三梅片成份分析研究

医药品冰片有天然品与合成品之分,天然品有:由龙脑香科(Dipterocarpaceae)植物龙脑香(Dryobalanops aromatica G aertn,f.)制得的结晶,称龙脑香冰片;白菊科(Compositae)植物艾纳香(Blumea balsamifera DC.)所得的结晶,名艾片。艾片因其晶形似梅花片,又有梅片之称,根据梅花片状又分为大梅片,二梅片,三梅片,天然品化学成分为龙脑(Borneol,Ⅰ),合成冰片(又名合成龙脑),除含龙脑外尚含较大量的异龙脑(ISO-borneol,Ⅱ)     

通过与香草醛的显色反应检测冰片成分

冰片样品及纯冰片标准样用无水乙醇为溶剂,利用香草醛在浓硫酸中与龙脑及异龙脑的显色反应,用分光光度法测定冰片含量,测定波长为470 nm.在优化条件下,吸光度与龙脑浓度之间在0.06～0.30 g·L-1范围内呈线性关系,对应于线性回归方程A=2.850 1 C 0.015 6,相关系数为0.999 3;测得三批冰片样品中龙脑质量浓度分别为0.093,0.097,0.096 g·L-1.在同一试样中加入3种不同浓度的龙脑标准溶液按试验方法进行回收试验,测得回收率在93.3%～98.5%之间.     

毛细管气相色谱法测定驱风苏合丸中冰片的含量

用毛细管气相色谱内标法，不经分离直接测定中成药驱风苏合丸中冰片的含量，有良好的线性关系，相关系数为０．９９９９，７次分析的相对标准偏差，对于异龙脑为０．１３％，对于龙脑为０．３４％。样品处理简单、合理，使用本法于实际样品分析，获得了满意的结果。     

合成龙脑与合成樟脑制备新工艺初探

报道了一种制备合成龙脑与合成樟脑的新工艺。常压下异龙脑在一种含锌催化剂作用下 ,可部分脱氢生成樟脑 ,部分异构化生成龙脑。将此产物分离提纯后可同时得到合成樟脑与合成龙脑     

电子烟烟液中烟碱旋光异构体的手性液相色谱分离及测定

建立了手性色谱柱-液相色谱-二极管阵列检测器(HPLC-DAD)法测定电子烟烟液中烟碱旋光异构体,即左旋烟碱(S-(-)-烟碱)和右旋烟碱(R-(+)-烟碱),对分析方法进行了优化和表征。结果表明:(1)最优的色谱条件为:采用大赛璐手性柱CHIRALPAK-IC,流动相为正己烷/异丙醇(体积比为95:5,含0. 1%二乙胺),流速1. 0 m L·min-1,等度洗脱。在优选条件下,电子烟烟液中左旋烟碱和右旋烟碱能实现基线分离,分析时间仅需18 min;(2)左旋烟碱和右旋烟碱分别在15～700μg·m L-1、0. 75～30μg·m L-1浓度范围内线性关系良好,二者检出限均为0. 02 mg·g-1。本方法左旋烟碱的日内、日间精密度分别为0. 73%、1. 67%,右旋烟碱的日内、日间精密度分别为4. 50%、8. 60%;二者回收率的结果在95. 50%～104. 5%之间;(3)选取不同口味、不同焦油量的电子烟烟液样品67个,对烟碱旋光异构体分别进行测定,结果表明电子烟烟液中主要为左旋烟碱,右旋烟碱检出率仅为12%,其含量占总烟碱的比例为0. 41%～4. 55%;(4)选取电子烟烟液样品20个,采用所建立的方法测定电子烟烟液和对应的电子烟气溶胶中左旋烟碱和右旋烟碱的含量,结果表明含有右旋烟碱的电子烟烟液所对应的电子烟气溶胶中未检出右旋烟碱。     

气相色谱法测定冠心膏中樟脑、薄荷脑、异龙脑、龙脑的含量

用气相色谱法测定了冠心膏中樟脑、薄荷脑、异龙脑和龙脑的含量。固定相：７％ＰＥＧ－１５００,线性范围：５～４５０ｍｇ／Ｌ（ｒ＝０．９９９４～０．９９９９）。回收率：樟脑为９８．４４％,薄荷脑为９９．０１％,异龙脑为９９．６９％,龙脑为１０１．９％。     

硼酸酯化法分离龙脑、异龙脑与樟脑

用硼酸与异龙脑的异构化产物—龙脑、异龙脑和樟脑的混合物进行反应，得到硼酸莰酯和樟脑。莰酯与樟脑分离后，经水解得到龙脑和异龙脑。     

高效液相色谱法测定松节油深加工产物中松油醇含量

采用高效液相色谱法测定了松节油深加工产物中松油醇的含量,以Waters porasil硅胶柱为固定相,正己烷-乙酸乙酯(99+1)混合溶液为流动相,检测波长为238nm,外标法定量,在室温条件下分离α-松油醇的左旋、右旋异构体及其他组分,并且准确测定左旋α-松油醇及右旋α-松油醇含量.线性范围分别为0.61～11.20 g·L-1和0.8～13.0 g·L-1,回归方程分别为A=0.806+15.90 C,相关系数为0.999 8和A=0.108 6+17.63 C,相关系数为0.999 7,相对标准偏差分别为1.54%和1.06%,回收率分别为90%～112%和93%～112%.     

α-蒎烯水合主产物的分离与提纯

根据α-蒎烯水合产物中的龙脑、异龙脑和α-松油醇在邻苯二甲酸酐存在下发生酯化、脱水反应的选择性差异，可将三者大部分分离，提高优质龙脑和α-松油醇的得率。．     

气相色谱-傅里叶变换红外光谱技术应用于冠心苏合丸中挥发性成分分析

本文应用气相色谱-傅里叶变换红外光谱联用技术对中成药冠心苏合丸中挥发性成分进行了库检索,鉴定了其中7种有效成分,并采用内标法对其中龙脑、异龙脑的总量进行了含量测定,其平均回收率为98.53％.     

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.