首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 171 毫秒
1.
在NaOH碱性介质中,1 (3 硝基苯基) 3 [4 (苯基偶氮)苯基] 三氮烯(m NPPAPT)分别与阳离子表面活性剂(CS)溴化十六烷基三甲铵(CTMAB)、溴化十二烷基二甲基苄铵(DDMBAB)、溴化十六烷基吡啶(CPB)和溴化十四烷基吡啶(TPB)反应显色形成离子配合物,它们与m NPPAPT形成离子配合物比均为2∶1。CTMAB、CPB、TPB、DDMBAB与m NPPAPT形成配合物最大吸收波长分别位于538、538、625、637nm,表观摩尔吸光系数达(103~104)L·mol-1·cm-1。研究了测定微量阳离子表面活性剂的条件,建立了新的分析方法,并应用于实样分析。  相似文献   

2.
Propyl O-(α-L-rhamncpyranosyl)-(1→3)-[2,4-di-O-(2s-methylbutyryl)-α-L-rham-nopyranosyl]-(1→2)-(3-O-acetyl-β-D-glucopyranosyl)-(1→2)-β-D-fucopyranoside (1), the tetrasac-charide moiety of Tricolorin A, was synthesized in total 23 steps with a longest linear sequence of 10 steps, and overall yield of 3.7% from D-Glucose. The isomerization of the dioxolane-type berzyli-dene in the presence of NIS/AgOTf was observed. Tetrasaccharide 1 exhibited no activity against the cultured P388 cell as Tricolorin A did.  相似文献   

3.
以苯甲醚为起始原料,与乙酰氯发生付-克酰基化后脱甲基得到4-羟基苯乙酮,然后与液溴进行α-溴代得到2-溴-1-(4-羟苯基)乙酮,再与叔丁胺进行胺化得到1-(4-羟基苯基)-2-(叔丁基氨基)乙酮,最后用氢硼化钠还原合成目标产物1-(4-羟基苯基)-2-(叔丁基氨基)乙醇,总收率约为42.3%。  相似文献   

4.
本文通过2-溴-N-(2-硝基苯)乙酰胺和取代的喹唑啉酮在NaH催化下发生亲核取代反应,再经过氢化、酸化合成了4个新型常山碱类抗球虫药物-N-(2-氨基苯基)-2-喹唑啉酮乙酰胺盐酸盐(1∶1)。其中,2-溴-N-(2-硝基苯)乙酰胺通过溴乙酰氯与邻硝基苯胺反应制备,取代的喹唑啉酮使用取代的邻氨基苯甲酸与甲酰胺反应合成。所有目标化合物的结构均经1H NMR,IR和HRMS等方法确证。  相似文献   

5.
研究了在阳离子表面活性剂溴化十六烷基三甲铵(CTMAB)存在下,2,3,7 三羟基 9 (4,5 二溴 邻硝基)苯基荧光酮(DBONPF)与钨(Ⅵ)的显色反应及光度性能。在0.4mol LH2SO4介质中,试剂与钨(Ⅵ)形成化学计量比为2∶1的红色络合物,其最大吸收峰位于547nm波长处,表观摩尔吸光系数为5.64×105L·mol-1·cm-1,检出限为4.12μg L,钨质量浓度在0~500μg L范围内符合比尔定律,分析方法可用于钢样中微量钨的测定。  相似文献   

6.
冯泳兰  邝代治 《分析化学》1999,27(7):836-840
合成了新试剂1-(2-羟基-3,5-二硝基苯基)-3-[4(苯基偶氮)苯基]-三氮烯(HDNPAPT),研究了该试剂在NaOH介质中与阳离子表面活性剂漠化十六烷基三甲铵(CTMAB)、溴化十六烷基吡啶(CPB)、溴化十二烷基二苄铰(DDMBAB)形成1:3的紫红色离子缔合物显色体系.测定了显色体系表面活性剂的临界胶束浓度、表观摩尔吸光系数ε_(max)、符合比尔定律的范围.探讨了微量阳离子表面活性剂CMTAB、CPB和DDMBAB的测定方法,结果满意.  相似文献   

7.
自菊科蒿属植物万年蒿(Artemisia Sacrorum Ledeb)地上部分首次分得三个贝壳杉烷型(Kauranetape)二萜类化合物,经理化常数测定及光谱分析(IR,’H-NMR,~(13)C-NMR,MS,二维核磁共振光谱)鉴定其结构分别为:3α,16α,17-三羟基贝壳杉烷[I],3α,16α-二羟基贝壳杉烷-17-0-β-D-葡萄糖甙[Ⅱ]和16α-羟基贝壳杉-3-酮-17-0-β-D-葡萄糖甙[Ⅲ]。其中[Ⅰ]为一新天然产物,[Ⅱ]为一未见报道的新化合物。通过对该三个化合物的~(13)C-NMR光谱分析,讨论了不同位置取代基对其~(13)C-NMR光谱化学位移的影响。  相似文献   

8.
由邻苯二甲酸酐为原料,经中间体3-羟基苯酞(3),再经溴丙烯及锡存在下3的烯丙基化、硼氢化氧化、铬酐氧化、二甲基锌甲基化,共6步反应合成了3-(3'-羟基丁基)异苯并呋喃-1(3H)-酮.  相似文献   

9.
黄永鹏  唐慧  宋云扬  陈博  钟辉 《色谱》2021,39(7):695-701
维库溴铵、罗库溴铵和泮库溴铵是一类广泛使用的非去极化肌松剂,使用过程中引起过敏反应甚至死亡的情况时有发生,快速检测血液中该类肌松剂的浓度,可为临床早期诊断提供有价值的信息.该类肌松剂为强极性的季铵盐类化合物,在反相色谱柱上难以保留,主要采用离子对色谱法进行分离.采用离子对色谱法时,加入的离子对试剂有离子抑制作用,可降低...  相似文献   

10.
以2-溴-4,5-二甲氧基苄溴为起始原料,依次经取代、Sonogoshira偶联、水解、酰化和氧化反应合成了新型FSH拮抗剂——(R)-N-[1-羟基-3-(1H-吲哚-3-基)丙烷-2-基]-3-异丙氧基-8,9-二甲氧基-6H-苯并[c]苯并吡喃-2-甲酰胺,总收率16.8%,其结构经~1H NMR和MS(ESI)确证。  相似文献   

11.
B. Pelc 《Tetrahedron》1978,34(20):3079-3080
1α,2β-Dihydroxycholesterol has been prepared from 1α,2β-epoxy-5α-cholestan-3β,6β-diol-3-acetate on reaction with methansulphonyl chloride and hydrochloric acid. The structure was confirmed by independent synthesis from 1α,2β-epoxycholest-5-en-3β-yl acetate.  相似文献   

12.
设计合成了两种新型的以聚吡唑硼酸盐、氨基酸为配体的钒氧配合物VO[phCH2CH(NH2)COO][HB(pz)3](1)和VO(3,5-Me2pz)[HB(3,5-Me2pz)3](CH3COO)(2). 通过元素分析、红外光谱对配合物进行了表征, 并利用单晶X射线衍射技术解析了它们的结构. 非等温热分解动力学研究表明, 配合物1和2的热分解反应都是分两步进行的. 通过计算, 配合物1热分解的第一步反应的可能机理为成核与生长(n=1/4); 第二步反应的可能机理为化学反应. 其非等温动力学方程分别为, dα/dT=(A/β)e-E/RT(1/4)(1-α)[-ln(1-α)]-3 和dα/dT=(A/β)e-E/RT(1-α)2. 分解反应的表观活化能分别是223.52 和331.94 kJ·mol-1; 指前因子ln(A/s-1)分别是49.67 和57.50. 配合物2 热分解的第一步反应的可能机理为化学反应; 第二步反应的可能机理为成核与生长(n=1/2). 其非等温动力学方程分别为, dα/dT=(A/β)e-E/RT(1-α)2, 和dα/dT=(A/β)e-E/RT(1/2)(1-α)[-ln(1-α)]-1. 分解反应的表观活化能分别是300.56 和444.72 kJ·mol-1; 指前因子ln(A/s-1)分别是75.53 和92.50.  相似文献   

13.
麦芽糖基(α-1→6)β-环糊精的酶法合成和结构鉴定   总被引:1,自引:0,他引:1  
采用地衣芽孢杆菌普鲁蓝酶合成Mal-β-CD, 反应产物体系成分简单, 易于分离, Mal-β-CD的转化率可达到56%.  相似文献   

14.
The deoxyfluorination reaction of β-diketones with N,N-diethyl-α,α-difluoro-m-methylbenzylamine (DFMBA) gave β-fluoro-α,β-unsaturated ketones in good yields. The reaction proceeded regioselectively, and only one regioisomer was obtained from the unsymmetrical 1-aryl-1,3-diketones. The reaction is applicable to diketones with a trifluoromethyl group, obtaining good yields of 3,4,4,4-tetrafluorobutenones. We used the resulting β-fluoro-α,β-unsaturated ketones for the reaction with lithium dialkyl cuprates.  相似文献   

15.
The first study of photooxidation reaction of 6β-acetoxyvouacapane isolated from Caesalpinia platyloba is reported. The reaction yielded four new epoxy lactones, 6β-acetoxy-15,16α-epoxy-13-spirocassa-12,16-olide, 6β-acetoxy-15,16β-epoxy-13-spirocassa-12,16-olide, 6β-acetoxy-12,13β-epoxycassa-16,12-olide and 6β-acetoxy-12,13α-epoxycassa-16,12-olide. All the structures were supported by 1D and 2D NMR spectroscopy as well as mass spectrometry. The stereochemistry was established on the base of single crystal X-ray diffraction.  相似文献   

16.
Reformatsky reaction of ethyl bromodifluoroacetate with N,N-(dibenzyl)-1H-benzotriazolyl-1-methylamine gave fully protected α,α-difluoro-β-alanine. Hydrogenolysis and hydrolysis furnished α,α-difluoro-β-alanine. Further transformation into N-phthalimido-α,α-difluoro-β-alanine was described.  相似文献   

17.
The 1,3-dipolar cycloaddition reaction of 1-vinylimidazole and β-(1-imidazolyl)-α,β-unsaturated carboxylic esters with N.α-diphenylnitrone and acetonitrile oxide was carried out and compared with those of β-pyrrolidinyl- and β-phenyl-α,β-unsaturated carboxylic esters. The imidazolyl moiety bonded to olefinic double bond was suggested to have properties intermediate to pyrrolidinyl and phenyl groups.  相似文献   

18.
A simple two-step method for the selective preparation of anomerically pure 1α- and 1β-(indol-2-yl)deoxyribose derivatives was developed. The synthesis was based on the Sonogashira reaction of 1α- and 1β-ethynyldeoxyribose and 2-haloanilines followed by a Pd-complex catalyzed cyclization to the corresponding indolyldeoxyribosides.  相似文献   

19.
N-Aryl-α,α-dichloroalkylarylketimines are formed from N-aryl-alkylarylketimines with N-chloro succinimide in carbon tetrachloride. Reaction of N-1-(2,2-dichlor-1-arylpropylidene)anilines with sodium methoxide the latter compounds formally involves migration of the notrogen atom from the 1- to the 3-position. The reaction of higher substituted N-aryl-α,α-dichloroalkylarylketimines with sodium methoxide leads mainly to α-chloro-α,β-unsaturated ketones. In the case of long-chain α,α-dichloroketimines, a formal γ-functionalization was observed. The reaction mechanisms are discussed in detail.  相似文献   

20.
Aldosterone 1 is a mineralocorticoid, it has great influence on the blood pressure and its glucuronide is an important marker for the detection of several diseases. Here, we describe the chemical synthesis of different aldosterone-18- and 20-glucuronides. Reaction of trimethylsilyl 2,3,4-tri- acetyl-1-β-glucuronic acid methyl ester 5 b and aldosterone diacetate 11 in the presence of TMSOTf gave the 18-α-glucuronide 9 a . The 18-β-glucuronide 15 b and the 20-β-glucuronide 16 b could be obtained by reaction of methyl 2,3,4-tri-O-isobutyryl-1α-glucuronate trichloroacetimidate 14 and aldosterone 21-acetate 8 in the presence of TMSOTf or BF3⋅OEt2. Finally, reaction of aldosterone 21-acetate 8 and methyl 2,3,4-triacetyl-1α-glucuronate trichloroacetimidate 19 in the presence of TMSOTf gave the corresponding methyl 18-β-triacetylglucuronate 9 b , which was transformed into the desired aldosterone-18-β-glucuronide 3 by two enzyma- tic transformations.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号