Search results for "540 Chemistry and allied sciences"
showing 7 items of 77 documents
Electrochemical C−H Functionalization of (Hetero)Arenes—Optimized by DoE
2020
Abstract A novel approach towards the activation of different arenes and purines including caffeine and theophylline is presented. The simple, safe and scalable electrochemical synthesis of 1,1,1,3,3,3‐hexafluoroisopropanol (HFIP) aryl ethers was conducted using an easy electrolysis setup with boron‐doped diamond (BDD) electrodes. Good yields up to 59 % were achieved. Triethylamine was used as a base as it forms a highly conductive media with HFIP, making additional supporting electrolytes superfluous. The synthesis was optimized using Design of Experiment (DoE) techniques giving a detailed insight to the significance of the reaction parameters. The mechanism was investigated by cyclic volt…
Cell adhesion on UV-crosslinked polyurethane gels with adjustable mechanical strength and thermoresponsiveness
2021
Temperature-responsive polyurethane (PU) hydrogels represent a versatile material platform for modern tissue engineering and biomedical applications. However, besides intrinsic advantages such as high mechanical strength and a hydrolysable backbone composition, plain PU materials are generally lacking bio-adhesive properties. To overcome this shortcoming, the authors focus on the synthesis of thermoresponsive PU hydrogels with variable mechanical and cell adhesive properties obtained from linear precursor PUs based on poly(ethylene glycol)s (pEG) with different molar masses, isophorone diisocyanate, and a dimerizable dimethylmaleimide (DMMI)-diol. The cloud point temperatures of the dilute,…
Tapered copolymers of styrene and 4‐vinylbenzocyclobutene via carbanionic polymerization for crosslinkable polymer films
2019
Nickel‐Mediated Photoreductive Cross Coupling of Carboxylic Acid Derivatives for Ketone Synthesis**
2021
A simple photochemical, nickel-catalyzed synthesis of ketones starting from carboxylic acids is presented. Hantzsch-ester (HE) functions as a cheap, green and strong photoreductant upon visible-light excitation to facilitate radical generation and also engages in the Ni-catalytic cycle to restore the reactive species. With this dual role, HE allows for the coupling of a large variety of radicals (1°,2°, benzylic, α-oxy & α-amino) with aroyl and alkanoyl moieties, a new feature in the synthesis of ketones through dual nickel photoredox catalysis. With both precursors deriving from abundant carboxylic acids, this protocol is a welcome addition to the organic chemistry toolbox. The reactio…
Anodic Dehydrogenative Cyanamidation of Thioethers: Simple and Sustainable Synthesis of N‐Cyanosulfilimines
2021
Abstract A novel and very simple to perform electrochemical approach for the synthesis of several N‐cyanosulfilimines in good to excellent yields was established. This method provides access to biologically relevant sulfoximines by consecutive oxidation using electro‐generated periodate. This route can be easily scaled‐up to gram quantities. The S,N coupling is carried out at an inexpensive carbon anode by direct oxidation of sulfide. Therefore, the designed process is atom economic and represents a new “green route” for the synthesis of sulfilimines and sulfoximines.
Instant kit preparation of 68Ga-radiopharmaceuticals via the hybrid chelator DATA: clinical translation of [68Ga]Ga-DATA-TOC
2019
Purpose The widespread use of 68Ga for positron emission tomography (PET) relies on the development of radiopharmaceutical precursors that can be radiolabelled and dispensed in a simple, quick, and convenient manner. The DATA (6-amino-1,4-diazapine-triacetate) scaffold represents a novel hybrid chelator architecture possessing both cyclic and acyclic character that may allow for facile access to 68Ga-labelled tracers in the clinic. We report the first bifunctional DATA chelator conjugated to [Tyr3]octreotide (TOC), a somatostatin subtype 2 receptor (SST2)-targeting vector for imaging and functional characterisation of SSTR2 expressing tumours. Methods The radiopharmaceutical precursor, DATA…
Feedback and Communication in Active Hydrogel Spheres with pH Fronts: Facile Approaches to Grow Soft Hydrogel Structures
2021
Abstract Compartmentalized reaction networks regulating signal processing, communication and pattern formation are central to living systems. Towards achieving life‐like materials, we compartmentalized urea‐urease and more complex urea‐urease/ester‐esterase pH‐feedback reaction networks into hydrogel spheres and investigate how fuel‐driven pH fronts can be sent out from these spheres and regulated by internal reaction networks. Membrane characteristics are installed by covering urease spheres with responsive hydrogel shells. We then encapsulate the two networks (urea‐urease and ester‐esterase) separately into different hydrogel spheres to devise communication, pattern formation and attracti…