傅里叶变换红外光谱法检测脑肿瘤

应用傅里叶变换红外光谱法检测了28例液氮冻存的离体脑肿瘤样本及其残留物(将脑肿瘤样本从ATR的ZnSe晶片上取下,样本在ZnSe晶片上沾染后留下的物质).结果发现,神经鞘瘤和神经上皮组织肿瘤(如星形细胞瘤等)的主要特征吸收峰存在明显差异,因此可从各个特征吸收峰的峰位、峰形及不同谱峰强度比的变化来初步鉴别脑肿瘤的性质,脑肿瘤组织样品残留物的红外光谱也可反映不同性质脑肿瘤的差异.与脂类糖蛋白以及核酸相关的谱带变化分析表明,通过特征峰强比(I1460cm-1/I1400cm-1,I1160cm-1/I1120cm-1和I1160cm-1/I1080cm-1)来鉴别肿瘤的性质与病理诊断结果的符合率超过85%.     

傅里叶变换中红外光纤光谱法用于腮腺肿瘤的检测

采用红外光谱仪与中红外光纤、衰减全反射(ATR)探头联用对40例腮腺肿瘤患者的腺体体表皮肤进行了测定, 并以病人术后肿瘤标本病理观察结果为判断标准, 对良性及恶性肿瘤光谱进行了判别, 发现光谱法判别结果与病理诊断结果基本一致. 实验结果表明, 正常腮腺、良性和恶性腮腺肿瘤体表皮肤的FTIR 光谱中存在显著的差异, 用相关吸收峰的峰形、峰位和峰强可以表征这些差异. 研究进一步发现, 对于不同类型的恶性肿瘤, 其体表组织的红外光谱主要差别在于1500—1000 cm-1区域内峰形及峰位的改变. 根据这一区域的差异可以将恶性肿瘤分为两大类: 一类恶性肿瘤具有上述的光谱特征(如腺泡细胞癌、嗜酸细胞腺癌和腺样囊性癌等), 另一类恶性肿瘤因为类型的不同在1500—1000 cm-1区域内峰形及峰位发生了很大的变化, 不同于上述的光谱特征.     

傅里叶变换中红外光谱法检测脑胶质瘤

采用傅里叶变换衰减全反射中红外光谱法检测了19例液氮冻存的脑胶质瘤离体组织样品(星形细胞瘤10例, 少枝-星形细胞瘤9例), 对得到的红外光谱进行分析发现, 恶性程度不同的星形细胞瘤组织的红外光谱存在差异, 并且不同类型的脑胶质瘤组织的红外光谱也表现出较为明显的区别, 因此可以根据各个特征吸收峰的峰位、 峰形及谱峰强度等信息来区分脑胶质瘤, 并初步鉴别脑胶质瘤的性质. 研究结果表明, 通过某些特征吸收峰峰位的变化来鉴别星形细胞瘤和少枝-星形细胞瘤与病理诊断结果的符合率约为80%, 说明傅里叶变换衰减全反射中红外光谱法有望发展成为一种对样品无损伤、 快速的脑肿瘤诊断新方法.     

丁基黄药在CuO表面吸附的二维连续在线原位ATR-FTIR光谱研究

运用连续在线原位衰减全反射傅里叶变换红外光谱(ATR-FTIR)技术测定了纳米CuO表面对丁基黄药的吸附行为.在FTIR谱图中发现有峰的红移现象,吸收峰由1200 cm-1偏移到1193 cm-1,用超纯去离子水脱附,峰强度只有微小的变化,可判断丁基黄药在CuO表面发生了很强的化学吸附.通过对吸附行为进行二维(2D)红外光谱分析,分辨出吸附过程中光谱强度的变化顺序.二维异步相关光谱测定结果表明,1265 cm-1处振动吸收峰最先引起光谱强度的变化,1265 cm-1处吸收峰可归因为表面反应生成的双黄药和黄药分子聚集体的复合峰.根据1200 cm-1处黄药特征吸收峰强度的变化,进行吸附动力学模拟,得出CuO对丁基黄药的最大吸附量为529 mg·g-1,且吸附符合拟二级吸附动力学过程.     

线型低密度聚乙烯的快速鉴定

采用对样品进行液氮淬火及溴化处理的制样方法,以期达到消除分子晶体场及分子链烯类端基对分析谱带的影响和干扰,结果表明:(1) 1 378 cm-1甲基对称变形振动谱带强而尖锐,和1 368 cm-1亚甲基面外摇摆振动谱带清晰分开,表明分子链上只存在一种单一的支链;(2)890 cm-1附近不存在表征长支链的甲基面内摇摆振动峰,只有772 cm-1附近存在表征乙基支链的亚甲基面内摇摆振动峰.成功地鉴定了以1-丁烯为共聚单体的线型低密度聚乙烯,方法简便、快速,为鉴定其他类的以烯烃为共聚单体的线型低密度聚乙烯(LLDPE)提供了重要思路.     

傅里叶变换红外光谱法识别分析四种天然皮革材质

以国家部分标准皮革样品及市售皮革样品等天然皮革为样品,采用傅里叶变换红外光谱仪的衰减全反射附件--OMNI采样器,收集傅里叶变换红外吸收光谱,对光谱预处理后,提取红外光谱的特征信息,以2 925 cm-1和2 854 cm-1处的吸收峰面积比值为横坐标,1652 cm-1与1 552 cm-1处的吸收峰面积比为纵坐标,用Origin 7.0化学化工制图软件绘制二维分布图,对各种皮革样品进行识别分析.结果显示:猪皮革、牛皮革、马皮革的样品点分布效果好,而羊皮革的各样品点之间比较分散;猪皮革样品点明显区别于牛皮革、羊皮革和马皮革,马皮革样品点明显区别于牛皮革、羊皮革和猪皮革,而牛皮革和羊皮革的样品点分布有交叉.     

二维红外光谱法分析纤维素

采用二维红外光谱法分析纤维素。在293~393K范围内,分别测定脱脂棉纤维的一维红外光谱、二阶导数红外光谱和去卷积红外光谱。结果表明:脱脂棉纤维中的α-纤维素在559cm-1有一个的红外特征吸收峰,β-纤维素在893,1 206,1 235cm-1处有红外特征吸收峰;随测定温度的升高,559cm-1处红外吸收强度降低,893,1 206,1 235cm-1处红外吸收强度增加。进一步采用二维红外光谱研究温度对于脱脂棉纤维结构的影响,结果表明:随测定温度的升高,脱脂棉纤维红外特征吸收峰强度增加的顺序为893cm-11 235cm-11 206cm-1559cm-1。     

漫反射傅里叶变换红外光谱法测定制剂中左氧氟沙星

采用新型的制样方法,利用漫反射傅里叶变换红外光谱(DRIFTS)法测定了左氧氟沙星制剂中左氧氟沙星的含量。选择1620 cm-1处的酮羰基伸缩振动吸收峰作为定量分析峰,以1580~1655 cm-1范围内的峰面积评估吸光度,吸光度与左氧氟沙星质量分数在0.20%~1.20%范围内呈良好的线性关系,相关系数为0.984,相对标准偏差(RSD)≤5.6%。新型制样方法可使样品与KBr基质混合更均匀,有效消除镜面反射光及排除辅料中不可溶淀粉对分析测定的干扰,提高分析结果的精密度和准确度;以含可溶性淀粉的左氧氟沙星标准样品绘制标准工作曲线可以消除少量可溶性淀粉对分析测定的干扰。DRIFTS法测定了3种市售制剂中左氧氟沙星含量,结果与紫外分光光度(UV)法基本一致。     

红外光谱法对六氟磷酸锂的快速定量分析

本文建立了一种用傅里叶红外光谱(FT-IR)法快速定量分析LiPF6的方法。采用红外光谱(IR)法和X射线衍射(XRD)法对LiPF6样品进行了定性分析。选取LiPF6红外光谱847cm-1处的特征吸收峰为分析对象,利用吸光度峰面积积分法进行定量分析,由标准曲线可知,LiPF6的含量与其红外光谱特征峰的吸收强度有很好的线性关系,相关系数达0.9998,线性范围在0.04～25mg.mL-1,检出限可达0.02mg.mL-1。LiPF6样品定量测定的相对标准偏差(RSD)约为0.18%,回收率为96%～98%。     

胆酸和脱氧胆酸分子的远红外与THz吸收光谱研究

胆酸和脱氧胆酸是胆汁酸中的主要成分, 是人体中重要的生物表面活性剂. 两种分子只相差一个羟基, 在远红外和太赫兹波段有不同的吸收光谱. 胆酸分子的太赫兹(THz)吸收光谱有1.26 THz(42 cm-1)和2.02 THz(67 cm-1)两个吸收峰, 脱氧胆酸分子的THz吸收光谱有1.13, 1.26, 1.69和2.17 THz(即38, 42, 56, 72 cm-1)等几个吸收峰. 两个分子的THz吸收光谱都包含有1.26 THz(42 cm-1) 峰, 反映出二者结构的相似性. 它们的远红外光谱都有部分频率相近的谱带, 但对比之下可以观察到峰位位移和相对峰强的改变. 指认了两种物质的某些可能与羧基振动有关的特征吸收峰. 为找出THz光谱隐含的信息, 利用Omnic程序采用二阶导数方法来处理THz光谱数据, 观察到多个子峰, 说明分子结构中可能存在更复杂的氢键状态. 实验结果表明, 远红外和THz吸收光谱是研究生物分子及鉴别生物分子结构的很好方法.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.