20,20-二氯-1,10-二甲氧基三环[5,4,0,012,19]十一碳 -1,5,6-三烯结构和性质的理论研究

在RHF/6-31G、B3LYP/6-31G和MP2/6-31G水平下优化了标题化合物的平均几何构型,用B3LYP/6-31G方法计算了该化合物的红外光谱.并用GIAO分别在B3LYP/6-31G、B3LYP/6-311G和B3LYP/6-311++G水平对该化合物的核磁共振谱进行了研究.计算结果与实验结果吻合很好.同时对在合成过程中发现的两个中间产物进行了理论计算,研究证实了合成标题化合物时中间产物的存在.     

聚3-苯基噻吩的合成及其结构表征

用有机合成方法-格氏偶联法合成出了3-苯基噻吩及其聚合物;用红外光谱、紫外光谱、核磁共振光谱和元素分析等方法对标题化合物进行了表征,从红外谱图、紫外谱图、核磁共振谱,元素分析数据可以推测出所合成的化合物是聚3-苯基噻吩。     

2-(2-取代苯基丙烯基)-5-取代苯并唑的光性质研究

本文测试了２０个标题化合物的紫外光谱和荧光光谱，讨论了它们的取代基效应，研究了１６种溶剂对其中两个化合物的紫外光谱的溶剂效应以及一个化合物的光反应     

5-(4-吡啶基-1,3,4-(口恶)二唑-2-硫酮的合成和谱学研究

5-(4-吡啶基)-1,3,4-(口恶)唑-2-硫酮(C7H5N3OS)是异烟肼与二硫化碳发生加成闭环反应时获得.文章初步讨论了反应历程,提出该反应的机理是亲核加成,并通过IR谱和NMR谱对标题化合物的结构进行了表征,热稳定性测试表明:该化合物在506℃时完全分解.     

1,1-二甲硫基-[1]-烯基丙二酸二甲酯与苯相互作用的1H NMR研究

本文在四氯化碳介质中考察了苯对1,1-二甲硫基-[1]-烯基丙二酸二甲酯的溶剂效应,观察到标题化合物分子内的甲基和溶剂苯的化学位移随着苯的摩尔分数增加而逐渐移向高场,溶剂苯的共振吸收峰是一个尖锐的单峰,同时发现了标题化合物分子中甲基和溶剂苯的化学位移值与混合溶剂苯的摩尔分数呈线性关系.     

3,7-二硝基亚氨基-2,4-二氮杂双环[3,3,0]辛烷的放热分解反应动力学

在程序升温条件下 ,用DSC研究了标题化合物的放热分解反应动力学 .用线性最小二乘法、迭代法以及二分法与最小二乘法相结合的方法 ,以积分方程、微分方程和放热速率方程拟合DSC数据 .在逻辑选择建立了微分和积分机理函数的最可几一般表达式后 ,用放热速率方程得到相应的表观活化能 (Ea)、指前因子 (A)和反应级数 (n)的值 .结果表明 :该反应的微分形式的经验动力学模式函数、Ea 和A值分别为 (1-α) 0 .44、2 30 .4kJ/mol和 10 18.16s-1.借助加热速率和所得动力学参数值 ,提出了标题化合物放热分解反应的动力学方程 .该化合物的热爆炸临界温度为 30 2 .6℃ .上述动力学参数对分析、评价标题化合物的稳定性和热变化规律十分有用 .     

3-萘基-5-萘偶氮基-[1,3,4]-噻二唑-2-硫酮的合成及谱学研究

3-萘基-5-萘偶氮基-[1,3,4]-噻二唑-2-硫酮由二-α-萘基硫代卡巴腙与二硫化碳在碱性条件下发生加成闭环反应生成.文章研究了该反应的历程,提出该反应的机理是亲核加成,并通过IR谱、UV谱和NMR谱对标题化合物的结构进行了表征.     

5-乙氧羰基-4-取代-6-甲基-3,4-二氢嘧啶-2（1H）-酮的电子轰击飞行时间质谱表征

研究了一系列5-乙氧羰基-4-取代-6-甲基-3,4-二氢嘧啶-2(1H)-酮的电子轰击飞行时间质谱,建立了此类化合物的裂解方式和分子离子峰的强度规律.利用飞行时间质谱的中分辨能力,测得了各碎片离子的精确质量,这些数据经OpenLynx软件导出所有分子离子和碎片离子的元素组成.根据质谱裂解规律,主要质谱离子得到了归属.两类主要裂解途径为:对所有标题化合物,通过失去4位上的R1,酯基上的C2H4(麦氏重排)和H2O(通过环状六员过渡态)形成三种阳离子;对4-芳基化合物,通过失去EtCO2形成另一类阳离子.此外,还提出了个别化合物的一些重要裂解行为.     

5-(2-芳氧甲基苯并咪唑-1-亚甲基)-1,3,4噁二唑-2-硫酮的结构,光谱与热力学性质的理论研究

采用密度泛函理论B3LYP方法对标题化合物分子进行几何构型优化和频率计算,得到红外光谱和拉曼光谱及不同温度下的热力学性质.计算模拟分子在气相和不同溶剂下的电子吸收光谱.结果显示,分子内氢键的形成有利于分子稳定,并与实验晶体结构一致.气相中最大吸收峰出现在236nm处,属于近紫外区,溶剂作用使其蓝移(减小)20nm左右,且与溶剂极性无关.     

反式和顺式-1,2-二氰-(4-乙基苯)乙烯结构的谱学分析

合成了2种新型的可溶性四氮杂卟啉中间体:反式-1,2-二氰-(4-乙基苯)乙烯和顺式-1,2-二氰-(4-乙基苯)乙烯.通过UV-Vis,FTIR,GC/MS,1H NMR等方法对这2种化合物的结构进行了表征,给出了它们完整的结构信息.分析比较了顺、反异构体结构上的差异,分析两者的紫外-可见光谱(UV-Vis)、红外光谱(FTIR)和核磁共振光谱(1H NMR)谱图的差异及其产生原因.     

Perception of the [m]-[n] distinction in CV syllables

The contribution of the nasal murmur and the vocalic formant transitions to perception of the [m]-[n] distinction in utterance-initial position preceding [i,a,u] was investigated, extending the recent work of Kurowski and Blumstein [J. Acoust. Soc. Am. 76, 383-390 (1984)]. A variety of waveform-editing procedures were applied to syllables produced by six different talkers. Listeners' judgments of the edited stimuli confirmed that the nasal murmur makes a significant contribution to place of articulation perception. Murmur and transition information appeared to be integrated at a genuinely perceptual, not an abstract cognitive, level. This was particularly evident in [-i] context, where only the simultaneous presence of murmur and transition components permitted accurate place of articulation identification. The perceptual information seemed to be purely relational in this case. It also seemed to be context specific, since the spectral change from the murmur to the vowel onset did not follow an invariant pattern across front and back vowels.     

Perception of the [m]-[n] distinction in VC syllables

This study complements earlier experiments on the perception of the [m]-[n] distinction in CV syllables [B. H. Repp, J. Acoust. Soc. Am. 79, 1987-1999 (1986); B. H. Repp, J. Acoust. Soc. Am. 82, 1525-1538 (1987)]. Six talkers produced VC syllables consisting of [m] or [n] preceded by [i, a, u]. In listening experiments, these syllables were truncated from the beginning and/or from the end, or waveform portions surrounding the point of closure were replaced with noise, so as to map out the distribution of the place of articulation information for consonant perception. These manipulations revealed that the vocalic formant transitions alone conveyed about as much place of articulation information as did the nasal murmur alone, and both signal portions were about as informative in VC as in CV syllables. Nevertheless, full VC syllables were less accurately identified than full CV syllables, especially in female speech. The reason for this was hypothesized to be the relative absence of a salient spectral change between the vowel and the murmur in VC syllables. This hypothesis was supported by the relative ineffectiveness of two additional manipulations meant to disrupt the perception of relational spectral information (channel separation or temporal separation of vowel and murmur) and by subjects' poor identification scores for brief excerpts including the point of maximal spectral change. While, in CV syllables, the abrupt spectral change from the murmur to the vowel provides important additional place of articulation information, for VC syllables it seems as if the format transitions in the vowel and the murmur spectrum functioned as independent cues.     

1,2,4,6—四苯基—2—羟基—8—氮杂双环[3、2、1]辛烷的核磁共振研究

用多种核磁共振实验方法并结合其它结构信息,确定1,2,4,6-四苯基-2-羟基8-氮杂双环[3、2、1]辛烷的化学结构,并指定该化合物的核磁共振归属。     

Ground- and excited-state spectroscopic studies on [1-(4-methoxyphenyl)-3-(amino)-2,4-(dicyano)-9,10-tetrahydrophenanthrene]

The effects of polar and nonpolar solvents on both the ground and the excited-state properties of [1-(4-methoxyphenyl)-3-(amino)-2,4-(dicyano)-9,10-tetrahydrophenanthrene] is examined. Light absorption results in a population of a locally excited (LE) first singlet state (S₁,n^*) which shows sensitivity to the polarity of the surrounding solvent and hydrogen-bonding ability to the quencher 4-methylpyridine. Relaxation of this state leads to an intramolecular charge-transfer state (ICT) which leads to a large Stokes shift in polar solvents and an excited-state dipole moment of _e= 10D. The quenching of the fluorescence state by 4-methylpyridine studied inn-hexane and acetonitrile at room temperature is found to be efficient and a positive deviation from linearity was observed in the Stern-Volmer plots even at concentrations of 4-methylpyridine below 0.4M. This is explained as a result of the occurrence of both a dynamic and a static quenching mechanism. The static quenching constants (K _sv) along with those obtained by visible spectroscopy (K _GS) indicate that the ground-state complex is weak and relatively solvent dependent.     

[Z]-1-[三苄基锡基]-3-苯基-1-丁烯-3-醇的合成与谱学表征

本文合成了一种新的有机锡化合物 ,通过熔点测定、红外光谱、核磁共振谱、元素分析、锡含量测定等手段对其结构进行了表征.     

Calibration of the R ruby fluorescence lines in the pressure range [0-1 GPa] and the temperature range [250-300 K]

Abstract

The pressure range [&1 GPa] and the temperature range [250–300 K] are commonly used in many science fields like biology, agro-chemistry, pharmacology, or geology. In this paper, the calibration of the ruby R lines of fluorescence is performed in these pressure and temperature ranges, using the melting curve of pure water. The linear shifts of ruby peaks are equal to ?0.140cm^?1/K and ?0.768cm^?1/kbar with R₁, and to ?0.137cm^?1/K and ?0.779 cm^?1/kbar with R₂. The accuracy of pressure measurements can be as good as ± 10MPa if the temperature is known with ±0.5 K. Such a precision is achieved if: (1) the position of each peak is determined using an inversion method; (2) daily shifts of the spectrometer are corrected before each acquisition; (3) peak positions of each ruby are known at ambient pressure and temperature.     

(E)-3-[N-(α-苯乙胺)]-2-烯基-1-苯丙酮的合成及其研究

烯胺是一类重要的反应中间体,其在有机合成中有着广泛的应用.采用碳-氮转移法合成了结构稳定、不易转变为亚胺的手性烯胺化合物(E)-3-[N-(α-苯乙胺)]-2烯基-1-苯丙酮,并对产物进行了红外光谱及核磁共振氢分析,结果令人满意.     

Discovery of ( ±)-3-(1 H -pyrazol-1-yl)-6,7-dihydro-5 H -[1,2,4]triazolo[3,4- b ][1,3,4] thiadiazine derivatives with promising in vitro anticoronavirus and antitumoral activity

A new series of (?±)-(3-(3,5-dimethyl-1H-pyrazol-1-yl)-6-phenyl-6,7-dihydro-5H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazin-7-yl)(phenyl)methanones were efficiently synthesized starting from 4-amino-5-hydrazinyl-4H-1,2,4-triazole-3-thiol 1, acetyl acetone 2, various aromatic and heterocyclic aldehydes 3 and phenacyl bromides 4. All the newly synthesized compounds were tested for their antiviral and antitumoral activity. It was shown that subtle structural variations on the phenyl moiety allowed to tune biological properties toward antiviral or antitumoral activity. Mode-of-action studies revealed that the antitumoral activity was due to inhibition of tubulin polymerization.

Graphic abstract

     

Ultrasound promoted greener synthesis of spiro[indole-3,5′-[1,3]oxathiolanes in water

An aqueous mediated novel synthesis of substituted 2′amino-4′benzoyl-2′-methyl spiro[indole 3,5′-[1,3]oxathiolane]-2(1H)-ones (2a–f) was carried out from the reaction of spiro [indole-3,2′-oxiranes] (1a–f) with thioacetamide in the presence of LiBr as catalyst. The reaction was carried out under both microwaves and sonication and results were also compared with conventional method. In general, improvement in rate and yields observed when reaction was carried out under sonication as compared to microwave irradiation and conventional method.     

An asymmetric approach to the radiosynthesis of both enantiomers of α-[11C]methyldopa and α-[11C]methyltyrosine for positron emission tomography

In PET, α-methyl amino acids can play a dual role: a) precursors of neurotransmitters analogues for the study of neurodegenerative diseases; b) non-metabolised analogues of proteinogenic amino acids for the study of amino acids uptake into normal and cancer cells. The difference in the uptake rates during a PET scan could visualise cancer cells in a human body. Clinical applications of such amino acids are strongly limited due to their poor availability. For the synthesis of α-[¹¹C]methyl-tryptohan, an industrial procedure was adopted. All attempts to prepare enantiomerically pure α-[¹¹C]methylated tyrosine failed. We carried out [¹¹C]methylation of metalocomplex synthons derived from protected DOPA or tyrosine. Individual diastereomers were successfully separated by preparative HPLC, diluted with excess of water and extracted on C₁₈ cartridges. Optimisation of the procedure followed by hydrolysis of the complexes and purification of the enantiomers of α-[¹¹C]methylDOPA and α-[¹¹C]methyltyrosine is underway.