Anodic Oxidation: An Attractive Alternative to CAN‐Mediated Cleavage of <i>para</i>‐Methoxyphenyl Ethers

“…of CAN at 0 °C for 30 min in water solution was based on the reported cleavage of the similar p-methoxyphenyl group. 11 However, a yield of less than 5%, detected by LC-MS, of desired trisaccharide was observed. Instead, an unexpected disaccharide was obtained in 80% yield and its structure was confirmed, using MS and NMR, to be missing the reducing-end GlcA residue.…”

Section: Introductionmentioning

confidence: 98%

“…However, general and practical methods for deprotection of p -NP group are not well established, even though some successful examples have been reported on the protected sugar substrates 10 or the similar substrates taged with p-nitrobenzyl ( p -NPM), p-methoxybenzyl ( p -MPM) and p-pivaloylaminobenzyl ( p -PAB) groups. 11 In this communication, we examined the oxidative deprotection of p -NP group with cerium reagents under mild oxidative conditions.…”

Section: Introductionmentioning

confidence: 99%

Toward the chemoenzymatic synthesis of heparan sulfate oligosaccharides: oxidative cleavage of p-nitrophenyl group with ceric ammonium salts

Cai

Harvey

et al. 2013

Tetrahedron Letters

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We have developed an efficient chemoenzymatic synthesis of heparan sulfate oligosaccharides employing the para-nitrophenyl (p-NP) β-glucuronide as an acceptor compatible with enzymatic elongation and one that significantly simplifies oligosaccharide purification on C-18 resin. Employing ceric ammonium nitrate as oxidative reagent to remove the p-NP group unexpectedly also removed the glucuronic acid residue at the reducing-end, affording a smaller oligosaccharide. The application of ceric ammonium sulfate allowed the removal of the p-NP without concomitant loss of the adjacent glucuronic acid offering a route to longer heparin sulfate oligosaccharide products.

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“…AACC experienced recently a tremendous development as an efficient, selective, but also mild and functional-group-tolerant coupling chemistry. [37,38] While electrochemically addressable protection groups are known for a variety of functional groups, [39][40][41][42][43][44][45] there are no suitable masking groups for alkynes reported so far to the best of our knowledge. [37,38] While electrochemically addressable protection groups are known for a variety of functional groups, [39][40][41][42][43][44][45] there are no suitable masking groups for alkynes reported so far to the best of our knowledge.…”

Section: Introductionmentioning

confidence: 99%

“…[35,36] Its integration in a novel constructive surface built-up concept would be ideal as it proved to be useful for the further functionalization of surfaces exposing alkyne groups with azide derivatives. [37,38] While electrochemically addressable protection groups are known for a variety of functional groups, [39][40][41][42][43][44][45] there are no suitable masking groups for alkynes reported so far to the best of our knowledge. We became thus interested in electrochemically triggerable protection groups for alkynes as individually addressable electrodes would facilitate a siteselective molecular assembly for the reasons given above.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Multiplexing: Control over Surface Functionalization by Combining a Redox‐Sensitive Alkyne Protection Group with “Click”‐Chemistry

Hellstern

Gantenbein

Puebla‐Hellmann

et al. 2019

Adv Materials Inter

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and molecular electronics, [11,12] over medical diagnostic devices [13][14][15] to applications tuning macroscopic and/or environmental features like, e.g., the wettability [16][17][18] or the biocompatibility [19][20][21] of material surfaces. In most cases, a bifunctional molecule, combining an anchor group attaching the molecular compound to the surface with an exposed subunit representing the active moiety with tailored physiochemical properties is used to tune the surface's terminal appearance. While such approaches are successfully applied for entire objects and surfaces of considerable dimensions and macroscopic separations, there are limitations as soon as spatial patterns of varying surface functionalities and microscopic separations are desired or a spatially constrained surface-access including buried microfluidic chips has to be overcome. For example, conventional wet chemical surface functionalization procedures are spatially limited to the size of the droplet deposited (and its subsequent surface interaction) and methods depositing the molecules from gas-phase in vacuum require advanced masking strategies. Challenging are devices with a variety of molecular features to be created in a parallel process and in a locally controlled manner, like, e.g., multidimensional sensing platforms where a multitude of nearby molecular receptors are screening analytes in parallel. Or microfluidic chips with constrained access to functional sites as the channels are locally enclosed and inaccessible for droplet deposition. Of great interest are devices analyzing molecular binding events electronically, due to their miniaturization potential and the analyte-selective binding without the requirement of labels. In such devices, each electrode is electrically addressable in a separated manner as they were contacted individually. Such a preexisting electrical wiring scheme is a unique feature for an immobilization strategy able to distinguish between the applied electrical potentials of each electrode and a common electrolyte. The electrochemical release of thiol-based self-assembled monolayers (SAMs) on gold electrodes has been reported. [22] This allows the disintegration of existing SAMs. The subsequent decoration of the liberated electrode with an alternative thiol-molecule, however, is handicapped by scrambling with the remaining SAMs. Electrochemical triggered constructive build-up of molecular Local functionalization of surfaces is a current technological challenge. An electrochemically addressable alkyne protection group is presented enabling the site-selective liberation of alkynes exclusively on electrified electrodes. This controlled deprotection is based on a mendione chromophore which becomes a strong enough nucleophile upon reduction to intramolecularly attack the trialkylsilane alkyne protection group. The site-selective liberation of the alkyne is demonstrated by immobilizing the protected alkyne precursor on a transparent TiO 2 electrode and subsequently immobilizing red and blue azide dyes by azide-alky...

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Anodic Oxidation: An Attractive Alternative to CAN‐Mediated Cleavage of para‐Methoxyphenyl Ethers

Cited by 11 publications

References 17 publications

Synthetic Organic Electrochemical Methods Since 2000: On the Verge of a Renaissance

Synthetic Organic Electrochemical Methods Since 2000: On the Verge of a Renaissance

Toward the chemoenzymatic synthesis of heparan sulfate oligosaccharides: oxidative cleavage of p-nitrophenyl group with ceric ammonium salts

Electrochemical Multiplexing: Control over Surface Functionalization by Combining a Redox‐Sensitive Alkyne Protection Group with “Click”‐Chemistry

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