Insights into the mechanism of energy transfer with poly(heptazine imide)s in deoximation reaction

Following our previous studies on potassium poly(heptazine imide) (K-PHI) – catalyzed photooxidative [3+2] aldoxime-to-nitrile addition to form 1,2,4-oxadiazoles, we discovered that electron-rich oximes yield the parent aldehydes instead of target products. In this work, the mechanism of this singlet oxygen-mediated deoximation process was established using a series of control reactions and spectroscopic measurements such as steady-state and time-resolved fluorescence quenching experiments. Additionally, singlet-triplet energy gap value was obtained for K-PHI in suspension, and the reaction scope was broadened to include ketoximes

Progress in development of photocatalytic processes for synthesis of fuels and organic compounds under outdoor solar light

With photovoltaics becoming a mature, commercially feasible technology, society is willing to allocate resources for developing and deploying new technologies based on using solar light. Analysis of projects supported by the European Commission in the past decade indicates exponential growth of funding to photocatalytic (PC) and photoelectrocatalytic (PEC) technologies that aim either at technology readiness levels (TRLs) TRL 1–3 or TRL > 3, with more than 75 Mio€ allocated from the year 2019 onward. This review provides a summary of PC and PEC processes for the synthesis of bulk commodities such as solvents and fuels, as well as chemicals for niche applications. An overview of photoreactors for photocatalysis on a larger scale is provided. The review rounds off with the summary of reactions performed at lab scale under natural outdoor solar light to illustrate conceptual opportunities offered by solar-driven chemistry beyond the reduction of CO2 and water splitting. The authors offer their vision of the impact of this area of research on society and the economy

Multisite PCET with photocharged carbon nitride in dark

A combination of photochemistry and proton coupled electron transfer (PCET) is a primary strategy employed by biochemical systems and synthetic chemistry to enable uphill reactions under mild conditions. Degenerate nanometer-sized n-type semiconductor nanoparticles (SCNPs) with the Fermi level above the bottom of the conduction band are strongly reducing and act more like metals than semiconductors. Application of the degenerate SCNPs is limited to few examples. Herein, we load microporous potassium poly(heptazine imide) (K-PHI) nanoparticles with electrons (e–) and charge balancing protons (H+) in an illumination phase using sacrificial agents. e–/H+ in the K-PHI nanoparticles are weakly bound and therefore could be used in a range of PCET reactions in dark, such as generation of aryl radicals from aryl halides, ketyl radicals from ketones, and 6e–/6H+ reduction of nitrobenzene to aniline. The integration of several features that until now were intrinsic for plants and natural photosynthesis into a transition metal free nanomaterial composed of abundant elements (C, N, and K) offers a powerful tool for synthetic organic chemistry

Enhanced organic photocatalysis in confined flow through a carbon nitride nanotube membrane with conversions in the millisecond regime

Bioinspired nanoconfined catalysis has developed to become an important tool for improving the performance of a wide range of chemical reactions. However, photocatalysis in a nanoconfined environment remains largely unexplored. Here, we report the application of a free-standing and flow-through carbon nitride nanotube (CNN) membrane with pore diameters of 40 nm for confined photocatalytic reactions where reactants are in contact with the catalyst for 5 s–1. Such high rates are otherwise only known for special enzymes and are clearly attributed to the confinement of the studied reactions within the one-dimensional nanochannels of the CNN membrane. Namely, a concave surface maintains the internal electric field induced by the polar surface of the carbon nitride inside the nanotube, which is essential for polarization of reagent molecules and extension of the lifetime of the photogenerated charge carriers. The enhanced flow rate upon confinement provides crucial insight on catalysis in such an environment from a physical chemistry perspective. This confinement strategy is envisioned not only to realize highly efficient reactions but also to gain a fundamental understanding of complex chemical processes

Nitroazolopyrimidines – Attractive Structures in Medicinal Chemistry

We thank Russian Foundation for Basic Research (grant № 18-03-00787) for financial support

Cyanmorpholinoethylene in the synthesis of relevant azoloazines

Approach to the synthesis of promising azolopyrimidines containing a primary amino group by reactions of variously substituted aminoazoles with cyanmorpholinoethylene was developed. © 2019 Author(s)

Azoloazines as Perspective Antiglycating Agents for Therapy of Diabetes Complications

This work was supported by Russian Federation Ministry of education and science (grant № 4.6351.2017/8.9) and Russian Foundation for Basic Research (grant № 18-03-00787)

Atom-efficient synthesis of hybrid molecules combining fragments of triazolopyrimidines and 3-ethoxycarbonyl-1-ethyl-6-fluoroquinolin-4(1H)-one through 1,2,3-triazole linker

[Figure not available: see fulltext.] An atom-efficient method toward hybrid molecules via azide-alkyne cycloaddition of 7-azido-3-ethoxycarbonyl-1-ethyl-6-fluoroquinolin-4(1H)-one and novel perspective triazolopyrimidines has been developed. This procedure features mild conditions and a broad substrate scope including hydrophobic and hydrophilic triazolopyrimidines. The synthesized hybrid structures combine fragments of fluoroquinolone with proved antibacterial activity and triazolopyrimidines, which may act as structural analogs of adenosine receptor effectors or antiviral azoloazine heterocycles. © 2021, Springer Science+Business Media, LLC, part of Springer Nature.Russian Foundation for Basic Research, РФФИ: 18-03-00787 АWe wish to thank the Russian Foundation for Basic Research for financial support (grant 18-03-00787 А)

Cyanmorpholinoethylene in the Synthesis of Relevant Azoloazines

The results were obtained within the framework of the state task of the Ministry of education and science of Russia (4.6351.2017/8.9) and with the financial support of the Russian science Foundation (№ 17-13-01096)

6-Aminotriazolo[1,5-a]pyrimidines as precursors of 1,2,4-triazolo[5,1-b]purines

Triazolo[5,1-b]purines are rare structural analogues of natural nucleosides and nucleobases purine series. At the same time, prominent representatives of azolopurines exhibit a broad spectrum of antiviral effect, activity against of rheumatoid arthritis, psoriasis, Alzheimer’s, Parkinson’s and etc. Despite the practical value azolo[5,1-b]purines extremely sparingly represented in the chemical literature, due to the complexity of their synthesis. We suggest a convenient way to synthesize triazolopurines with aminotriazolo[1,5-a]pyrimidines (2) as available starting compounds obtained in good yield by reduction of nitro derivatives (1).The work was supported by RFBR grant 13-03-0086