三氯化铁-盐酸三乙胺离子液体催化异丁烯齐聚产物的组成分析

异丁烯在盐酸三乙胺-三氯化铁(Et3NHCl-FeCl3)室温离子液体催化作用下,选择性叠合成分子量较大的齐聚物,采用气相色谱/质谱(GC/MS)和气相色谱联用技术对异丁烯齐聚液相产物进行定性和定量分析。气相色谱毛细管色谱柱为PONA(50m×0.25mm,0.25μm),配FID检测器;质谱为EI源,离子源温度为250℃,色谱柱HP-5MS(30m×0.25mm×0.25μm),色谱条件为初始温度50℃(1.0min)8℃/min310℃,进样量0.2μL。结果表明液相产物的基本组成是异丁烯二聚体(碳八烯烃)、三聚体(碳十二烯烃)和四聚体(碳十六烯烃)的同分异构体,主要组分为短支链的异构烯烃,还有少量的烷烃和氯代烷烃。     

全二维液相色谱的初步构建及其在山羊血清分离中的应用

以GFC/RP模式构建全二维液相色谱系统,第一维凝胶过滤色谱柱使用ShodexProteinKW 802. 5(300mm×8mmi.d. ),以0. 2mol/LNaH2PO4 (pH7. 0)的流动相在0. 15mL/min的流速下等度洗脱,第二维反相色谱柱使用HypersilBDSC18 (35mm×4. 6mmi.d. ),在3mL/min的流速下梯度洗脱。采用平行柱交替分析的形式作切换接口, 2. 5min切换一次,两个反相柱交替富集、分析第一维洗脱产物。以5个标准蛋白混合物的分离评价该系统,在单独一维模式中不能分离的样品在全二维液相色谱中得到了较好的分离,二维系统的总峰容量为225。与一维色谱相比,系统的总峰容量、分辨率得到较大提高。并用于山羊血清的纯化分析,对一维分离中的重合谱峰进行验证,对制备纯化有一定的实际意义。     

二维液相色谱-质谱联用分离中药复方葛根芩连汤中的有效成分

建立了二维液相色谱-质谱联用方法分离中药复方葛根芩连汤的成分。以CN柱作第一维色谱柱,水和甲醇梯度洗脱分离;以ODS柱作第二维色谱柱,20 mmol/L乙酸铵缓冲液和乙腈梯度洗脱分离;质谱检测采用电喷雾电离/大气压化学电离（ESI/APCI）复合离子源,正负离子扫描。实验结果表明搭建的二维液相色谱的峰容量显著高于一维色谱,分离效率得到了明显的提高。以第一维色谱的第3个流分为例,对其二维分离进行仔细分析,发现质谱比紫外光谱检测到的组分多,质谱中采用负离子模式比正离子模式检测到的组分多。表明搭建的二维液相色谱-质谱分离平台分离效果好,提高了液相色谱的峰容量和分离效率。该方法操作简便,可作为中药等复杂体系分离分析的有效手段。     

对一种分离测定氨基酸方法的改进

 对Waters公司采用 6 氨基喹啉 N 羟基琥珀酰亚胺基 氨基甲酸酯 (AccQ Tag)柱前衍生化测定氨基酸的方法进行了改进。将流动相流速由原来的 1 0mL/min改变为 2 0mL/min ,用AccQ Tag专用柱 (3 9mmi.d .× 15 0mm ,4μm)在 17 5min(原为 35min) (运行周期为 2 2 5min ,原为 45min)内快速分离测定了 18种氨基酸和牛磺酸。用Nova PakC18柱 (3 9mmi.d .× 15 0mm ,4μm) ,Nova PakC18柱 (4 6mmi.d .× 15 0mm ,4μm) ,SymmetryC18柱 (3 9mmi.d .× 15 0mm ,4μm)和WatersXterraRP 18柱等反相C18柱代替AccQ Tag专用柱 ,均可对氨基酸进行快速分离。     

反相高效液相色谱法同时测定姜黄药材中3个组分的含量

建立了一种反相高效液相色谱方法,同时测定中药材姜黄块根中3组分的含量。采用KromasilTMC18柱(5μm,200mm×4.6mm),以磷酸水溶液(pH=2.5)和乙腈溶剂为流动相,梯度洗脱,流速0.9mL/min,柱温40℃,检测波长为425nm,10min内即可将3种组分分离测定。该方法快速、简便、准确,可为评价不同产地的姜黄质量提供依据。     

高效液相法同时检测南昌霉素和梅岭霉素

 采用高效液相法同时分离测定聚醚类抗生素南昌霉素和十六元大环内酯类抗生素梅岭霉素。柱为WatersXTerraTM RP18柱 (3 9mmi.d .× 15 0mm ,5 μm) ,流动相为乙腈水溶液 ,流速为 0 8mL/min ,其梯度洗脱程序为 5 7% (体积分数 ,下同 )乙腈 (30min)→ 70 %乙腈 (2min)→ 80 %乙腈 (2min)→ 90 %乙腈 (16min)。检测波长为 2 34nm ,柱温 2 5℃。该法测定的灵敏度好 ,加标回收率高 ,可用于南昌链霉菌发酵液中南昌霉素和梅岭霉素的定量测定。此法具有灵敏、准确、快速的特点。     

GC/MS和NMR分析5-氟-2-硝基苯乙醚还原反应的副产物

采用GC-MS分析5-氟-2-硝基苯乙醚的还原反应产物．在30．0m×250μmZB-5MS毛细管柱上,载气为He气,流量为0．8mL／min,起始柱温120℃维持3min,以20℃／min的速率升至260℃并维持10min,气化室温度270℃的条件下,5-氟-2-硝基苯乙醚还原的多种产物获得良好分离．通过对相应质谱图的解析,共鉴定出包括主产物在内的6种主要反应产物．经柱色谱分离提纯得到其中主要副产物,结合^1H-NMR确证该产物为未见报道过的副产物4-氟-2-氯-6-乙氧基苯胺．     

氮杂多环光致发光分子用于食品中脂肪胺的分析及质谱鉴定

对含氮类光致发光分子2-（11H-苯[a]咔唑）-异丙基氯甲酸酯进行柱前衍生处理,并经荧光检测对脂肪胺进行高效液相色谱（HPLC）分离和质谱定性。衍生物于λex=279nm产生强烈荧光,发射波长为λex=380nm。40℃下在pH9．0的硼酸缓冲液中,衍生反应3min后获得稳定的荧光产物。在Eclipse XDB-C8色谱柱（4．6mm×150mm,5μm）上,采用梯度洗脱对12种脂肪胺衍生物进行了优化分离。采用大气压化学电离源（APCI Source）正离子模式进行质谱定性,实现了各种脂肪胺衍生物的快速、准确测定。该方法具有良好的重复性,多数脂肪胺的线性回归系数大于0．9994,检出限在2．73～23．16fmol水平。     

反相高效液相色谱法测定大黄药材中游离及结合型蒽醌类衍生物的含量

建立了同时测定大黄药材中蒽醌类衍生物含量的RP HPLC法。色谱柱为HypersilC1 8柱 (2 5 0mm×4 6mmi.d .,1 0 μm) ,流动相为甲醇 乙腈 水 (3∶5∶2 ,磷酸调pH 2 .8) ,流速为 1 .0mL min ,柱温为 2 5℃ ,检测波长为 2 2 5nm。在此色谱条件下 ,各组分在 2 0min内均得到良好分离。平均回收率为 98.83 %～ 1 0 0 .9% ;相对标准偏差 0 .68%～ 1 .5 8%。     

二维超高效液相色谱-四极杆/飞行时间质谱法解析替考拉宁杂质

建立了二维超高效液相色谱-四极杆/飞行时间质谱法（2D-UPLC-Q/TOF-MS）对替考拉宁组分分离和杂质结构解析的分析方法,有效地解决了流动相中含不挥发性磷酸盐的色谱系统不适用于液相色谱-质谱快速鉴定替考拉宁杂质的难题。一维超高效液相色谱以Octadecyl silica （ODS） hypersil色谱柱（250 mm×4.6 mm, 5 μm）进行色谱分离,以3.0 g/L磷酸二氢钠溶液（pH 6.0）/乙腈=9/1 （v/v）为流动相A、3.0 g/L磷酸二氢钠溶液（pH 6.0）/乙腈=3/7 （v/v）为流动相B进行梯度洗脱;二维超高效液相色谱以Waters ACQUITY UPLC BEH C₁₈色谱柱（50 mm×2.1 mm, 1.7 μm）进行脱盐,以0.01 mol/L甲酸铵（pH 6.0）和乙腈为流动相进行梯度脱盐洗脱。质谱在电喷雾离子源、正离子模式下,采用全信息串联质谱（MS^E）模式采集质谱数据,锥孔气流速50 L/h,锥孔电压60 V,离子源温度120 ℃,雾化气流速900 L/h,雾化气温度500 ℃,毛细管电压2500 V,碰撞能量20~50 eV。根据杂质精确质量数及其二级质谱信息推导其结构,并对替考拉宁主要成分TA_2-2的裂解规律进行了推导,发现了2个母核特征离子;对《欧洲药典》10.0收录的10个组分及22个杂质组分进行二级质谱分析,发现了3个新杂质组分。采用该法既可以使用一维超高效液相色谱根据相对保留时间进行组分准确定位,也可以使用二维超高效液相色谱-四极杆/飞行时间质谱二级质谱信息快速、简便、灵敏地对杂质进行结构鉴定,为替考拉宁的质量控制和工艺优化提供了一种新思路。     

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.