Borohydride Exchange Resin Research Articles

Reducing Hexavalent Chromium to Trivalent Chromium with Zero Chemical Footprint: Borohydride Exchange Resin and a Polymer-Supported Base.

Aqueous hexavalent chromium, Cr(VI), is rapidly reduced to trivalent chromium, Cr(III), by exposure to (polystyrylmethyl)trimethylammonium borohydride and with Amberlite-supported mild bases in a heterogeneous environment. Post-reaction removal of the insoluble reagents leaves no remediation-based chemical footprint in the source water. Time dependence with stirred and static conditions is discussed.

An Efficient Method for the Surface Functionalization of Luminescent Quantum Dots with Lipoic Acid Based Ligands

We describe herein an operationally advantageous general methodology for efficiently activating lipoic acid based compounds, a family of popular surface ligands for semiconductor nanocrystals, through the use of a borohydride exchange resin, and the use of the activated species to replace the native surface ligands of quantum dots. The procedure enabled phase transfer of the nanocrystals between polar and aqueous media and, if unsubstituted lipoic acid was used, a facile adjustment of their solubility in a wide range of solvents with varying polarity (from hexane to water). We show that the protocol is applicable to different types of nanocrystals and a variety of lipoic acid based ligands, and that the resulting quantum dots maintain their optical properties, in particular, an intense luminescence, and long‐term colloidal stability.

Selenium borohydride reaction as a versatile platform for the straightforward preparation of selenide-containing topological polymers

A simple and versatile method for preparing selenide-containing polymers with desired topologies is established based on the reaction of a selenide-functionalized borohydride exchange resin with end-functionalized polymers.

De novo synthesis of 1-deoxythiosugars

A short and efficient chemical synthesis of biologically potent and novel 1-deoxythiosugars is accomplished. Introduction of sulfur mediated by benzyltriethylammonium tetrathiomolybdate, as a sulfur transfer reagent through nucleophilic double displacement of tosylate in α,ω-di-O-tosyl aldonolactones in an intramolecular fashion is the key feature. The subsequent reduction of thiosugar lactones with borohydride exchange resin (BER) offers a number of deoxythiosugars in good overall yield.

Fully automated synthesis of 4-[18F]fluorobenzylamine based on borohydride/NiCl2 reduction

4-[(18)F]Fluorobenzylamine ([(18)F]FBA) is an important building block for the synthesis of (18)F-labeled compounds. Synthesis of [(18)F]FBA usually involves application of strong reducing agents like LiAlH4 which is challenging to handle in automated synthesis units (ASUs). Therefore, alternative methods for the preparation of [(18)F]FBA compatible with remotely-controlled syntheses in ASUs are needed. (18)F]FBA was prepared in a remotely-controlled synthesis unit (GE TRACERlab™ FX) based on Ni(II)-mediated borohydride exchange resin (BER) reduction of 4-[(18)F]fluorobenzonitrile ([(18)F]FBN). [(18)F]FBA was used for the synthesis of novel thiol-reactive prosthetic group 4-[(18)F]fluorobenzyl)maleimide [(18)F]FBM and Hsp90 inhibitor 17-(4-[(18)F]fluorobenzylamino)-17-demethoxy-geldanamycin [(18)F] GA. [(18)F]FBA could be prepared in high radiochemical yield greater than 80% (decay-corrected) within 60min. In a typical experiment, 7.4GBq of [(18)F]FBA could be obtained in high radiochemical purity of greater than 95% starting from 10GBq of cyclotron-produced n.c.a. [(18)F]fluoride. [(18)F]FBA was used for the preparation of 4-[(18)F]fluorobenzyl)maleimide as a novel prosthetic group for labeling of thiol groups as demonstrated with tripeptide glutathione. [(18)F]FBA was also used as building block for the syntheses of small molecules as exemplified by the preparation of Hsp90 inhibitor 17-(4-[(18)F]fluorobenzylamino)-17-demethoxy-geldanamycin. The described remotely-controlled synthesis of [(18)F]FBA will significantly improve the availability of [(18)F]FBA as an important and versatile building block for the development of novel (18)F-labeled compounds containing a fluorobenzylamine moiety.

Enantioselective and Protecting Group-Free Synthesis of 1-Deoxythionojirimycin, 1-Deoxythiomannojirimycin, and 1-Deoxythiotalonojirimycin

1-Deoxythioglyconojirimycins were synthesized by using a protecting group-free strategy, starting from readily available carbohydrates, in good overall yield. Use of benzyltriethylammonium tetrathiomolybdate, [BnEt(3)N](2)MoS(4), as a sulfur transfer reagent and borohydride exchange resin (BER) reduction of a lactone enabled the efficient synthesis of the title compounds.

ChemInform Abstract: Reduction of Nitro Compounds with Borohydride Exchange Resin - Nickel Acetate.

ChemInform Abstract: Reduction of Nitro Compounds with Borohydride Exchange Resin - Nickel Acetate.

Synthesis and application of 4-[18F]fluorobenzylamine: A versatile building block for the preparation of PET radiotracers

A novel synthesis of 4-[(18)F]fluorobenzylamine ([(18)F]FBA) by means of transition metal-assisted sodium borohydride reduction of 4-[(18)F]fluorobenzonitrile ([(18)F]FBN) is described. This approach could successfully be extended to borohydride exchange resin (BER) enabling a viable option for use in automated syntheses. [(18)F]FBA was used for the synthesis of 4-[(18)F]fluorobenzylamine-based thiol group-reactive prosthetic groups 4-[(18)F]fluorobenzyl-2-bromoacetamide ([(18)F]FBBA) and 4-[(18)F]fluorobenzylamidopropionyl maleimide ([(18)F]FBAPM). [(18)F]FBBA and [(18)F]FBAPM were obtained in radiochemical yields of 75% and 55%, respectively. Feasibility of using [(18)F]FBAPM as novel prosthetic group for peptide and protein labelling was demonstrated with cysteine-containing tripeptide glutathione (GSH). [(18)F]FBBA was used for labelling of a fully phosphorothioated 20mer oligodesoxynucleotide (ODN).

ChemInform Abstract: Direct Reductive Amination of Aldehydes and Ketones with 2,4‐Ionene‐Based Borohydride Exchange Resin as a Novel Polymer‐Supported Reducing Agent.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Direct Reductive Amination of Aldehydes and Ketones with 2,4-Ionene-Based Borohydride Exchange Resin as a Novel Polymer-Supported Reducing Agent

Direct reductive amination of aldehydes and ketones were accomplished efficiently using high-capacity, ionene-based, polymer-supported borohydride reagent in isopropyl alcohol at reflux under neutral conditions. The reagent is easily prepared by mixing aqueous solution of 2,4-ionene bromide with an alkaline solution of sodium borohydride at room temperature. The generality of reaction was established using both aliphatic and aromatic aldehydes, ketones, and amines.

Highly Efficient Synthesis and Imaging Studies of an Arylpiperazine Derivative as a 5-HT1A Receptor Imaging Agent

Abstract A novel and straightforward microwave synthesis of a new arylpiperazine derivative 3 which has an N2S2 moiety has been developed and radiolabeled with an optimum radionuclide of technetium in the presence of a borohydride exchange resin (BER) as a reducing agent. According to the present study this new radiolabeled compound 4 could have the potential for a diagnostic application as an imaging agent of a serotonin neuroreceptor.

Novel and Efficient Preparation of Precursor [188Re(OH2)3(CO)3]+ for the Labeling of Biomolecules

A novel and efficient method for preparing 188Re(I) tricarbonyl precursor [188Re(OH2)3(CO)3]+ has been developed by reacting [188Re]perrhenate with Schibli's kit in the presence of borohydride exchange resin (BER) as a reducing agent and an anion scavenger. The precursor was produced in more than 97% yield by reacting a solution of tetrahydroborate exchange resin (BER, 3 mg), borane-ammonia (BH3.NH3, 3 mg), and potassium boranocarbonate (K2[H3BCO2], 3 mg) in 0.9% saline with a solution of sodium perrhenate (Na188ReO4) with up to 50 MBq and concentrated phosphoric acid (85%, 7 microL) at 60 degrees C for 15 min. HPLC and TLC revealed 0% unreacted [188Re]perrhenate ion and <3% of colloidal 188ReO2. Since the precursor is produced with high radiochemical purity and labeling efficiency under the milder conditions than those required for the conventional reducing agents, the latter can be replaced.

Selective Reduction of Nitrocinnamoylfumagillols with α,β‐Unsaturated Ester Using Borohydride Exchange Resin (BER)‐Nickel Acetate.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Simplified Preparation of Coniferyl and Sinapyl Alcohols

Coniferyl and sinapyl alcohols were prepared from commercially available coniferaldehyde and sinapaldehyde using borohydride exchange resin in methanol. This reduction is highly regioselective and exceptionally simple, making these valuable monolignols readily available to researchers lacking synthetic chemistry expertise.

Selective Reduction of Nitrocinnamoylfumagillols with α,β-Unsaturated Ester Using Borohydride Exchange Resin (BER)-Nickel Acetate

Borohydride Exchange Resin (BER) - nickel acetate system readily reduces nitrocinnamoylfumagillols to the corresponding amines in excellent yields, high chemoselectivity, and simple procedure. Especially, this system tolerates two epoxides (spiro-epoxide and the one on C4 alkene side chain) and the α,β-unsaturated ester moiety at C6 on the fumagillol.

Synthesis and characterization of 99mTc‐labelled biologically active molecules using borohydride exchange resin as a reducing agent for the preparation of radiopharmaceuticals

AbstractA novel and efficient method for preparing 99mTc‐complexes of radiopharmaceuticals has been developed by reacting [99mTc]pertechnetate with a ligand in the presence of borohydride exchange resin (BER) as a reducing agent. The latter is stable over a wide range of pH (2–11) and thus can be used with biologically active compounds without the formation of insoluble 99mTcO2 or SnO2 colloids. Since the radiolabelled complexes are produced with high radiochemical purity and labelling efficiency under milder conditions than those required for the conventional reducing agents, the latter can be replaced. The method is expected to be applicable to the preparation of 99mTc‐radiopharmaceuticals. Copyright © 2004 John Wiley &amp; Sons, Ltd.

Anomeric Activation of Thioglycosides and Preparation of Deoxyglycosides Using Polymer‐Bound Iodate(I) Complexes.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Anomeric activation of thioglycosides and preparation of deoxyglycosides using polymer-bound iodate(I) complexes

New thiophilic polymer-bound haloate(I) complexes are presented which are well suited for the polymer-assisted solution-phase activation of 2-deoxythioglycosides. In the presence of alcohols 2-deoxyglycosides are obtained in yields between 60 and 95%. Isolation of the target glycosides is further simplified by removing the byproduct diphenyldisulfide by reductive work-up. Here also a polymer-bound reagent, namely borohydride exchange resin, served as a tool for sequestering the sulfur-containing impurities.

Simultaneous determination of amphetamine and one of its metabolites by HPLC with electrochemical detection

A high-performance liquid chromatographic method coupled with electrochemical detector was developed for the separation and quantitation of amphetamine and one of its metabolites, the 4-hydroxynorephedrine. The pre-column derivatisation of these compounds was carried out with 2,5-dihydroxybenzaldehyde as electroactive labelling reagent, in presence of Borohydride Exchange Resin. The new synthetic method developed was fast, clean and high yielding. The analysis was performed in isocratic mode on a reversed phase column 5 μm Hypersil ODS RP-18, 15 cm, using as a mobile phase methanol-NaH 2PO 4 buffer (50 mM, pH 5.5)(30:70 v/v) containing trietylamine (0.5% v/v) and the products were detected by a porous graphite electrode set at an oxidation potential of +0.6 V. The linearity of response was examined for each derivatised compound and was analysed using solutions in the range 10–40 nmol/ml. The correlation coefficients of the linear regression of the standard curves were greater than 0.99. The method developed in this study was sensitive and very selective. Because of the specificity for primary phenylethylamines, it could be applicable for the assay of other related substances in toxicology and drugs abuse.

ChemInform Abstract: Reduction of Sulfur with Borohydride Exchange Resin in Methanol: Application to Rapid and Selective Synthesis of Disulfides.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.