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1.
迄今为止,所报道的糠酸莫美他松的合成方法以起始原料分为两种.方法一:Shapiro[1],Draper[2],和Kwok[3-4]均采用9,β11β-环氧-17,α21-二羟基-16α-甲基-1,4-孕甾二烯-3,20-二酮(简称21-羟)为起始原料,经多步反应进行合成,且收率高达95%.方法二:Shapiro[3]以16α-甲基-1,4,9(1  相似文献   

2.
糠酸莫美他松是一强效的外用皮质激素制剂,具有优良的抗炎活性.其中间体9,β11β-环氧-17α-羟基-16α-甲基-21-碘代-1,4-孕甾二烯-3,20-二酮(简称21-碘化物)的分解对下一步置换反应的收率影响很大.本文首次对其分解率通过HPLC进行了测定,并给出了21-碘化物的较佳储藏方式.  相似文献   

3.
从豆甾醇出发,先合成了胆甾-5-烯-24-酮-3β-乙酸酯(2);再用过甲酸将2的5,6位双键氧化为环氧化物,后者在碱性条件下立体专一地开环得胆甾-3β,5α,6β-三羟基-24-酮(3),用醋酐将化合物3的C3-βOH和C6-βOH乙酰化保护后用亚硫酰氯脱水得胆甾-4-烯-24-酮基-3β,6β-二乙酸酯(4),4在碱性条件下脱去乙酰基得胆甾-4-烯-3β,6β-二羟基-24-酮(5);化合物5通过Wittig反应将C-24羰基亚甲基化得到目标化合物24-亚甲基胆甾-4-烯-3β,6β-二醇1,总产率为26%.合成化合物1的光谱数据与分离得到的天然物完全一致.  相似文献   

4.
采用硅胶柱色谱及HPLC等分离方法对鹿心雪茶正己烷提取物进行分离纯化,得到7个化合物,依据波谱数据分析鉴定它们的结构分别为:3,6-二甲基-2,4-二羟基苯甲酸甲酯(1)、2,4-二羟基-3-醛基-6-甲基苯甲酸甲酯(2)、羊角衣酸(3)、3β-羟基-5α,8α-过氧桥麦角甾-6,22(E)-二烯(4)、3β-羟基-5α,8α-过氧桥麦角甾-6,9,22(E)-三烯(5)、3β-羟基-5α-豆甾烷-4-烯-3-酮(6)、8α,11-elemodiol(7)。其中化合物6和7为首次从该植物中分离的到。  相似文献   

5.
本实验采用多种色谱手段及重结晶方法对青天葵石油醚部位的化学成分进行分离纯化,并根据波谱分析和理化常数等方法对化合物进行结构鉴定.共得到了10个化合物,分别为:β-谷甾醇(1)、豆甾醇(2)、6,9,10-三羟基-7E-烯十八烷酸(3)、麦角甾-7,22-二烯-3β,5α,6β-三醇(4)、豆甾-22-烯-3β,6β,9β-三醇(5)、麦角甾-7,22-二烯-3β,5α,6α-三醇(6)、3β-羟基豆甾-5,22-二烯-7-酮(7)、3β-羟基豆甾-5-烯-7-酮(8)、橙黄胡椒酰胺乙酸酯(9)、橙黄胡椒酰胺苯甲酸酯(10).其中化合物3、5~8、10为首次从青天葵植物中分离得到.  相似文献   

6.
醋酸泼尼松龙为肾上腺皮质激素类药物,具有抗炎、抗过敏和抑制免疫等多种药理作用.其中间体17α-羟基-21-碘代-1,4,9-孕甾三烯-3,20-二酮(简称DDPD)极易分解,使其对后续反应的产率影响很大.本文采用高效液相法对此碘代物的分解率进行测定,并给出其较佳的贮存方式.  相似文献   

7.
从子囊菌亚门黄盾盘菌(Scutellinia ascoboloides)发酵液中首次分离得到8个化合物,其结构通过光谱学技术确定为:α-甜没药醇(1),pelandjauic acid(2),geranicardic acid(3),(4E,8E)-N-2'-羟基棕榈酰-9-甲基-4,8-sphin-gadienine(4),麦角甾-7,22-二烯-3-酮(5),麦角甾-4,6,8(14),22-四烯-3-酮(6),麦角甾-5,7,22-三烯-3β-醇(7),麦角甾-7,22-二烯-3β,5α,6β-三醇(8).  相似文献   

8.
目的:研究开口箭根茎中甾体成分,寻找新的抗肿瘤活性物质.方法:运用反相常压柱色谱和制备高效液相对其甾体成分进行分离,通过理化性质和波谱分析方法鉴定其结构.结果:从开口箭根茎的乙醇提取物中分离得到6个甾体皂苷及2个甾体皂苷元,其结构分别为1β,2β,3β,4β,5β-五羟基-螺甾-△25(27)-烯-5-O-β-D-吡喃葡萄糖苷(1),1β,3β-二羟基-5β-孕甾-△16(17)-烯-20-酮-3-O-β-D-吡喃葡萄糖苷(2),1β,2β,3β,4β,5β,6β,7α-七羟基-5β-呋甾-△25(27)-烯(3),1β,2β,3β,4β,5β,7α-六羟基-6-氧化-螺甾-△25(27)-烯(4),3-O-β-D-吡喃葡萄糖基-(25S)-1β,3β,5β,26-四羟基-5β-呋甾-△20(22)-烯-26-O-β-D-吡喃葡萄糖苷(5),3-O-β-D-吡喃葡萄糖基-(25S)-1β,3β,5β,22α,26-五羟基-5β-呋甾-26-O-β-D-吡喃葡萄糖苷(6),3-O-β-D-吡喃葡萄糖基-(25S)-1β,3β,26-三羟基-5β-呋甾-26-O-β-D-吡喃葡萄糖苷(7)和3-O-β-D-吡喃葡萄糖基-(25R)-1β,3α,26-三羟基-△5(6)-烯-5β-呋甾-26-O-β-D-吡喃葡萄糖苷(8).结论:化合物1和2为首次从该属植物中获得.  相似文献   

9.
从南中国海采集的小棒短指软珊瑚Sinularia microclavata Tix-Dur中首次分离得2个氧化甾醇. 通过各种近代波谱分析方法,鉴定出它们分别为孕甾-5-烯-3-醇-20-酮(pregnenolone)(1)和9,11-开环-24-亚甲基-5α-胆甾-7-烯-3β,6α,11-三羟基-9酮(2).1和2均有较强的细胞毒活性.  相似文献   

10.
目的:分离鉴定链霉菌属放线菌H41-55发酵菌丝体中化合物结构.方法:运用硅胶柱色谱、凝胶色谱、高效液相色谱等手段对链霉菌属放线菌H41-55发酵菌丝体进行化学成分分离,利用高分辨质谱、核磁等技术鉴定化合物结构.结果:从链霉菌属放线菌H41-55发酵菌丝体分离最终得到15个化合物,确定它们的结构分别是吲哚-3-甲醛(1)、5-羟基-3-(1-羟基-2-甲基丁基)-1-甲基-2 (5H)-呋喃(2)、环-(L-脯氨酰-L-亮氨酰)(3)、6-(3-甲基-2-丁烯基)-3-吲哚乙腈(4)、抗霉素A9 (5)、kitamycin A (6)、泛醌Q9 (7)、麦角甾-7,22-二烯-3β,5α,6β-三醇(8)、麦角甾-8 (14),22E-二烯-3β,5α,6β,7α-四醇(9)、豆甾-7,22-二烯-3β,5α,6α-三醇(10)、5α,6α-环氧-(22E,24R)-麦角甾-8,22-二烯-3β,7α-二醇(11)、5a,6a-环氧-(22E,24R)-麦角甾-8,22-二烯-3β,7β-二醇(12)、3β,5α,9α-三羟基-(22E,24R)-麦角甾-7,22-二烯-6-酮(13)、4,6,8 (14),22-麦角甾四烯-3-酮(14)、(22E,24R)-麦角甾-4,7,22-三烯-3-酮(15).其中化合物8、10、14和15为首次从海洋来源链霉菌属中分离得到.结论:采用MTT法筛选15个化合物的体外抗肿瘤细胞毒活性,发现均具有一定的活性.其中,化合物2、5、6、7和14表现出较好的生长抑制活性,其IC50质量浓度均小于30μg/m L.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

13.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

14.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

15.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

16.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

17.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

18.
Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of  相似文献   

19.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

20.
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