群柱内酯萜二维核磁共振谱的研究

本文研究了群柱内酯萜(Ⅰ)的二维¹H同核COSY、C-H COSY、远距C-H COSY谱,根据这些信息和经验规律归属了(Ⅰ)的¹H及¹³C谱峰,二维远距C-H COSY提供了相隔两、三个键的C-H偶合信息,因此,在很多方面可以代替灵敏度很低的INADEQUATE技术,得到C-C联结的信息。     

降压活性成分淫羊藿甙的HMQC和HMBC谱研究

首次对中药淫羊藿中降压活性成分淫羊藿甙的HMQC和HMBC谱进行了深入研究,结合¹H-¹H COSY谱,确切归属了全部碳氢信号,并直接从HMBC谱上确认了异戊烯基,甲氧基,鼠李糖和葡萄糖在黄酮母核上的连接位置,并修正了文献中关于该化合物某些碳信号归属的错误.显示这两种2D NMR新技术对结构复杂的黄酮甙类化合物的结构研究具有重要意义.     

DBU与全氟炔酸酯的迈克尔型加成及其产物的NMR谱学研究

1，8-二氮杂二环[5，4，0]十一碳-7-烯(DBU)与全氟炔酸酯反应生成成环化合物. 通过对成环产物的¹H NMR、¹H-¹H COSY、¹³C NMR和¹H-¹³C COSY的分析，归属了各NMR谱线，对相关化合物进行了结构确证，同时对反应机理进行了推测.     

双氢埃托啡的二维核磁共振研究

双氢埃托啡(1)为合成的新型高效镇痛药.其~1H和~(13)C NMR谱较为复杂,本文采用二维~1H—~1H COSY—NO ESY和~(13)C—~1H COSY等技术作了研究,确定了其全部~1H和~(13)C谱峰的归属,推断出C—7的构型,并且发现前人对其类似物的一些谱峰指定有误.本结果有助于此类化合物的结构测定和立体化学的研究.     

β-萘黄酮和β-二氢萘黄酮类化合物的13C-NMR研究

本文研究了14种β-萘黄酮和β-二氢萘黄酮类化合物的¹³C化学位移,发现其变化规律和单黄酮无大差异。通过COSY,HETCOR,HETCOLOC等2D-NMR谱和PBB,DEPT,QUAT,SELDEPT等碳谱实验指定了它们的碳的全部归属。     

南中国海海藻刺状鱼栖苔的化学成分研究(I)

从采自南中国海红藻刺状鱼栖苔的乙醇提取物中分离出一个黄酮类化合物,经IR,UV,FABMS,¹H-¹H COSY,¹³C-¹H COSY,HMBC等现代波谱技术确定其结构为5,7-二羟基-2-对羟基苯基-3-O-(6-O-对羟基肉桂酰基-β-D-吡喃葡萄糖基)-4H-1-苯并吡喃-4-酮,并对碳信号进行了明确归属.这是首次从红藻中分离出黄酮类化合物.     

嘧螨酯波谱学数据全归属

嘧螨酯为一种新型杀螨剂和STAT₃激活抑制剂. 该文对嘧螨酯的紫外吸收光谱(UV)、红外吸收光谱(IR)、质谱(MS)、核磁共振氢谱(¹H NMR)、核磁共振碳谱(¹³C NMR)、DEPT谱、¹H-¹H COSY谱、异核单量子相关谱(HSQC)、异核多键相关谱(HMBC)进行了解析,并对该化合物所有的核磁信号进行了全归属;同时讨论了紫外光谱吸收带位置和吸收强度与该化合物的生色团对应关系、红外光谱特征吸收峰与该化合物的各官能团的对应关系、氟原子(F)对其¹³C NMR的影响以及质谱离子碎片的归属和化合物的裂解规律. 该研究将为嘧螨酯的结构确证及其他相关研究提供参考.     

盐酸雷诺希芬的核磁共振谱研究

盐酸雷诺希芬是一种用于治疗骨质疏松症的药物，文中采用多种核磁共振技术，特别是¹H-¹H COSY、HMQC、HMBC等2D NMR技术，分别指认了其氢谱和碳谱的各个信号，对它的结构进行了分析.     

2-甲基-6-(2-甲苯基)-2-庚烯的波谱学研究

采用色谱法从蒲儿根花部位中分离得到2-甲基-6-(2-甲苯基)-2-庚烯,该化合物第一次以单体的形式得到,通过测定氢-氢相关谱(1H-1H COSY)、DEPT谱、异核单量子相关谱(HSQC)及异核多键相关谱(HMBC)等二维谱确定了该化合物的结构,并对该化合物的1H NMR和13C NMR谱进行了归属.     

癌基因MDM2阻断剂的分子结构的NMR研究

根据P53-MDM2复合物晶体结构,设计合成了非肽类小分子作为MDM2的阻断剂.利用超导核磁共振波谱仪,测定了化合物的¹H谱、¹³C谱、¹H-¹H COSY谱、HMQC和HMBC谱,确定了化合物的结构,归属了化合物的¹H、¹³C化学位移,为筛选抗癌活性化合物提供了理论依据.     

One-pot synthesis of 4-arylquinolines from aromatic aminoketones and vinylphosphonium salts

The addition of acetylenic esters to aromatic amines such as 2-amino benzophenone derivatives in the presence of triphenylphosphine leads to highly functionalized phosphoranes, which undergo an intramolecular Wittig reaction following oxidation to produce quinoline derivatives.     

Transition metal catalyzed manipulation of non-polar carbon-hydrogen bonds for synthetic purpose

The direct addition of ortho C-H bonds in various aromatic compounds such as ketones, esters, imines, imidates, nitriles, and aldehydes to olefins and acetylenes can be achieved with the aid of transition metal catalysts. The ruthenium catalyzed reaction is usually highly efficient and useful as a general synthetic method. The coordination to the metal center by a heteroatom in a directing group such as carbonyl and imino groups in aromatic compounds is the key step in this process. Mechanistically, the reductive elimination to form a C-C bond is the rate-determining step, while the C-H bond cleavage step is not. (Communicated by Ryoji NoyorI, M.J.A.).     

Ultrasound promoted ZrCl(4) catalyzed rapid synthesis of substituted 1,2,3,4-tetrahydropyrimidine-2-ones in solvent or dry media

Sonication of aromatic aldehydes, urea and ethyl acetoacetate in presence of solvent (ethyl alcohol) or solvent-less dry media (bentonite clay) supported-zirconium (IV) chloride (ZrCl(4)) as catalyst at 35 kHz gives 6-methyl-4-substitutedphenyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylic acid ethyl esters proficiently in high yields.     

Sonoluminescence intensity and ultrasonic cavitation temperature in organic solvents: Effects of generated radicals

Ultrasonic cavitation in organic solvents remains poorly understood in contrast with aqueous systems, largely because of complexities related to solvent decomposition. In this study, we sonicated different types of organic solvents (i.e. linear alkanes, aliphatic alcohols, aromatic alcohols, and acetate esters) under argon saturation. The average temperature of the cavitation bubbles was estimated using the methyl radical recombination method. We also discuss the effects of the physical properties of the solvents, such as vapor pressure and viscosity, on the cavitation temperature. The average cavitation bubble temperature and sonoluminescence intensity were higher in organic solvents with lower vapor pressure; for aromatic alcohols, these values were particularly high. It was found that the specific high sonoluminescence intensities and average cavitation temperatures exhibited in aromatic alcohols are caused by the highly resonance-stable generated radicals. The results obtained in this study are very useful for acceleration of sonochemical reaction in organic solvents, which are indispensable for organic synthesis and material synthesis.     

Fluorous parallel synthesis of a hydantoin/thiohydantoin library

Fluorous tagging strategy is applied to solution-phase parallel synthesis of a library containing hydantoin and thiohydantoin analogs. Two perfluoroalkyl (Rf)-tagged -amino esters each react with six aromatic aldehydes under reductive amination conditions. Twelve amino esters then each react with 10 isocyanates and isothiocyanates in parallel. The resulting 120 ureas and thioureas undergo spontaneous cyclization to form the corresponding hydantoins and thiohydantoins. The intermediate and final product purifications are performed with solid-phase extraction (SPE) over FluoroFlash^TM cartridges, no chromatography is required. Using standard instruments and straightforward SPE technique, one chemist accomplished the 120-member library synthesis in less than five working days, including starting material synthesis and product analysis.     

热解和生物降解对木本泥炭生烃与结构演化的红外光谱响应

傅里叶变换红外光谱分析物质分子结构具有独特的优势。为认识成煤有机质在微生物降解和热解阶段的生烃演化特征及物质结构变化特征,采用密封体系生烃热解和厌氧微生物降解岩样生烃物理模拟实验及傅里叶变换红外光谱分析等技术手段,研究了成煤母质(木本泥炭)的生烃演化特征(包括热解作用生成热成因气和微生物降解作用生成生物成因气的生烃潜力)及发生微生物降解和热解作用前后样品的分子结构变化特征及其机理。结果表明随模拟温度的升高,热解气烃类气体(主要为CH₄)累计产率逐渐增加,非烃类气体(如CO₂)分别在250和375 ℃出现两个产气高峰;随煤岩镜质组反射率的升高,微生物对其降解能力逐渐减弱;镜质组反射率介于1.6%～1.8%的泥炭热解样没有气体产出;泥炭经热解作用后,羟基含量随热解温度的升高先减少后增多,醛羰基、亚甲基和磷酸根的含量降低,芳香酸酯呈不单一减少趋势,伸缩振动S—O键在350 ℃之后的样品中出现且含量逐渐增加,说明其对微生物降解具抑制作用;泥炭经微生物降解作用后,酚、醇羟基、醛羰基、芳香酸酯、亚甲基和磷酸根的相对含量都大幅下降,且这些基团的分子间作用力相对减弱。     

Cerium ammonium nitrate (CAN)-catalyzed four-component one-pot synthesis of multi-substituted pyrano[2,3-\varvec{c}]pyrazoles under ultrasound irradiation

A convenient and efficient synthesis of multi-substituted dihydropyrano[2,3-c]pyrazole derivatives is reported. The four-component reaction of 4-hydrazinobenzoic acid, $\beta $ -keto esters, aromatic aldehydes, and malononitrile using 10 mol% CAN catalyst in water under ultrasound irradiation produced the target compounds in good-to-excellent yields. This method has advantages over conventional methods in being economic, non-toxic, and environmentally compatible due to its use of efficient and eco-friendly CAN catalyst and water solvent.     

顶空固相微萃取-气相色谱-质谱法分析扶芳藤叶挥发性成分

采用顶空固相微萃取-气相色谱-质谱法分析了扶芳藤叶挥发性成分,鉴定了90种化合物,主要挥发成分及其含量为:萜类(25种,45.82%)、酯类(20种,18.26%)、脂肪烃(20种,15.06%)、芳烃化合物(3种,7.31%)、酸酐(1种,4.91%)、酮类(4种,4.2%)、卤代烃类(7种,1.52%),为进一步开发和利用扶芳藤提供基础数据。     

石斛属植物中石斛碱类成分的波谱学特征

石斛属（Dendrobium Sw.）植物中的石斛碱类（dendrobines）倍半萜生物碱（sesquiterpenoid alkaloids）以其独特的结构和显著的生理活性而受到广泛关注．本文对石斛碱类化合物的结构特点及波谱学特征，包括紫外光谱（UV）、红外光谱（IR）、质谱（MS）、核磁共振（NMR）波谱等进行总结，并归纳石斛碱类成分的结构解析方式，为其深入研究与开发提供参考依据．     

Conformational Analysis of Longifolene

We describe the stable conformation of the tricyclic sesquiterpenoid, longifolene, by experimental NMR data and molecular mechanics calculations of the coupling constants. The flexible seven-membered ring of longifolene adopts a twist-chair conformation. Analysis of the coupling constants, particularly of the methylene protons in the cycloheptane ring moiety, agrees with this low-energy conformation. Low-temperature NMR experiments and nuclear Overhauser effect measurements indicate that there is a single exchange-averaged NMR spectrum that has the highest population of the most stable conformer.