Heterocyclic compounds from 3-(4-phenyl) benzoyl propionic acid

3-(4-Phenyl) benzoyl propionic acid was used as the starting material for the synthesisof furanones (2), pyrrolinones (5), pyridazinones (7), benzoxazinones (8) and quinazolinones (9-11). The behaviour of the derivatives of furanones and benzoxazinones toward different nucleophiles is reported.     

Influence of vanadium doping on the behavior of YBa_2Cu_3O_7-y

YBa2Cu3-xVxO7-y(x=0, 0.1, 0.2, 0.3, 0.4, 0.5 and 0.6) superconductors have been prepared. X-ray diffraction shows that the system remains orthorhombic for all compositions studied, but for x > 0.4 V2O5 was detected as an impurity phase. Substitution of V5+ for Cu2+ occurs in the Cu(2) sites on the Cu(2)-O planes. The introduction of the high valence element, vanadium, produces the extra free-electrons. These electrons recombine with the positive carrier of the system. It makes depression of the mobility and the Hall number of YBa2Cu3-xVxO7-v and also results in a depression of TC.     

CHEMILUMINESCENCE AND FLUORESCENCE OF THE EUROPIUM IONS-ADENINE NUCLEOTIDES SYSTEM AND ITS POSSIBLE BIOLOGICAL SIGNIFICANCE

Abstract— Chemiluminescence of the Eu(II)/Eu(III)-adenine nucleotide-H₂O₂ system and fluorescence of the Eu(III)-adenosine triphosphate system have been investigated. The spectral distribution of the chemiluminescence emission has shown an occurrence of three main bands (Λ=470–480,590–620 and ca. 700 nm). The energy transfer process from the adenosine triphosphate molecules to the Eu(III) ions has been observed in the fluorescence spectrum. The examined chemiluminescence and fluorescence spectra show that these both kinds of emission originate from the ⁵ D _***τ⁷F_*** ( n =1–4) transitions in the Eu(III) ions.     

Synthesis and Antiviral Evaluation of (1,4-Disubstituted-1,2,3-Triazol)-(E)-2-Methyl-but-2-Enyl Nucleoside Phosphonate Prodrugs

A series of hitherto unknown (1,4-disubstituted-1,2,3-triazol)-(E)-2-methyl-but-2-enyl nucleosides phosphonate prodrugs bearing 4-substituted-1,2,3-triazoles were prepared in a straight approach through an olefin acyclic cross metathesis as the key synthetic step. All novel compounds were evaluated for their antiviral activities against HBV, HIV and SARS-CoV-2. Among these molecules, only compound 15j, a hexadecyloxypropyl (HDP)/(isopropyloxycarbonyl-oxymethyl)-ester (POC) prodrug, showed activity against HBV in Huh7 cell cultures with 62% inhibition at 10 μM, without significant cytotoxicity (IC₅₀ = 66.4 μM in HepG2 cells, IC₅₀ = 43.1 μM in HepG2 cells) at 10 μM.     

微米铜丝的低温力学性能测试

针对纤维材料变温环境力学性能测试的需要,在华中科技大学研制的纤维材料试验机的基础上引入了温控装置,从而实现纤维材料在高低温环境下的力学性能测试。采用该装置对不同直径微米铜丝在不同温度、不同拉伸速率条件下的力学性能开展实验研究,测试结果表明弹性模量和抗拉强度随温度的降低而线性增加,屈服强度的变化不太明显。另外,低温环境下微米铜丝的力学性能表现出与其直径相关的尺度效应,而这一现象在常温下一直没有观测到。最后,还研究了拉伸速率对微米铜丝的力学性能影响,结果表明,在现有装置的许用范围之内,拉伸速率对其力学性能的影响不大。     

A short and stereoselective synthesis of carbocyclic alpha-l-dideoxyhomonucleosides

A stereoselective five-step total synthesis of the hitherto unknown carbocyclic alpha-L-dideoxyhomonu-cleosides starting from readily available (1R,5S)-2-oxabicyclo[3.3.0]oct-6-en-3-one is described.     

An adaptive control scheme for a continuous plant under Known output delay, unmodelled dynamics, and input saturation

This paper deals with robustness of adaptive control of continuoussystems subject to known output delay, input saturation, unmodelledlinear dynamics, and bounded disturbances. A simple gradient-typealgorithm with a relative deadzone is used. The relative deadzoneis built with an estimated contribution of the unmodelled dynamicsto the system output. The basic tool used for stability androbustness analysis is Gronwall's lemma.     

Synthesis and anti-HIV activity of 5-haloethynyl and 5-(1,2-dihalo)vinyl analogues of AZT and FLT

In this paper, we report the synthesis of hitherto unknown 5-haloethynyl and 5-(1,2-dihalo)vinyluracil nucleoside analogues of the anti-HIV AZT, and FLT drugs. The key step of those syntheses is a Pd(0) cross-coupling at C5 position under Sonogashira conditions. Finally, based on their in vitro anti-HIV activities and their cytotoxicity on PBM, CEM, and VERO cell lines, the best compounds were the 2′,3′-dideoxy-3′-fluoro-5-(bromo-2-iodo)vinyluridine (10b, EC₅₀ of 0.6 μM), and the 3′-azido-2′,3′-dideoxy-5-(bromo-2-iodo)vinyluridine (16b, EC₅₀ of 1.1 μM).