胶束增敏紫外分光光度法测定甲砜霉素的研究

用紫外分光光度法对pH 6.00Na2 HPO4-NaH2 PO4的缓冲介质中甲砜霉素和溴化十六烷基三甲铵( CTMAB)形成的胶束配合物的性能进行了研究.利用胶束的增敏增稳作用,提出了测定甲砜霉素的紫外分光光度新方法,方法线性范围为0.25～95 μg/mL,检出限为0.12 μg/mL.已应用于片剂中甲砜霉素的测定...     

溴甲酚绿与甲砜霉素的显色反应及应用

在pH 4.0～5.3的条件下,甲砜霉素与溴甲酚绿反应生成具有1个正吸收峰和2个几乎相等的负吸收峰的离子缔合物。最大正吸收波长位于610 nm,2个负吸收波长分别位于652 nm和574 nm,表观摩尔吸光系数分别为2.16×104 L.mol-1.cm-1(正吸收),1.36×104 L.mol-1.cm-1(652 nm负吸收)和1.32×104 L.mol-1.cm-1(574 nm负吸收),线性范围均为0～5.3 mg/L。甲砜霉素在一定浓度范围内遵从朗伯比尔定律,由此建立了测定甲砜霉素的正吸收、负吸收及双波长叠加吸收光谱法。方法已用于人体尿液、血液及市售药物中甲砜霉素含量的测定。     

高效液相色谱-串联质谱法同时测定水产品中氯霉素、甲砜霉素和氟甲砜霉素的残留量

建立了水产品中氯霉素、甲砜霉素和氟甲砜霉素药物残留量同时测定的高效液相色谱-串联质谱方法。以氘代氯霉素做内标,选择乙酸乙酯提取,HLB固相萃取柱净化,洗脱液氮气吹干,采用LC-MS/MS选择反应监测(SRM)负离子模式进行定性、定量分析。结果表明:氯霉素的检出限(LOD)为0.01μg/kg,甲砜霉素和氟甲砜霉素检出限(LOD)为0.03μg/kg,检测结果的相对标准偏差为3.3%～9.7%(n=6),加标回收率达到78.6%～110.5%。该方法在水产品中氯霉素、甲砜霉素和氟甲砜霉素药物的残留测定中具有很好的应用前景。     

曙红Y分光光度法测甲砜霉素的含量

甲砜霉素(TAP)与曙红Y(EOSY)在pH＝1.52的酸性介质中相互反应生成离子缔合物,可使体系吸光度增大.最大吸收波长位于482 nm,表观摩尔吸光系数(ε)为4.27×10 4 L·mol-1·cm-1,甲砜霉素浓度在0.18～5.3 mg·L-1范围内遵从比尔定律,据此建立了以曙红Y为探针测定甲砜霉素的分光光度法.该法简便快速,有较高灵敏度,可用于实际样品中甲砜霉素的测定.     

高效液相色谱/串联质谱法同时测定虾中氯霉素、甲砜霉素和氟甲砜霉素残留量

用高效液相色谱／串联质谱(LC／MS,／MS)同时测定虾中的氯霉素(CAP)、甲砜霉素(TAP)和氟甲砜霉素(FF)。均质后的虾样品,采用碱化乙酸乙酯提取。浓缩提取物经液．液分配(LLP)去除脂肪,C18固相萃取(SPE)柱净化后,采用LC／MS／MS电喷雾电离(ESI),负离子,多反应监测(MRM)模式检测,外标法定量。检出限为：氯霉素和氟甲砜霉素0．01ng/g;甲砜霉素为0．05ng／g。在添加浓度0．1～2．0ng/g范围内,氯霉素回收率为73．9％～96．0％;甲砜霉素回收率为78．6％～99．5％;氟甲砜霉素回收率为74．9％～103．7％;相对标准偏差(RSD)均小于6．4％。     

超高效液相色谱-串联质谱法测定畜禽副产品中氯霉素和氟甲砜霉素残留量

建立了超高效液相色谱-串联质谱测定畜禽副产品中氯霉素和氟甲砜霉素残留量的方法。样品经碱性乙酸乙酯提取,正己烷脱脂后,直接采用电喷雾电离(ESI)多反应监测(MRM)负离子模式检测,氯霉素用同位素内标定量,氟甲砜霉素用外标法定量。氯霉素和氟甲砜霉素在0.2～50μg/L范围内线性良好,相关系数达到0.9999;检出限均为0.04μg/kg;氯霉素回收率为89.6%～112.0%,RSD为5.4%～8.1%;氟甲砜霉素回收率为90.3%～110.0%,RSD为5.1%～8.0%。方法可用于畜禽副产品中氯霉素和氟甲砜霉素残留量测定。     

超高效液相色谱-串联质谱法测定禽蛋中氯霉素、甲砜霉素和氟甲砜霉素

采用超高效液相色谱-三重四极杆串联质谱,用多反应监测模式定量,建立了禽蛋中氯霉素、甲砜霉素和氟甲砜霉素同时测定的分析方法。添加氯霉素-d5作为内标进行定量,试样经过乙酸乙酯提取,三氯乙酸去蛋白,盐析,分离,再经正己烷去脂肪,省去固相萃取净化步骤,直接上机测定。氯霉素、甲砜霉素和氟甲砜霉素的检出限分别为0.03,0.03和0.015"g/kg,定量限分别为0.10,0.10和0.05"g/kg,3种化合物的加标平均回收率在90.5%~103.5%,相对标准偏差在2.1%~6.0%之间。方法能对禽蛋中的氯霉素类化合物进行检测分析。     

超高效液相色谱法测定水产品中甲砜霉素和氟甲砜霉素残留

建立了一种同时测定水产品中甲砜霉素和氟甲砜霉素药物残留的超高效液相色谱(UPLC)方法。样品经乙酸乙酯提取,正己烷液-液分配除脂,过HLB固相萃取小柱,用3mL10%甲醇淋洗,5mL100%甲醇洗脱,洗脱液用氮气吹干,残渣用1mL10%乙腈水溶液定容。采用超高效液相色谱分离,二极管阵列检测器检测,外标法定量。甲砜霉素在0.05~2.0mg/L,氟甲砜霉素在0.025~1.0mg/L范围线性关系良好,相关系数分别为0.9996、0.9999;样品加标平均回收率分别为80.0%、95.8%;相对标准偏差分别为5.6%、11.2%,甲砜霉素、氟甲砜霉素检出限分别为10μg/kg、5μg/kg。     

氯霉素类药物的高效液相色谱手性分离研究

利用Pirkle型(S,S)-Whelk-01手性柱对合霉素、甲砜霉素、氟甲砜霉素进行了对映体分离研究。考察了在正己烷流动相中醇类添加剂种类及浓度对其手性分离的影响,并采用液相色谱／质谱联用法对甲砜霉素的两个异构体峰进行了确证。结果表明：当异丙醇和叔丁醇为醇类添加剂时,合霉素和甲砜霉素获得较大分离因子,而使得氟甲砜霉素获得较大分离因子的是乙醇。合霉素在流动相为正己烷／乙醇=97：3时获得最大分离度是1．89;在正己烷／乙醇=90：10时,甲砜霉素、氟甲砜霉素都获得了很好的分离,最佳分离度R8分别达到1．84和3．94。     

共振瑞利散射光谱法测定甲砜霉素——基于与溴甲酚绿的反应

在pH 7.56的Tris-盐酸缓冲溶液中,一定量的甲砜霉素与1.0×10^-3mol·L^-1溴甲酚绿溶液1.5 mL在总体积10 mL中反应生成离子缔合物,产生共振瑞利散射光谱,在其最大共振光散射峰波长340 nm处测定共振瑞利散射的强度I_RRS。甲砜霉素的质量浓度在0.02～0.36 mg·L^-1范围内与扣除空白值的相应共振瑞利散射强度△I_RRS呈线性关系,方法的检出限（3s/k）为0.065 mg·L^-1。方法用于测定两种甲砜霉素药物中甲砜霉素的含量,并以此试样为基体,用标准加入法做回收率和精密度试验,测得其平均回收率在98.9%～102%之间,相对标准偏差（n=6）在1.4%～1.7%之间。     

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.     

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.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.