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Carmofur, a 5-fluorouracil (5-FU) derivative, was initially developed as an antineoplastic agent to treat colorectal cancer. Through drug repurposing efforts, it has been identified as a potent covalent inhibitor of the main protease of SARS-CoV-2 ([M.sup.pro]), making it a promising therapeutic agent against COVID-19. However, previous synthetic procedures suffer from low yields or long reaction times. In this study, benchtop [.sup.19]F nuclear magnetic resonance (NMR) spectroscopy enables the realtime quantitative monitoring and characterization of the synthesis of carmofur by providing kinetic insight. Furthermore, its proton lock capabilities no longer require the use of deuterated solvents and have enabled convenient and rapidly scalable synthesis of our compound. Here, we present the application of benchtop [.sup.19]F NMR as an efficient method for optimizing the synthesis of carmofur and its future application in the synthesis of related 5-FU analogs. Key words: carmofur, benchtop nuclear magnetic resonance spectroscopy, [.sup.19]F NMR, reaction monitoring, reaction optimization, Introduction Fluorinated bioactive small molecules have a remarkable role in modern medicinal chemistry, as the incorporation of fluorine into drug candidates enhances their bioavailability, metabolic stability, and binding affinity to [...]

Electrostatic doping-assisted phonon softening has been intensively investigated in semiconducting transition metal dichalcogenides (TMDCs), in which strong electron–phonon interactions can be achieved in thin layers. Though electron–phonon coupling plays an important role in structure phase transitions for metallic 2H-TaX2 (X = S, Se), it has been rarely studied under electrostatic doping. Here, the effect of electrostatic doping on the vibrational phonon modes of 2H-TaSe2 and 2H-TaS2 thin films is studied with ionic liquid gating by the electric-double-layer gating technique. Under a gate bias (VG) of 1.5 V, 2H-TaSe2 has a blue shift of 7 cm−1 and a red shift of 3 cm−1 for the in-plane (E2g) and out-of-plane vibration (A1g) modes, respectively, indicating a strong electron–phonon interaction in both intralayer and interlayer. By varying the thickness of the flakes, it has been found that there exists a threshold VG value for the stiffening of the E2g mode and the softening of the A1g mode because of the strong electrostatic screening effect at lower doping density. As the intensity of the E2g mode decreases with VG, an anomalous enhancement of the A1g phonons can be achieved, which is further convinced in TaS2. The asymmetric phonon evolution behavior is very different with that in the semiconducting TMDCs, which may provide useful information for understanding electron–phonon interplay in metallic layer materials. [ABSTRACT FROM AUTHOR]

Carmofur, a 5-fluorouracil (5-FU) derivative, was initially developed as an antineoplastic agent to treat colorectal cancer. Through drug repurposing efforts, it has been identified as a potent covalent inhibitor of the main protease of SARS-CoV-2 (Mpro), making it a promising therapeutic agent against COVID-19. However, previous synthetic procedures suffer from low yields or long reaction times. In this study, benchtop 19F nuclear magnetic resonance (NMR) spectroscopy enables the real-time quantitative monitoring and characterization of the synthesis of carmofur by providing kinetic insight. Furthermore, its proton lock capabilities no longer require the use of deuterated solvents and have enabled convenient and rapidly scalable synthesis of our compound. Here, we present the application of benchtop 19F NMR as an efficient method for optimizing the synthesis of carmofur and its future application in the synthesis of related 5-FU analogs. [ABSTRACT FROM AUTHOR]

Cesium lead bromide (CsPbBr3) perovskite has attracted great attention recently for its potentials for next-generation green-color lasing devices owing to the relatively high structural stability and the high emission efficiency among the perovskite family. Herein, we explore the origins of cavity modes in CsPbBr3 microplatelets (MPs) lasers by using angle-resolved microphotoluminescence Fourier imaging technique, which is still controversial so far. In-plane Fabry–Pérot (F-P) mode lasing transition to whispering-gallery-mode (WGM) lasing is verified at room temperature, which mostly occurs in large MPs with edge length (L) over 13 μm. The F-P lasing is suppressed upon decreasing L or increasing excitation density, and the WGM lasing is predominant for all MPs at high excitation density. Furthermore, the parity and symmetry of in-plane F-P modes are classified. These results advance the fundamental understanding of lasing modes in planar microcavities as well as their applications in on-chip interconnection and quantum optics. [ABSTRACT FROM AUTHOR]