共查询到18条相似文献,搜索用时 46 毫秒
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报道了以双溴代烷烃和刺乌头碱合成刺乌头碱氢溴酸盐的方法. 用元素分析、红外光谱、高分辨质谱和核磁共振进行了表征. 并用X射线单晶衍射确定了标题化合物的绝对构型. 晶体结构表明, 该化合物通过分子间氢键形成了网状类似超分子结构. 晶体属于单斜晶系, P21空间群, 晶胞参数: a=1.0619(2) nm, b=1.2196(3) nm, c=1.2282(2) nm, β=90.87(1)°, V=1.59037(54) nm3, Z=2, Dm=1.428 g/cm-3, F(000)=720.0, µ=1.349 mm-1. 环 A, B, C, D, E和F分别呈船式、椅式、信封式、船式、船式和信封式. 其绝对构型被确定为1S,4S,5S,7S,8S,9S,10S,11S,13R,14S,16S,17R. 相似文献
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金属醇盐的合成及应用 总被引:6,自引:0,他引:6
金属醇盐,又称金属酸酯或金属烷氧基化合物,是被人誉为填补了有机化学和无机化学之间空白的广义金属有机化合物的一部分。它们的分子结构中至少有一个M—O—C(M 相似文献
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示波极谱滴定法测定生物碱氢溴酸盐类药物 总被引:6,自引:0,他引:6
以AgNO3作滴定剂,KNO3和磺基水杨酸为极谱底液,采用交流示波极谱滴定法测定氢溴酸山莨菪碱、氢溴酸东莨菪碱、氢溴酸加兰他敏三种生物碱氢溴酸盐类药物的含量。该法到目前为止未见报道,具有快速、准确、终点直观的特点。 相似文献
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A simple and efficient one-pot procedure has been developed for the synthesis of ω-bromoesters from aromatic aldehydes and diols in the presence of pyridinium hydrobromide perbromide (PHPB) and triethoxymethane in which aldehyde reacts first with diol and the product, cyclic acetal, reacts with PHPB to give the final product, ω-bromoesters. 相似文献
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Seema Varshney Pradeep K. Sharma Kalyan K. Banerji 《Journal of Chemical Sciences》1992,104(5):603-610
Oxidation of three lower oxyacids of phosphorus, viz. phosphinic, phenylphosphinic and phosphorous acids by pyridinium hydrobromide
perbromide (PHPB), is first-order with respect to both oxyacid and PHPB. There is no effect on addition of acylonitrile and pyridinium bromide.
On oxidation, deuterated phosphinic and phosphorous acids exhibit substantial kinetic isotope effects. The effect of solvent
composition on reaction rate indicates that the transition state is more polar than the reactants. Reaction rates were determined
at different temperatures and the activation parameters calculated. Alternative mechanisms, involving the two tautomeric forms
of the oxyacid, have been formulated and it has been concluded that the reaction proceeds through the pentacoordinated tautomer.
Transfer of a hydride ion from the oxyacid to PHPB, in the rate-determining step, has been proposed. 相似文献
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A CE electrochemiluminescence (CE-ECL) method for simultaneous determination of lappaconitine hydrobromide (LH) and isopropiram fumarate (IF) has been first established, with a chemically modified platinum electrode by europium (III)-doped Prussian blue analogue film as a working electrode. The conditions for CE separation and ECL detection are discussed and optimized in detail. It has been proved that 20 mmol/L phosphate buffer (pH 8.5) containing 5% (v/v) ACN and 0.17 mol/L SDS could achieve the most favorable resolution, and the high sensitivity of detection was obtained by maintaining the detection potential at 1.23 V. Under optimized conditions, a baseline separation for the two analytes was achieved within 6 min, and the standard curves were linear in the range of 1.0×10(-7) ~ 5.0 × 10(-5) g/mL for LH and 4.0 × 10(-8) ~ 1.0 × 10(-5) g/mL for IF with the detection limits (3σ) of 6.6 × 10(-8) g/mL for LH and 3.7 × 10(-8) g/mL for IF, respectively. The precisions of intra- and interday measurements for LH and IF were less than 4.21 and 2.61%, respectively. The applicability of the proposed method was illustrated in the determination of LH and IF in rabbit plasma with recoveries between 95.6 and 103.0%. 相似文献
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Selective transformation of thioamides to their corresponding carbonyl compounds are performed in high to excellent yields
under mild conditions using pyridinium hydrobromide perbromide (PHBP) as a mild and efficient reagent.
Correspondence: Moslem M. Lakouraj, Department of Organic Chemistry, Faculty of Chemistry, Mazandaran University, Babolsar
47416, Iran. 相似文献
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Summary A rapid and accurate HPLC method is described for the simultaneous determination of acetaminophen, dextromethorphen hydrobromide
and pseudoephedrine hydrochloride in a new cold formulation. Chromatographic separation of the three pharmaceuticals was performed
on a Hypersil CN column (150×5.0 mm, 5 μm) with a mobile phase mixture of an ion-pairing solution, methanol and acetonitrile
(25:57:18, v/v), at a flow rate of 1.0 mL min−1, with detection at 220 nm. Separation was complete in less than 10 min. The method was validated for linearity, accuracy,
precision, limit of quantitation and robustness. Linearity, accuracy, and precision were found to be acceptable over the ranges
of 2.06∼20.6 μg·mL−1 for acetaminophen, 0.202∼2.02 mg·mL−1 for pseudoephedrine hydrochloride and 0.042∼1.06 mg·mL−1 for dextromethorphen hydrobromide. 相似文献
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Md. Irshad Alam Aquil ur‐Rahim Siddiqui Nazia Khanam Shaikh Jalil Kamaruddin 《Journal of separation science》2020,43(18):3597-3606
An innovative high‐performance liquid chromatography assay method was developed and validated for quantification of dextromethorphan hydrobromide and desloratadine simultaneously in monophasic liquid formulation by preparing syrup containing 30 mg/5 mL of dextromethorphan hydrobromide and 1.2 mg/mL of desloratadine. The chromatographic severance was executed by gradient solution A and B. The composition of buffer solution A contained 0.05 M monobasic potassium, then 1 mL triethylamine was added to it and the pH was adjusted to 2.3 with orthophosphoric acid. Methanol was used as solution B. The gradient elution was executed with Kromasil C8 (250 mm × 4.6 mm) column having 1.5 mL/min flow rate and 20 µL injection volume with UV‐estimation at 254 nm for dextromethorphan hydrobromide and DES. The present research was planned according to Box‐Behnken design by utilizing design expert software, using four factors such as column temperature (A), flow rate (B), mobile phase–organic phase (C), and pH (D); correspondingly the selected response variables were resolution between A and B, that is, desloratadine and methyl paraben (Y1), tailing of dextromethorphan hydrobromide (Y2), and tailing of desloratadine (Y3). The parameters such as system suitability, linearity, accuracy, precision, robustness, limit of detection, limit of quantitation, and ruggedness were analyzed to validate the developed method in accordance with current regulatory guidelines. 相似文献
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The single-step synthesis of fused tricyclic pyridazino[1,2-a]indazolium ring systems is described. Structural details revealed by crystallography explain the unexpected reactivity. The method is applied to the gram scale synthesis of nigeglanine hydrobromide. 相似文献