Characterization of Structural Transition and Heterogeneity under Compression for Liquid Al2O3 Using Molecular Dynamics Simulation

We have performed a simulation of the structural transition and Structural Heterogeneity (SH) in liquid Al2O3 at 3500 K, in the range of 0–100 GPa. The results confirmed that the network structure of liquid alumina is built mainly from AlOx (x = 3, 4, 5, 6, 7) units, which are related to each other through the common oxygen atoms. The existence of separate AlO3-, AlO4-, AlO5-, AlO6- and AlO7- phases, where SH of the network structure can be sufficiently determined, besides, the existence of separate phases is clarified for SH in the liquid of Al2O3. In particular, at a pressure below 10 and beyond 20 GPa, AlOx units are uniformly distributed in the space and non-uniformly distributed in the range 10-20 GPa. Our study is expected to contribute to a simple way to determine the structural heterogeneity and diffusion coefficients of oxide systems. Doi: 10.28991/HIJ-2022-03-02-08 Full Text: PD

Synthesis of antiulcer drug esomeprazole.

Esomeprazole (Nexium®), the (S)-isomer of Omeprazole, is the first proton-pump inhibitor developed as a single isomer for the treatment of acid-related diseases. It is used for the treatment of peptic ulcers, gastroesophagal reflux disease, and erosive esophagitis. Herein, we report our synthetic study of esomeprazole sodium salt from the starting    2-mercapto-5-methoxybenzimidazole and 2-(chloromethyl)-4-methoxy-3,5-dimethylpyridine hydrochloride reagents. The Esomeprazole sodium salt was obtained from enantioselectivesulfoxidation reaction in moderate yield with high enantioselectivity

Synthesis and biological evaluation of shikimic acid derivatives

From shikimic acid, new series of oseltamivir analogues containing either ether sulfur or ether oxygen at C-3 position were prepared and evaluated for their biological activities. This is the first report on synthesis of oseltamivir analogues with ether sulfur at C-3. Except for compounds 4d, 4f, 7c and 7d, the remaining compounds were found to be active against MCF-7, LU-1 and KB cell lines. As oseltamivir had no cytotoxicity against different cell lines such as MCF-7, LU-1, KB, MDCK, MRC-5, VERO, MK and 293, the modification of alkyl groups at C-3 of the oseltamivir ring framework could significantly increase the cytotoxicity for this class of compounds. Loss of neuraminidase inhibition activity of these synthetic oseltamivir analogues suggested that the alkyl ether groups at C-3 should be critical for their anti-neuraminidase activity

Eupolauridine alkaloids of Polyalthia nemoralis

Two eupolauridine alkaloids, eupolauridine (1) and 8-methoxyeupolauridine (2), together with a phenanthrene compound, 2,7-dihydroxy-3,6-dimethoxyphenanthrene (3), were isolated from the ethyl acetate extract of Polyalthia nemoralis barks. Their structures were elucidated on the basis of spectroscopic analysis and comparison with related known compounds. These compounds were evaluated the cytotoxicity on seven human cancer cell lines including KB, MCF7, LU-1, HepG2, LNCap, SW626 and SW480

Lignans isolated from the ethyl acetate extract of Knema pachycarpa fruit

Knema is a genus of tropical evergreen trees of the family Myristicaceae found in South East Asian countries such as Vietnam, Thailand, and Malaysia. In this paper, four lignans, (+)-pinoresinol (1),(+) epi-pinoresinol (2), piperitol (3), and pluviatilol (4), were isolated from the ethyl acetate extract of the fruit of Knema pachycarpa, an indigenus tree in Vietnam. The chemical structures were determined by spectroscopic data and comparison with the reported literature. These compounds were isolated from Knema genus for the first time. Keywords. Knema pachycarpa de Wilde, (+)-Pinoresinol, (+)-Epi-pinoresinol, Piperitol, Pluviatilol

A practical synthesis of fluoroquinolone antibiotic moxifloxacin

The fluoroquinoloneantibiotic has been used in clinical practice since the 1980s, primarily for the treatment infections caused by Gram-negative bacteria. Moxifloxacin, a fourth-generation fluoroquinolone antibiotic developed by pharmaceutical company Bayer AG, exhibit broad spectrum of activity against Gram-negative, Gram-positive bacteria as well as  anaerobia. Moxifloxacin is used for community-acquired respiratory tract infections, sinusitis, acute exacerbations of chronic bronchitis and pneumonia, and skin structure infections. We have described the synthesis of moxifloxacin using difluoroboron complex. In this paper, a practical synthesis of moxifloxacin using acetoxyboronate complexwas reported

Cellobiose dehydrogenase from the agaricomycete Coprinellus aureogranulatus and its application for the synergistic conversion of rice straw

From the biotechnological viewpoint, the enzymatic disintegration of plant lignocellulosic biomass is a promising goal since it would deliver fermentable sugars for the chemical sector. Cellobiose dehydrogenase (CDH) is a vital component of the extracellular lignocellulose-degrading enzyme system of fungi and has a great potential to improve catalyst efficiency for biomass processing. In the present study, a CDH from a newly isolated strain of the agaricomycete Coprinellus aureogranulatus (CauCDH) was successfully purified with a specific activity of 28.9 U mg(-1). This pure enzyme (MW = 109 kDa, pI = 5.4) displayed the high oxidative activity towards beta-1-4-linked oligosaccharides. Not least, CauCDH was used for the enzymatic degradation of rice straw without chemical pretreatment. As main metabolites, glucose (up to 165.18 +/- 3.19 mg g(-1)), xylose (64.21 +/- 1.22 mg g(-1)), and gluconic acid (5.17 +/- 0.13 mg g(-1)) could be identified during the synergistic conversion of this raw material with the fungal hydrolases (e.g., esterase, cellulase, and xylanase) and further optimization by using an RSM statistical approach

Two new sesquiterpenes from the fruits of <i>Fissistigma villosissimum</i>

<p>Two new sesquiterpenes, namely fissistinone (<b>1</b>) and fissistinol (<b>2</b>), along with ten known compounds (<b>3–12</b>), were isolated from the fruits of <i>Fissistigma villosissimum</i>. Their structures were elucidated on the basis of spectral data analysis, including one-dimensional (1D), two-dimensional (2D)-nuclear magnetic resonance (NMR), and high-resolution–electrospray ionization–mass spectrometry (HR–ESI–MS). Compounds <b>1</b>–<b>8</b> were evaluated for their cytotoxic activities against KB cell line; however, all these compounds did not show cytotoxic activity.</p

Synthesis and biological evaluation of shikimic acid derivatives

From shikimic acid, new series of oseltamivir analogues containing either ether sulfur or ether oxygen at C-3 position were prepared and evaluated for their biological activities. This is the first report on synthesis of oseltamivir analogues with ether sulfur at C-3. Except for compounds 4d, 4f, 7c and 7d, the remaining compounds were found to be active against MCF-7, LU-1 and KB cell lines. As oseltamivir had no cytotoxicity against different cell lines such as MCF-7, LU-1, KB, MDCK, MRC-5, VERO, MK and 293, the modification of alkyl groups at C-3 of the oseltamivir ring framework could significantly increase the cytotoxicity for this class of compounds. Loss of neuraminidase inhibition activity of these synthetic oseltamivir analogues suggested that the alkyl ether groups at C-3 should be critical for their anti-neuraminidase activity