were also prepared by reaction of 1-unsubstituted 1,2,4- triazepane-3-thiones/ones with sodium cyanoborohydride and aldehyde in MeOH in the presence of AcOH.

A chitosan/alginate dialdehyde multilayered film was fabricated using the layer-by-layer assembly method. Besides electrostatic interaction that promotes alternate adsorption of the oppositely charged polyelectrolytes, the Schiff base reaction between the amine groups on chitosan and the aldehyde groups on alginate dialdehyde provides a covalently cross-linked film, which after reduction by sodium cyanoborohydride is stable under both acidic and alkaline conditions. Moreover, the cross-linked film is responsive to changes in pH and addition of multivalent salts. The structural properties of the multilayered film such as thickness, refractive index, and water content were examined using simultaneous quartz crystal microbalance with dissipation monitoring and spectroscopic ellipsometry.

A general stereoselective approach to previously unknown 1,2,4-triazepane-3-thiones/ones based on reduction or reductive alkylation of readily available 2,4,5,6-tetrahydro-3H-1,2,4-triazepine-3-thiones/ones has been developed. The approach involved the treatment of tetrahydrotriazepines with sodium cyanoborohydride in MeOH at pH 3 or with sodium borohydride and excess of carboxylic acid in THF to give 1-unsubstituted or 1-alkyl-substituted 1,2,4-triazepane-3-thiones/ones, respectively. The latter were also prepared by the reaction of 1-unsubstituted 1,2,4-triazepane-3-thiones/ones with sodium cyanoborohydride and an aldehyde in MeOH in the presence of AcOH. The stereochemistry of the triazepane-3-thiones/ones obtained was established in DMSO solution and in the solid state using NMR spectroscopy and single-crystal X-ray diffraction. These data and DFT B3LYP/6-311++G(d,p) calculations show that the gauche effect plays a significant role in stabilization of preferred conformations of 1-unsubstituted 1,2,4-triazepane-3-thiones/ones.

In this report, we described a sensitive method for quantifying plant cell wall monosaccharides using chemical derivatization, reversed-phase high performance liquid chromatography separation with ultraviolet detection (HPLC-UV). Monosaccharides were derivatized with 2-aminobenzamide (2-AB) by reductive amination to increase the hydrophobicity and detected by ultraviolet absorption for HPLC-UV analysis. A non-toxic reductant, 2-picoline borane was utilized to replace the traditionally used sodium cyanoborohydride (NaCNBH3) to avoid the formation of toxic by-products. Experimental conditions were optimized using glucose as a model system to achieve a high reaction yield of 99%. Under the optimized conditions, we demonstrated that the derivatization yields of several saccharides with 2-AB using 2-picoline borane were all slightly higher than those observed using NaCNBH3. In plants, cell wall monosaccharides consist of arabinose, fucose, galactose, galacturonic acid, glucose, glucuronic acid, mannose, rhamnose, and xylose. Using our method, we successfully quantified these monosaccharides from Arabidopsis cell wall by HPLC-UV, and we obtained a good linearity at a wide dynamic range over five orders (1pmol through 10nmol of injection amount), a detection limit of ∼0.1pmole, and a high precision and accuracy.

Active polysaccharides isolated from various fungal sources have been implicated to stimulate immune response against various pathogens as well as self anomalies such as cancer. Therefore, the nuanced approach presented in our work was to blend polysaccharides derived from Pleurotus ostreatus with biocompatible ferrite nanoparticles and thereafter investigate the enhanced immune functionality of the polysaccharide-nanoparticle composite. A Schiff base reductive amination reaction occurred between the aldehyde group of the polysaccharide and the amine group of the nanoparticles in the presence of a strong reducing agent such as sodium cyanoborohydride to form a stable amide bond between the two conjugating molecules. The multifaceted conjugate was characterized by physiochemical techniques such as electron microscopy, FTIR, VSM and DLS measurements. This particulate form of the polysaccharide showed a marked escalation in the production of free radicals such as reactive oxygen and nitrogen species in murine macrophages as compared to the soluble form. Animal based experiments demonstrated a reduction in tumor volume and augmentation in the proliferation of splenocytes in particulate or conjugated polysaccharide treated mice. Furthermore, molecular signaling studies showed a high upregulation in p-p38 and p-MEK molecules in particulate polysaccharide treated RAW264.7 cells suggesting a cellular downstream mechanistic regulation behind the immunostimulative response.

One of the most frequently used high-resolution glycan analysis methods in the biopharmaceutical and biomedical fields is capillary electrophoresis with laser-induced fluorescence (CE-LIF) detection. Glycans are usually labeled by reductive amination with a charged fluorophore containing a primary amine, which reacts with the aldehyde group at the reducing end of the glycan structures. In this reaction, first a Schiff base is formed that is reduced to form a stable conjugate by a hydrogenation reagent, such as sodium cyanoborohydride. In large scale biopharmaceutical applications, such as clone selection for glycoprotein therapeutics, hundreds of reactions are accomplished simultaneously, so the HCN generated in the process poses a safety concern. To alleviate this issue, here we propose catalytic hydrogen transfer from formic acid catalyzed by water-soluble iridium(III)- and ruthenium(II)-phosphine complexes as a novel alternative to hydrogenation. The easily synthesized water-soluble iridium(III) and the ruthenium(II) hydrido complexes showed high catalytic activity in carbohydrate labeling. This procedure is environmentally friendly and reduces the health risks for the industry. Using carbohydrate standards, oligosaccharides released from glycoproteins with highly sialylated (fetuin), high mannose (ribonuclease B) and mixed sialo and neutral (human plasma) N-glycans, we demonstrated similar labeling efficiencies for iridium(III) dihydride to that of the conventionally used sodium cyanoborohydride based reaction. The derivatization reaction time was less than 20 min with no bias towards the above mentioned specific glycan structures.

Tin-free Giese reactions, employing primary, secondary, and tertiary alkyl iodides as radical precursors, ethyl acrylate as a radical trap, and sodium cyanoborohydride as a radical mediator, were examined in a continuous flow system. With the use of an automated flow microreactor, flow reaction conditions for the Giese reaction were quickly optimized, and it was found that a reaction temperature of 70 °C in combination with a residence time of 10–15 minutes gave good yields of the desired addition products.

WOS: 000321423600010 Pseudomonas sp. lipase was immobilized onto glutaraldehyde-activated Florisil (R) support via Schiff base formation and stabilized by reducing Schiff base with sodium cyanoborohydride. The immobilization performance was evaluated in terms of bound protein per gram of support (%) and recovered activity (%). A 4-factor and 3-level Box-Behnken design was applied for the acylation of (+/-)-2-(propylamino)-1-phenylethanol, a model substrate, with vinyl acetate and the asymmetric acylations of other (+/-)-2-amino-1-phenylethanols with different alkyl substituents onto nitrogen atom such as (+/-)-2-(methylamino)-1-phenylethanol, (+/-)-2-(ethylamino)-1-phenylethanol, (+/-)-2-(butylamino)-1-phenylethanol and (+/-)-2-(hexylamino)-1-phenylethanol were performed under the optimized conditions. The optimal conditions were bulk water content of 1.8%, reaction temperature of 51.5 degrees C, initial molar ratio of vinyl acetate to amino alcohol of 1.92, and immobilized lipase loading of 47 mg mL(-1). (R)-enantiomers of tested amino alcohols were preferentially acylated and the reaction purely took place on the hydroxyl group of 2-amino-1-phenylethanols. The increase of alkyl chain length substituted onto nitrogen atom caused an increase in the acylation yield and ee values of (S)-enantiomers. Enantiomeric ratio values were >200 for all the reactions. Our results demonstrate that the immobilized lipase is a promising biocatalyst for the preparation of (S)-2-amino-1-phenylethanols and their corresponding (R)-esters via O-selective acylation of (+/-)-2-amino-1-phenylethanols with vinyl acetate. (C) 2013 Elsevier Ltd. All rights reserved. Cukurova UniversityCukurova University [FEF 2005D15] This study was financially supported by Cukurova University with the project number of FEF 2005D15.

A series of novel 4-(3-(4-benzylpiperazin-1-yl)propoxy)-7-methoxy-3-substituted phenyl-2H-chromen-2-one (7a–7j) were synthesized by the reductive amination of 7-methoxy-3-phenyl-4-(3-piperizin-1-yl-propaxy)chromen-2-one (6) with different substituted aromatic aldehydes by using sodium cyanoborohydride in methanol. The newly synthesized compounds were purified and their structures were characterized by IR, 1H NMR, 13C NMR, and mass spectroscopy. The representative analogs were screened for in vitro antimicrobial activity. The compounds exhibited significant antibacterial and antifungal activity as that of standards. The data was further compared with structure-based investigations using docking studies with the crystal structure of oxidoreductase (1XDQ and 3QLS) protein organisms. The estimated score by genetic algorithm was found to have a good correlation with the experimental inhibitory potency of the derivatives.

Hydrazone derivatives exhibit a wide range of biological activities, while pyrazolo[3,4-b]quinoline derivatives, on the other hand, exhibit both antimicrobial and antiviral activity, so that all new derivatives in these chemical classes are potentially of value. Dry grinding of a mixture of 2-chloroquinoline-3-carbaldehyde and 4-methylphenylhydrazinium chloride gives (E)-1-[(2-chloroquinolin-3-yl)methylidene]-2-(4-methylphenyl)hydrazine, C17H14ClN3, (I), while the same regents in methanol in the presence of sodium cyanoborohydride give 1-(4-methylphenyl)-4,9-dihydro-1H-pyrazolo[3,4-b]quinoline, C17H15N3, (II). The reactions between phenylhydrazinium chloride and either 2-chloroquinoline-3-carbaldehyde or 2-chloro-6-methylquinoline-3-carbaldehyde give, respectively, 1-phenyl-1H-pyrazolo[3,4-b]quinoline, C16H11N3, (III), which crystallizes in the space groupPbcnas a nonmerohedral twin havingZ′ = 3, or 6-methyl-1-phenyl-1H-pyrazolo[3,4-b]quinoline, C17H13N3, (IV), which crystallizes in the space groupR\overline{3}. The molecules of compound (I) are linked into sheets by a combination of N—H...N and C—H...π(arene) hydrogen bonds, and the molecules of compound (II) are linked by a combination of N—H...N and C—H...π(arene) hydrogen bonds to form a chain of rings. In the structure of compound (III), one of the three independent molecules forms chains generated by C—H...π(arene) hydrogen bonds, with a second type of molecule linked to the chains by a second C—H...π(arene) hydrogen bond and the third type of molecule linked to the chain by multiple π–π stacking interactions. A single C—H...π(arene) hydrogen bond links the molecules of compound (IV) into cyclic centrosymmetric hexamers having \overline{3} (S6) symmetry, which are themselves linked into a three-dimensional array by π–π stacking interactions.

A thermally induced intramolecular 1,3-dipolar cycloaddition of an azidoester and subsequent sodium cyanoborohydride reduction of the resulting bicyclic vinylogous urethane to give a bicyclic aminolactone allows access to an eight carbon homologue of α-homomannojirimycin which is a weak fucosidase inhibitor. Intermediates with both an α- and β-amino acid moiety are described and may be useful for incorporation of homopipecolic acids into novel peptide libraries.

A novel synthetic approach towards α-trifluoromethyl-phenethylamines was elaborated by reduction of the electron deficient β-aryl-α-trifluoromethyl enamines and imines with sodium cyanoborohydride in the presence of trifluoroacetic acid. The starting imines were prepared by the reaction of primary amines with β-aryl-α-trifluoromethyl enamines or β-chloro-β-(trifluoromethyl)styrenes.

Abacavir is a nucleoside reverse transcriptase inhibitor marketed since 1999 for the treatment of infection with the human immunodeficiency virus type 1 (HIV). Despite its clinical efficacy, abacavir administration has been associated with serious and sometimes fatal toxic events. Abacavir has been reported to undergo bioactivation in vitro, yielding reactive species that bind covalently to human serum albumin, but the haptenation mechanism and its significance to the toxic events induced by this anti-HIV drug have yet to be elucidated. Abacavir is extensively metabolized in the liver, resulting in inactive glucuronide and carboxylate metabolites. The metabolism of abacavir to the carboxylate involves a two-step oxidation via an unconjugated aldehyde, which under dehydrogenase activity isomerizes to a conjugated aldehyde. Concurrently with metabolic oxidation, the two putative aldehyde metabolites may be trapped by nucleophilic side groups in proteins yielding covalent adducts, which can be at the onset of the toxic events associated with abacavir. To gain insight into the role of aldehyde metabolites in abacavir-induced toxicity and with the ultimate goal of preparing reliable and fully characterized prospective biomarkers of exposure to the drug, we synthesized the two putative abacavir aldehyde metabolites and investigated their reaction with the α-amino group of valine. The resulting adducts were subsequently stabilized by reduction with sodium cyanoborohydride and derivatized with phenyl isothiocyanate, leading in both instances to the formation of the same phenylthiohydantoin, which was fully characterized by NMR and MS. These results suggest that the unconjugated aldehyde, initially formed in vivo, rapidly isomerizes to the thermodynamically more stable conjugated aldehyde, which is the electrophilic intermediate mainly involved in reaction with bionucleophiles. Moreover, we demonstrated that the reaction of the conjugated aldehyde with nitrogen bionucleophiles occurs exclusively via Schiff base formation, whereas soft sulfur nucleophiles react by Michael-type 1,4-addition to the α,β-unsaturated system. The synthetic phenylthiohydantoin adduct was subsequently used as standard for LC-ESI-MS monitoring of N-terminal valine adduct formation, upon modification of human hemoglobin in vitro with the conjugated abacavir aldehyde, followed by reduction and Edman degradation. The same postmodification strategy was applied to investigate the products formed by incubation of abacavir with rat liver cytosol, followed by trapping with ethyl valinate. In both instances, the major adduct detected corresponded to the synthetic phenylthiohydantoin standard. These results suggest that abacavir metabolism to the carboxylate(s) via aldehyde intermediate(s) could be a factor in the toxic events elicited by abacavir administration. Furthermore, the availability of a reliable and fully characterized synthetic standard of the abacavir adduct with the N-terminal valine of hemoglobin and its easy detection in the model hemoglobin modifications support the usefulness of this adduct as a prospective biomarker of abacavir toxicity in humans.

In the presence of silica gel or titanium tetrachloride, ketene silyl acetals or ketene silyl thioacetals underwent 1,4-addition with alpha,beta unsaturated aldimines which possess a large triphenylmethyl group at the imino nitrogens followed by reduction with sodium cyanoborohydride to give aminopropylated products, delta-amino esters, in good yields. (C) 2011 Elsevier Ltd. All rights reserved.

2-Deoxyglucose (2-DG), an analog of glucose, is widely used to interfere with glycolysis in tumor cells and studied as a therapeutic approach in clinical trials. To evaluate the pharmacokinetics of 2-DG, we describe the development and validation of a sensitive HPLC fluorescent method for the quantitation of 2-DG in plasma. Plasma samples were deproteinized with methanol and the supernatant was dried at 45°C. The residues were dissolved in methanolic sodium acetate–boric acid solution. 2-DG and other monosaccharides were derivatized to 2-aminobenzoic acid derivatives in a single step in the presence of sodium cyanoborohydride at 80°C for 45 min. The analytes were separated on a YMC ODS C18 reversed-phase column using gradient elution. The excitation and emission wavelengths were set at 360 and 425 nm. The 2-DG calibration curves were linear over the range of 0.63–300 µg/mL with a limit of detection of 0.5 µg/mL. The assay provided satisfactory intra-day and inter-day precision with RSD less than 9.8%, and the accuracy ranged from 86.8 to 110.0%. The HPLC method is reproducible and suitable for the quantitation of 2-DG in plasma. The method was successfully applied to characterize the pharmacokinetics profile of 2-DG in patients with advanced solid tumors. Copyright © 2011 John Wiley & Sons, Ltd.

A mild procedure for the direct reaction of aromatic and aliphatic aldehyde bisulfite adducts with primary and secondary amine hydrochlorides in the presence of sodium cyanoborohydride in methanol is reported.

Analysis of N-glycans is often performed by LC coupled to fluorescence detection. The N-glycans are usually labeled by reductive amination with a fluorophore containing a primary amine to allow fluorescence detection. Moreover, many of the commonly applied labels also allow improved mass spectrometric detection of oligosaccharides. For reductive amination, the amine group of the label reacts with the reducing-end aldehyde group of the oligosaccharide to form a Schiff base, which is reduced to a secondary amine. Here, we propose the use of 2-picoline-borane as the reducing agent, as a non-toxic alternative to the extensively used, but toxic sodium cyanoborohydride. Using dextran oligosaccharides and plasma N-glycans, we demonstrate similar labeling efficacies for 2-picoline-borane and sodium cyanoborohydride. Therefore, 2-picoline-borane is a non-toxic alternative to sodium cyanoborohydride for the labeling of oligosaccharides.

The N-dicyclopropylmethyl (Dcpm) residue, introduced into amino acids via reaction of dicyclopropylmethanimine hydrochloride with an amino acid ester followed by sodium cyanoborohydride or triacetoxyborohydride reduction, can be used as an amide bond protectant for peptide synthesis. Examples which demonstrate the amelioration of aggregation effects include syntheses of the alanine decapeptide and the prion peptide (106-126). Avoidance of cyclization to the aminosuccinimide followed substitution of Fmoc-(Dcpm)Gly-OH for Fmoc-Gly-OH in the assembly of sequences containing the sensitive Asp-Gly unit.

The reduction of easily available methyl 5,6-dihydro-4H-1,2-oxazin-3-ylacetates provides an efficient route to different diastereomerically pure unnatural β-amino acids. A two-step protocol including reduction of the C=N bond of the initial oxazine with sodium cyanoborohydride during the first step and hydrogenation of the N-O bond during the second step produced the target β-amino acid esters with higher stereoselectivity than obtained with conventional catalytic hydrogenation.

Two procedures of glycated peptides' synthesis have been developed. The first method involves reductive alkylation of the epsilon-amino groups of lysine with 2,3:4,5-di-O-isopropylidene-beta-D-arabino-hexos-2-ulo-2,6-pyranose in the presence of sodium cyanoborohydride on solid support. The second one uses a new fully protected lysine derivative, which is a building block designed for direct introduction of the glycated lysine moiety into a peptide, according to the standard solid phase synthesis protocol. The applicability of the proposed methods for the synthesis of peptide-derived Amadori products is discussed. The structure of the synthesized glycated peptides was confirmed by high-resolution mass spectrometry and enzymatic hydrolysis. Circular dichroism studies, performed in water solution, revealed that the formation of the Amadori rearrangement product in the lysine side chain does not influence significantly the conformational preferences of the peptides studied. However, when the solvent was changed to trifluoroethanol, the glycated peptides preferred beta-turn conformation.

The oxidative modification of proteins is believed to play a critical role in the etiology and/or progression of several diseases. alpha-Aminoadipic semialdehyde (AAS) and gamma-glutamic semialdehyde (GGS) residues represent major oxidized amino acids generated in oxidized proteins. This paper describes a novel procedure for the specific and sensitive determination of AAS and GGS after their reductive amination with sodium cyanoborohydride and p-aminobenzoic acid, a fluorescence reagent, to their corresponding derivatives, followed by a high-performance liquid chromatography (HPLC) analysis. This fluorescent labeling of protein-associated aldehyde moieties is a simple and accurate technique that may be widely used to reveal increased levels of oxidatively modified proteins with reactive oxygen species during aging and disease.

Primary amino groups on the model peptide Xaa-Ala-Pro-Lys(ClZ)-Tyr(2BrZ), synthesized on a p-methylbenzhydryl amine resin with conventional Boc/benzyl protective group strategy, were reacted with 4,4'-dimethoxydityl chloride in dichloromethane, resulting in the introduction of the dimethoxydityl group, which is an acid-labile N-alkyl type of protective group. The secondary amino groups thereby formed can be methylated by treating the peptide-resin with formaldehyde and sodium cyanoborohydride in N,N-dimethylformamide. After the removal of the dimethoxydityl group with trifluoroacetic acid, the resulting N-methylated amino acid residues with a free secondary amino groups are accessible for acylation with the next activated Boc amino acid. With this method majority of the 20 common amino acids can be monomethylated directly on the resin and, in most cases, with very low levels of the side reactions. In the cases where the complete methylation is difficult to achieve, the remaining primary amino groups can be selectively acylated in the presence of secondary amino groups with trimethylacetic acid 1-hydroxybenzotriazole ester. The method provides a convenient general route to synthesize N-methylated derivatives of most of the occurring and synthetic amino acids.

C-Terminal peptide aldehydes and hydroxamates comprise two separate classes of effective inhibitors of a number of serine, aspartate, cysteine, and metalloproteases. Presented here is a method for preparation of both classes of peptide derivatives from the same resin-bound Weinreb amide precursor. Thus, 5-[(2 or 4)-formyl-3,5-dimethoxyphenoxy]butyramido-polyethylene glycol-polystyrene (BAL-PEG-PS) was treated with methoxylamine hydrochloride in the presence of sodium cyanoborohydride to provide a resin-bound methoxylamine, which was efficiently acylated by different Fmoc-amino acids upon bromo-tris-pyrrolidone-phosphonium hexafluorophosphate (PyBrOP) activation. Solid-phase chain elongation gave backbone amide-linked (BAL) peptide Weinreb amides, which were cleaved either by trifluoroacetic acid (TFA) in the presence of scavengers to provide the corresponding peptide hydroxamates, or by lithium aluminum hydride in tetrahydrofuran (THF) to provide the corresponding C-terminal peptide aldehydes. With several model sequences, peptide hydroxamates were obtained in crude yields of 68-83% and initial purities of at least 85%, whereas peptide aldehydes were obtained in crude yields of 16-53% and initial purities in the range of 30-40%. Under the LiAlH4 cleavage conditions used, those model peptides containing t-Bu-protected aspartate residues underwent partial side chain reduction to the corresponding homoserine-containing peptides. Similar results were obtained when working with high-load aminomethyl-polystyrene, suggesting that this chemistry will be generally applicable to a range of supporting materials.

Xylose, xylo-oligosaccharides with a degree of polymerization (DP) from 2 to 6, xylo-oligosaccharides carrying a single arabinofuranosyl, glucosyluronic acid, or 4- O -methyl glucosyluronic acid residues and 4-β- d -Xyl p -(1 → 4)- d -Xyl p -(1 → 3)-α- l -Rha p -(1 → 2)-α- d -Gal p A-(1 → 4)- d -Xyl p were labeled at their reducing ends with 2-aminobenzamide (2AB) in the presence of sodium cyanoborohydride (NaBH 3 CN). These derivatives were then analyzed by high-performance anion-exchange chromatography (HPAEC) and structurally characterized by electrospray-ionization mass spectrometry (ESI-MS) and by 1 H and 13 C NMR spectroscopy. Reacting Xyl 3 -Xylitol-2AB with UDP-Xyl in the presence of rice microsomes resulted in the formation of small amounts of Xyl 4–6 -Xylitol-2AB showing that the 2AB-labeled compound is an acceptor for xylosyltransferase. The 2AB-labeled xylo-oligosaccharides and the 2AB-labeled xylo-oligosaccharides carrying 4- O -methyl glucuronic acid are fragmented by xylanase and α-glucuronidase present in the culture filtrate of Fomitopsis palustris FFPRI 0507. Thus, the 2AB-labeled xylo-oligosaccharides are useful for studying enzymes involved in xylan degradation and biosynthesis.

Selective N -arylation of chitosan was performed via a Schiff bases formed by the reaction between the 2-amino group of glucosamine residue of chitosan with an aromatic aldehyde under acidic condition followed by reduction of the Schiff base intermediate with sodium cyanoborohydride (Borch reduction). Aromatic aldehydes bearing either an electron donating or electron withdrawing substituent were used. The chemical structures and thermal properties of the N -aryl chitosans were characterized by FT-IR, 1 H NMR, 13 C NMR, TGA, and DSC. The extent of N -substitution (ES) was influenced by the molar ratio of the aldehyde to the glucosamine residue of chitosan, the reaction time and the substituent on the aromatic ring. Lower ESs resulted from N -arylation using an aldehyde with an electron donating substituent. A linear relationship between the targeted ES and the ES obtained was observed when aldehydes bearing electron withdrawing substituents were employed.

A tandem reductive amination-SNAr reaction has been developed for the synthesis of 6-nitro-1,2,3,4-tetrahydroquinolines. Treatment of 4-(2-fluoro-5-nitrophenyl)-2-butanone or 3-(2-fluoro-5-nitrophenyl)-propanal with primary amines and sodium cyanoborohydride in methanol at room temperature provided good to excellent yields of the substituted tetrahydroquinolines. The reaction proceeded best with the ketone substrate using primary amines that were unbranched at the α-carbon. The aldehyde also produced the target heterocycles, but these were accompanied by 10-15% of the uncyclized side chain reductive amination products.

N-Arylated chitosans were synthesized via Schiff bases formed by the reaction between the primary amino group of chitosan with aromatic aldehydes followed by reduction of the Schiff base intermediates with sodium cyanoborohydride. Treatment of chitosan containing N,N-dimethylaminobenzyl and N-pyridylmethyl substituents with iodomethane under basic conditions led to quaternized N-(4-N,N-dimethylaminobenzyl) chitosan and quaternized N-(4-pyridylmethyl) chitosan. Methylation occurred at either N,N-dimethylaminobenzyl and N-pyridylmethyl groups before the residual primary amino groups of chitosan GlcN units were substituted. The total degree of quaternization of each chitosan varied depending on the extent of N-substitution (ES) and the sodium hydroxide concentration used in methylation. Increasing ES increased the total degree of quaternization but reduced attack at the GlcN units. N,N-dimethylation and N-methylation at the primary amino group of chitosan decreased at higher ES’s. Higher total degrees of quaternization and degrees of O-methylation resulted when higher concentrations of sodium hydroxide were used. The molecular weight of chitosan before and after methylation was determined by gel permeation chromatography under mild acidic condition. The methylation of the N,N-dimethylaminobenzyl derivative with iodomethane was accompanied by numerous backbone cleavages and a concomitant reduction in the molecular weight of the methylated product was observed. The antibacterial activity of water-soluble methylated chitosan derivatives was determined using Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) bacteria; minimum inhibitory concentrations (MIC) of these derivatives ranged from 32 to 128 μg/mL. The presence of the N,N-dimethylaminobenzyl and N-pyridylmethyl substituents on chitosan backbone after methylation did not enhance the antibacterial activity against S. aureus. However, N-(4-N,N-dimethylaminobenzyl) chitosan with degree of quaternization at the aromatic substituent and the primary amino group of chitosan of 17% and 16–30%, respectively, exhibited a slightly increased antibacterial activity against E. coli.

Two methods for the synthesis of N-(2-chloroethyl)glycine and-DL-alanine esters are proposed: 1) reductive amination of the C=O group of glyoxilic or pyruvic acids upon treatment with 2-chloroethylamine and sodium cyanoborohydride in methanol and 2) alkylation of 2-chloroethylamine with α-haloalkanoic acid esters in K2CO3-MeCN two-phase system.

β-Amylase was coupled to a periodate oxidized dextran by reductive alkylation in the presence of sodium cyanoborohydride. The loss of activity (57%) during the cross-linking of the enzyme was the result of steric hindrance near the catalytic site. In order to verify this hypothesis, the residual activity was determined with substrates of variable molecular size. The residual activity was inversely proportional to the particulate size of the substrate. Increases in residual activity, of up to 53% were obtained using an orientated chemical modification in the presence of a substrate which protects the catalytic site. Native and dextran-conjugated β-amylase were immobilized on an amino activated silica by a classical method using glutaraldehyde for the native enzyme and by reductive alkylation for the modified enzyme. The relative activity of the enzymes obtained after this insolubilization was very high for the modified amylase, 45% for a medium enzyme concentration, compared with 4% at the same concentration for the native enzyme. This difference can be attributed to the variation of the length of the space arm between the silica and the enzyme. The soluble β-amylase dextran conjugate had a superior thermoresistance to that of the native enzyme; its optimal temperature of activity was 5°C higher than that of the native enzyme. This stabilization may be attributable to a rigidification of the protein structure. Immobilization of both native and modified enzymes on a amino silica resulted in thermostabilization of the enzymes. The optimal temperature of activity was 70°C for the native immobilized β-amylase (some 10°C higher than that of the native enzyme) and 75°C for the chemically modified, and subsequently immobilized, β-amylase. The immobilized forms of the enzymes were used for 14 days at 55°C in continuous substrate processing. The greater eflciency of the chemically modified β-amylase was demonstrated by a four-fold increase in maltose production compared to the classical method of immobilization. A kinetic study confirmed the stabilization of the β-amylase by a reduction of the rate constant of inactivation of the different modified enzymes.

The cyclization of gamma-chloroamine 11, derived from l-alanine, and acetylenic sulfone 12 afforded the dehydropiperidine 19 via conjugate addition followed by intramolecular alkylation of the corresponding sulfone-stabilized anion. An unexpected acid-catalyzed desulfonylation of 19 occurred in one step via desilylation and tautomerization of the enamine moiety to the corresponding aldehyde, followed by elimination of p-toluenesulfinic acid. The highly stereoselective reduction of the resulting unsaturated aldehyde 25 with sodium cyanoborohydride produced piperidine 23 with a diastereomeric ratio of >98:2. (-)-(ent)-Julifloridine (8) was obtained by Swern oxidation of 23, followed by Wittig olefination and hydrogenation/debenzylation.

We report the divergent effects of a 3a-methyl and 3a-phenyl substituent on the chemoselectivity and stereoselectivity of reduction of the enamide moiety of N -Boc-hexahydro-1 H -indolin-5(6 H )-ones. Under ionic reduction conditions (triethylsilane/trifluoroacetic acid) the enamide group of 3a-methyl- N -Boc-hexahydro-1 H -indolin-5(6 H )-one was reduced to afford exclusively a cis ring-fused product. For the 3a-phenyl substituted analogue more forcing conditions (sodium cyanoborohydride at pH 2–2.5) were required and resulted in the selective reduction of the enamide group to give a trans ring-fused product as well as reduction of the ketone group.

The synthesis of tryptophan analogs is reported in which the conformation has been constrained by formation of a seven-membered lactam. Boc-protected 2′-formyl tryptophan was obtained by SeO2 oxidation of Boc-tetrahydro-β-carboline-3-carboxylic acid. Reductive amination was performed with a variety of amines and amino acid esters using sodium cyanoborohydride, followed by ring closure to the target compounds. The constrained Trp derivative has been incorporated into the endomorphin-1 opioid peptide sequence to probe the bioactive conformation.

An amine chemistry method was developed for the extraction of N-glycopeptides using amine-functionalized beads for glycoproteomics analysis. Two reductive amination reactions between primary amine and aldehyde were employed in this approach. The first one was to block the primary amines in the peptides by addition of formaldehyde and sodium cyanoborohydride into the peptide sample, and the second one was to couple the glycopeptides onto solid phase beads by incubating the glycopeptides containing aldehyde groups (oxidized by periodate) with the amine-functionalized beads in the presence of sodium cyanoborohydride. It was demonstrated that the blocking of primary amines in the peptides by the first reductive amination reaction prior to the periodate oxidation made the amine chemistry method very efficient and sensitive. This new method was validated by analysis of glycoprotein standards as well as proteome samples. It was found that this new method led to significant increase in the identification of N-glycosites compared with the conventional hydrazide chemistry method.

The use of a highly efficient reductive amination procedure for the postsynthetic end-capping of metal-templated helicate and tetrahedral supramolecular structures bearing terminal aldehyde groups is reported. Metal template formation of a [Fe2L3](4+) dinuclear helicate and two [Fe4L6](8+) tetrahedra (where L is a linear ligand incorporating two bipyridine domains separated by one or two 1,4-(2,5-dimethoxyaryl) linkers and terminated by salicylaldehyde functions is described. Postassembly reaction of each of these "open" di- and tetranuclear species with excess ammonium acetate (as a source of ammonia) and sodium cyanoborohydride results in a remarkable reaction sequence whereby the three aldehyde groups terminating each end of the helicate, or each of the four vertices of the respective tetrahedra, react with ammonia then undergo successive reductive amination to yield corresponding fully tertiary-amine capped cryptate and tetrahedral covalent cages.

Stable-isotope labeling coupled with liquid-phase separation and MS analysis is a powerful technique for comparative proteomics. We developed a dimethyl labeling strategy (Anal. Chem. 2003, 75, 6843-6852 and J. Proteome Res. 2005, 4, 101-108) to label peptide N-terminus and epsilon-amino groups of Lys with water-soluble formaldehyde via reductive methylation, and an isotopic pair of formaldehyde is used for binary labeling on two sets of samples. In this study, this approach is extended to a four sample labeling by combining the binary isotopic reagents of formaldehyde (d0, d2) and the binary isotopic reducing reagents, sodium cyanoborohydride (d0, d3). To ensure sufficient mass difference, this multiplexed labeling is coupled with endoproteinase Lys-C instead of trypsin for digestion, resulting in at least two labeling sites with a mass difference of 4 Da for each pair of peptide digest. Moreover, multiplex dimethyl labeling was proved to have no significant isotopic effect during RP LC elution. This method was further applied for monitoring Lys-C digestion using hemoglobin as a model. Dimethyl labeled digests derived from seven time points (1-30 h) were grouped into two sets of sample mixtures, separated by nano-LC to reduce the complexity, and then analyzed by ESI-MS/MS. The temporal study reveals that Lys-C digestion was completed in 10-15 h for all detected peptides. The multiplex dimethyl method has not only provided a simultaneous detection mean for four sample sets but has also conserved all the advantages associated with the original binary method.

The condensation of 1,1′-bis(6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline) with alkyl, aralkyl and aryl aldehydes, but not ketones, in ethanol or chloroform provides useful cyclic aminal [8-substituted 5,6,10,11,15b,15c-hexahydro-2,3,13,14-tetramethoxy-8H-imidazo[5,1-a:4,3-a′]diisoquinoline] intermediates that when subsequently treated with sodium cyanoborohydride in ethanol, followed by the addition of 2 M hydrochloric acid, gave monosubstituted N-alkyl 1,1′-bis(6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline) derivatives in very high yields. The rates of the initial condensation with four different aldehydes were measured, and the entire sequence was successfully applied in one example to a ‘one-pot’ process; this signals a versatile route to differentially N-substituted 1,1′-bis(1,2,3,4-tetrahydroisoquinoline) derivatives.

Caldaryomyces fumago chloroperoxidase (CPO) was treated with sodium cyanoborohydride and 9-antraldehyde (9A) for reductive alkylation and with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDAC) or with hexamethylendiamine (HMDA) for amidation. Furthermore, native CPO and amidated derivatives were cross-linked with glutaraldehyde (GA). The CPO derivatives highest overall activity levels were obtained in reaction mixtures presenting a molar excess of 1:100 where activity retention was 80% for alkylation and amidation and 70% for cross-linking reactions. The 9A and GA treatments resulted in 4 and 8% decrease of free amino groups while the EDAC and HMDA treatments resulted in an increase of 9–11%. Further GA cross-linking treatments decrease the free amino groups around 20%. CPO derivatives pH and temperature profiles were similar to that of the native CPO, presenting maximum activity at pH 6.0 and 30 °C. CPO–EDAC and CPO–HMDA and all GA cross-linked derivatives presented 40% residual activity after incubation for 120 min at 60 °C in pH 6.0, and during 60 min at 30 °C in pH 7.0, conditions that completely inactivated the native CPO. The CPO–9A derivative presented a four-fold hydrophobicity increase and the CPO–GA showed to be 30% more stable than the native enzyme in 60% tert -butanol.

1,4-Linked β-d-galactooligosaccharides with a degree of polymerization (DP) between 1 and 7 and 1,5-linked α-l-arabinooligosaccharides with a DP between 1 and 8 were labeled at their reducing ends with 2-aminobenzamide (2AB) in the presence of sodium cyanoborohydride. The 2AB-labeled oligosaccharides were shown to be homogeneous using high-performance anion-exchange chromatography (HPAEC) and by electrospray ionization mass spectrometry (ESI-MS). The signals in the 1H and 13C nuclear magnetic resonance (NMR) spectra of the 2AB-labeled oligosaccharides were then assigned using one- and two-dimensional NMR spectroscopy. These NMR data will be useful for the structural analysis of enzymatically synthesized galactan and arabinan side chains derived from rhamnogalacturonan I.

— Reductive amination of 4-formyl[benzo-15-crown-5] with sodium cyanoborohydride in the NH 4 Ac/MeOH mediumfollowed by acid addition and extraction with CHCl 3 unexpectedly lead to the isolation of the salt (B15C5-CH 2 -NH 3 ) + -(H 3 BCNBH 2 CN) − with an unusual dicyanodiborohydride anion. The self-complementary 4-ammoniomethyl[benzo-15-crown-5]cation was found to exist as a supramolecular dimer in the solid state, acetonitrile solution, and gas phase as revealed by X-raycrystallography, NMR and mass spectrometry, respectively. © 2003 Elsevier Science Ltd. All rights reserved. Self-complementary monofunctionalized crown-ethershave proved to be useful building blocks forsupramolecular architecture. 1–5 Stoddart and co-work-ers successfully explored systems based on protonatedsecondary ammonium or 4,4-dipyridinium functionali-ties threaded through large ( 24-membered) crownethers. 2–4 Very recently, we 5 and others 6 reported crys-talline dimers obtained from simple self-complementaryaminomethylcrown ethers (benzo-18-crown-6 andcrown-5, respectively). The ‘non-threaded’ dimer basedon a well-known host–guest motif, namely benzo-18-crown-6 and R-NH

Linear block copolymers of polystyrene and polysaccharide were synthesized using a block synthesis method with amino-terminated polystyrene and sodium cyanoborohydride as reducing agent. Different types of polysaccharides, dextrans, and maltodextrins with various molecular weights were used. IR spectroscopy indicated a successful coupling. Yields of reaction are 75-95 wt %. Attempts to couple long dextrans (Mw > 6000 Da) were not successful. Interfacial pressure measurements of monolayers of the copolymers on water showed interfacial behavior typical for amphiphilic compounds and different from the starting compounds, confirming the coupling reaction. Time-dependent hysteresis occurs between successive compression and expansion cycles. This is, to a large extent, due to the slow adsorption/desorption of the polysaccharide chains at the air-water interface and the formation of aggregates of copolymer at the interface. Aggregates are mainly formed by H-bonds between adjacent polysaccharide chains. The relaxation time for hysteresis, determined for polystyrene - dextran copolymer, was 85 min.

A modified polysulfone containing benzylamine groups was synthesized as a reactive membrane material. Polysulfone was activated at the ortho-sulfone site by direct lithiation with n-butyllithium, and the resulting lithiated polysulfone was then reacted with benzonitrile; this yielded a polymer with pendant benzimine groups. The structure was confirmed by NMR and IR spectroscopy and by the transformation of imine to ketone by acid hydrolysis. The polymeric benzimine was also reduced to benzylamine with sodium cyanoborohydride in an acidic medium. The structure and degree of substitution of both benzylamine derivatives were determined by NMR and IR spectroscopy. The modified polysulfone containing benzylamine groups initiated the polymerization of N-carboxyanhydride of γ-benzyl-L-glutamate [Glu(OBzl)–NCA]. The side-chain oligopeptide of Glu(OBzl)–NCA attached to polysulfone was converted into molecular recognition sites. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1316–1329, 2003