Overview Contents: Chem. Eng. Technol. 4/2024
Chemical Engineering &Technology, Volume 47, Issue 4, Page 613-613, April 2024.
Editorial Board: Chem. Eng. Technol. 4/2024
Chemical Engineering &Technology, Volume 47, Issue 4, Page 612-612, April 2024.
Overview Contents: Chemie Ingenieur Technik 4/2024
Chemical Engineering &Technology, Volume 47, Issue 4, Page 746-746, April 2024.
Genetically Encoded Lysine Analogues with Differential Light Sensitivity for Activation of Protein Function
Genetically encoded unnatural amino acids are useful tools for controlling protein function, but options for sequential activation of proteins using light as a trigger are limited. Here, we report the genetic encoding of two new photocaged lysine derivatives for activation of protein function, such as protein translocation and bioluminescence, with two different wavelengths of light and/or different durations of light exposure.
Abstract
Genetically encoded unnatural amino acids are versatile tools for controlling protein function, but options for regulating multiple proteins in a single experiment are limited. Here, we report the genetic encoding of two new photocaged lysine derivatives, 1-(2-nitrophenyl)-ethyl lysine and nitrodibenzylfuranyl lysine, for sequential light-activation of protein function in live cells. Nitrodibenzylfuranyl (NDBF) caging groups have a redshifted absorbance maximum and high sensitivity to light compared to the 1-(2-nitrophenyl)-ethyl group (NPE), enabling selective decaging and protein activation. We characterized the responses of these new caged amino acids by optically triggering nuclear localization and firefly luciferase activity. The ability to selectively activate distinct proteins through simple light titration makes this a useful approach with broad applications.
Metal‐Free Electrochemical Trifluoromethylation of Imidazole‐Fused Heterocycles with Trifluoromethyl Thianthrenium Triflate
We present a novel and eco-friendly electrochemical strategy for the electrochemical activation of trifluoromethyl thianthrenium triflate to access trifluoromethylated imidazo-fused heteroaromatic compounds.
Comprehensive Summary
A novel and eco-friendly electrochemical activation of trifluoromethyl thianthrenium triflate (TT–CF3 +OTf−) for trifluoromethylation of imidazole-fused heteroaromatic compounds was established. This method involves the direct electrolysis of TT–CF3 +OTf− without the requirement of external oxidants or catalysts, aligning with the principles of green chemistry. A wide range of imidazole-fused heteroaromatic compounds including imidazo[1,2-a]pyridines and benzo[d]imidazo[2,1-b]thiazoles have been successfully trifluoromethylated using this technique, exhibiting excellent compatibility with various functional groups and a broad substrate scope. Moreover, the method's applicability for one-pot sequential reactions enables the reduction of waste and resource consumption by eliminating the need for intermediate purification steps.
Ru(II)‐Catalyzed Selective C—H Alkynylation of Isoquinolones, Quinazolones and Phthalazinones with Bromoalkynes
We reported Ru(II)-catalyzed C—H alkynylation of isoquinolones, quinazolones and phthalazinones with bromoalkynes. This protocol provides an approach towards access to various heterocyclic compounds in high yields (up to 95%).
Comprehensive Summary
A new, selective Ru(II)-catalyzed alkynylation reaction of isoquinolones, quinazolones and phthalazinones with readily available bromoalkynes has been developed. This reaction enables the selective construction of a new C(sp2)-C(sp) bond through C—H activation and C—Br functionalization, and offers an effective and selective route to synthesizing highly valuable alkynylated isoquinolone, quinazolone and phthalazinone derivatives with a wide substrate scope and high selectivity.
Random Terpolymer of Carbon Dioxide, Butadiene and Epoxides: Synthesis, Functionalization and Degradability
The terpolymer of CO2, 1,3-butadiene and epoxides is synthesized by cationic ring-opening copolymerization of α-ethylidene-δ-vinyl-δ-valerolactone (EVL), an intermediate derived from CO2 and 1,3-butadiene, with epoxides. The resulted poly(ester-ether) with moderate molecular weight bears all the C=C double bonds derived from 1,3-butadiene, enabling post-polymerization modification and functionalization. Photoinitiated crosslinking through these preserved C=C double bonds produces network with fluorescence and degradation properties.
Comprehensive Summary
The utilization of carbon dioxide (CO2) as a C1 feedstock is consistently attractive, especially in the preparation of sustainable polymeric materials. In this contribution, a terpolymer of CO2, 1,3-butadiene (BD) and epoxide is synthesized by scandium triflate catalyzed cationic ring-opening copolymerization of α-ethylidene-δ-vinyl-δ-valerolactone (EVL), an intermediate derived from CO2 and BD, with epoxides. The obtained terpolymer with a CO2 content of 22 mol% has a number-average molecular weight (M n) up to 7.8 kg/mol and a dispersity (Đ) of 2.4. The reactivity ratios of EVL and cyclohexene oxide (CHO) are determined as 0.01 and 1.07, respectively, suggesting random characteristic of the terpolymer. The preserved C=C double bonds from BD allow for the further modification of the terpolymer by photoinitiated crosslinking. The yielded networks are fluorescent and degradable. This method offers enhanced versatility to the synthesis and additional functionalization of CO2-based polymers.
Cycloaddition Reactions of Epoxides and CO2 Catalyzed by Bifunctional Rare‐Earth Metal Complexes Bearing Amino‐Bridged Tris(phenolato) Ligands
Bifunctional rare earth complexes have been developed for the cycloaddition reactions of epoxides and CO2, under atmospheric pressure, without co-catalyst to produce value-added cyclic carbonates. Comparative and kinetic experiments confirm the existence of intramolecular synergies between the central metal and the nucleophilic reagent within the catalytic molecule.
Comprehensive Summary
Eight zwitterionic rare earth metal complexes stabilized by amino-bridged tris(phenolato) ligands bearing quaternary ammonium side-arms were synthesized and characterized. These complexes were used as single-component catalysts for the cycloaddition of CO2 and epoxides, and their catalytic activities are obviously higher than those of their binary analogues. Further studies revealed that the halide anions (Cl–, Br–, I–) and the metal complexes influenced the catalytic activity, and the lanthanum complex bearing iodide anion showed the highest catalytic activity for this addition reaction. A variety of mono-substituted epoxides were converted to cyclic carbonates in good to excellent yields (55%—99%) with high selectivity (> 99%) at 30 °C and 1 bar CO2, whereas internal epoxides required higher both reaction temperatures (60—120 °C) and catalyst loading (2 mol%) for high yields. The catalyst was recyclable for four times without noticeable loss of catalytic activity. Based on the results of kinetic studies and in situ IR reactions, a plausible reaction mechanism was proposed.
[ASAP] Heterogeneous Coprecipitation of Nanocrystals with Metals on Substrates
Accounts of Chemical Research
DOI: 10.1021/acs.accounts.3c00807
Lewis Base Catalyzed Selenofunctionalization of Alkynes with Acid‐Controlled Divergent Chemoselectivity
Lewis base catalyzed and Brønsted acid controlled chemodivergent electrophilic selenofunctionalizations of alkynes were developed for the first time. Various selenium-containing tetrasubstituted alkenes were readily obtained in moderate to excellent yields with complete E/Z selectivities.
Comprehensive Summary
Lewis base catalyzed and Brønsted acid controlled chemodivergent electrophilic selenofunctionalizations of alkynes were developed for the first time. Various selenium-containing tetrasubstituted alkenes were readily obtained in moderate to excellent yields with complete E/Z selectivities. As the substrates were 1-ethynyl naphthol derivatives, linear selenium-containing tetrasubstituted alkenes were produced via intermolecular oxygen nucleophilic attack in the absence of acid additive; in contrast, cyclic selenium-containing tetrasubstituted alkenes were generated through intramolecular carbon nucleophilic capture with the addition of Brønsted acid.