两种色酮膦酸酯类化合物的合成及其结构表征

在超声波辐射下,以3-甲酰基色酮,对硝基苯胺和亚磷酸酯为原料,"一锅法"合成了两种含色酮环的α-氨基膦酸酯类化合物,通过IR,1H NMR,13C NMR,31P NMR,ESI-MS对其结构进行了测定和表征.对化合物4a进行了X射线衍射分析,O,O'-二乙基-α-对硝基苯氨基-α-(色酮-4-基)-甲基膦酸酯(4a)(CCDC:2080073)晶体属单斜晶系,C2/c空间群,晶胞参数为a=33.6146(11)(A),b=12.7607(4)(A),c=20.5344(4)(A),β=90.943(3)°,V=8806.9(4)(A)3,Z=16,C21H27N4O3P,Mr=432.36,Dc=1.304g· cm-3,μ=1.484,F(000)=3616,μ(CuKα)=1.54184 mm-1.     

α-氟-β-氨基酸酯的合成

采用简易方法从取代苯乙酮出发制得α-氟-β-脱氢氨基酸酯;在N,N-二甲基甲酰胺存在下用三氯硅烷将其还原,高收率和非对映选择性地合成了α-氟-β-氨基酸酯,其结构经1H NMR,13C NMR和MS确证。     

微波促进立体选择性高效合成糖基α,β-不饱和酯类化合物

利用微波促进糖醛与叶立德(Ph3P=CHCOOEt)发生Wittig反应,立体选择性地合成了含有α,β-不饱和酯的糖烯类化合物,反应效率显著提高,使用不同的反应溶剂可实现对反应立体选择性的控制.并通过1H NMR中双键氢的偶合常数确定了产物的构型.     

(S)-N-Boc-α-氨基庚(辛)二酸单酯和双酯的制备

以(S)-N-Boc焦谷氨酸乙酯为原料, 经DIBAL-H还原得到半缩醛, 然后经Wittig反应得到相应的烯烃, 最后氢化制得(S)-N-Boc-α-氨基庚二酸二(单)酯, 总收率为85.1%(二酯)和86.1%(单酯). 另外, 以(S)-N-Boc-哌啶-2-甲酸为原料经酯化和氧化得内酰胺, 然后经还原、Wittig反应、氢化得到(S)-N-Boc-α-氨基辛二酸二(单)酯, 总收率为72.5%(二酯)和72.4%(单酯). 产品用¹H NMR, MS表征.     

Synthesis,biological evaluation and molecular docking studies of novel benzimidazole derivatives

A novel series of N-substituted-benzimidazolyl linked para substituted benzylidene based molecules containing three pharmacologically potent hydrogen bonding parts namely; 2,4-thiazolidinedione (TZD: a 2,4-dicarbonyl), diethyl malonate (DEM: a 1,3-diester and an isooxazolidinedione analog) and methyl acetoacetate (MAA: a β-ketoester) (6a–11b) were synthesized and evaluated for in vitro α-glucosidase inhibition. The structure of the novel synthesized compounds was confirmed through the spectral studies (LC–MS, ¹H NMR, ¹³C NMR, FT-IR). Comparative evaluation of these compounds revealed that the compound 9b showed maximum inhibitory potential against α-amylase and α-glucosidase giving an IC₅₀ value of 0.54 ± 0.01 μM. Furthermore, binding affinities in terms of G score values and hydrogen bond interactions between all the synthesized compounds and the AA residues in the active site of the protein (PDB code: 3TOP) to that of Acarbose (standard drug) were explored with the help of molecular docking studies. Compound 9b was considered as promising candidate of this series.     

Alpha decay chains from superheavy nuclei

Magic islands for extra-stable nuclei in the midst of the sea of fission-instability were predicted to be around Z=114, 124 or, 126 with N=184, and Z=120, with N=172. Whether these fission-survived superheavy nuclei with high Z and N would live long enough for detection or, undergo α-decay in a very short time, remains an open question. α-decay half lives of nuclei with 130≥Z≥100 have been calculated in a WKB framework using density-dependent M3Y interaction with Q-values from different mass formulae. The results are in excellent agreement with the experimental data. Fission survived Sg nuclei with Z=106, N=162 is predicted to have the highest α-decay half life (∼3.2 h) in the Z=106-108, N=160-164 region called small island/peninsula. Superheavy nuclei with Z>118 are found to have α-decay half lives of the order of microseconds or less.     

由a-萘乙酸构筑的锌配合物的合成、晶体结构和性质研究

利用溶剂自然挥发法合成了一个新的单核配合物[Zn (α-NAA)2(H2O)2](HNAA=α-naphthylacetic acid),利用单晶X-射线衍射,粉末衍射仪,元素分析,红外光谱对其进行表征.结果表明该单晶属于单斜晶系Cc空间群,a=3.4607(4) nm,b=0.5509 (7) nm,c =1.1027(13) nm,β=106.8830(10)°,R(int) =0.057.同时,对配合物的热重性质和固体荧光性质进行了研究,CCDC 1053260.     

光电跟踪伺服系统中光纤陀螺滤波算法的应用

光纤陀螺作为光电跟踪伺服系统速度稳定回路的反馈测量元件,它的输出噪声直接影响伺服系统低速跟踪情况下的控制精度。抑制陀螺的输出噪声是改善伺服系统低速特性的有效手段之一。采用了一种简化的卡尔曼α-β滤波算法,使伺服系统的低速精度指标由原来采用移动平均滤波的0．0052°／s提高到0．0026°／s。实验证明,该算法可以有效地改善伺服系统的跟踪特性。     

Synthesis and Crystal Structure of 2-Benzylsulfnyl-3-cyano-5,7-dimethyl-pyrazolo[1,5-a]pyrimidine

The title compound, C16H14N4S, has been synthesized by the reaction of pentane-2,4-dione with 5-amino-3-benzylthio-4-cyano-l-H-pyrazole in ethanol, and its crystal structure was determined by X-ray diffraction method. The crystal is of monoclinic, space group P21/n with a=8.699(3), b=23.139(9), c=7.536(3) A, β= 92.400(8)°, V= 1515.5(10) A3, Z=4,Mr=294037, Dc= 1.290 g/cm3, λ=0.71073 A,μ(MoKo)=0.212 mm-1 and F(000)=616. The structure was refined to R=0.0533 and wR=0.1141 for 2672 unique reflections with Rint= 0.06.distance of 3.875 A and the angle of 164.8°.     

Efficient solid-phase synthesis of cyclic RGD peptides under controlled microwave heating

Cyclic RGD peptides are potent antagonists for the α_vβ₃ integrin receptor. In this Letter, microwave-assisted solid-phase synthesis of cyclic RGD peptides is described. In a coupling reaction between Fmoc-Arg(Pbf)-OH and high-loading H-Gly-Trt(2-Cl) resin, multiple coupling reactions were required for completion under the conventional HBTU activation. We found that the use of COMU, a new coupling reagent, under microwave heating to 50 °C accelerated the reaction even inside the resin. This method was applicable to the synthesis of linear pentapeptides, H-Asp(OtBu)-Xxx-Yyy-Arg(Pbf)-Gly-OH (Xxx = d-Phe(p-Br) or d-Tyr, Yyy = Lys(Boc) or MeVal). Cyclization of these peptides followed by deprotection gave the desired cyclic RGD peptides with high purity.