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1.
12-Hydroxy-13-methylpodocarpa-9, 11, 13-trien-3-one 9 was isolated from the twigs ofCroton salutaris1. Many diterpenes exhibit significant bioactivities, such as antibac-terial and antitumour and 9 has a rare structure. In order to study the relationshipb…  相似文献   

2.
The first total synthesis of 3-oxo-11, 12, 13-trihydroxyeudesm-4-ene, a highly oxygenated natural eudesmane, was described.  相似文献   

3.
以双(2-羟基-3,5-二氯苯基)甲烷(4)与PSCl3关环,高收率地得到2,4,6,8,10-五氯-6-硫-12H-双苯并[d,g][1,3,2]二氧磷杂八环(5)。5与酚在无水K2CO3及铜粉存在下,或与醇在醇钠存在下反应,生成2,4,8,10-四氯-6-硫-6-芳氧基-12H-双苯并[1,3,2]二氧磷杂八环(6),或6-烷氧基的类似物(7)。5与醇在三乙胺存在下反应的产物为2,4,8,10-四氯-6-硫-6-羟基-12H-双苯并[1,3,2]二氧磷杂八环三乙胺盐(8)。8在DMSO中回流则氧化为它的氧类似物9。  相似文献   

4.
二溴苯羟基荧光酮荧光光度法测定微量锆   总被引:2,自引:0,他引:2  
本文提出了一个锆-二溴苯羟基荧光酮(DBHPF)-乳化剂OP荧光光度法测定微量锆的新体系,在0.5~1.2mol/L的HCl介质中,锆与DBHPF生成组化比为1:4的红色荧光性络合物,荧光强度与锆(Ⅳ)的浓度在0~100μg/L呈线性关系,检出限为2.0μg/L。灵敏度高,高选择性好,用于瓷釉等样品中ZrO2的测定,获得满意的结果。  相似文献   

5.
根据Schlosser-Wittig反应,采用溴代ω-羟基壬烷基三苯基膦盐与2E-戊烯醛反应,产物经进一步酯化生成淡褐苹果蛾性信息素-(9E,11E)-十四碳二烯-1-乙烯酯,产物中(9E,11E)异构体含量可达98%。  相似文献   

6.
An efficient one-step synthesis of the diacetate of the tetracyclic triterpenoid onoceranediol (4) by radical cleavage of the readily available 12-hydroperoxy-8α,12-epoxy-11-bishomodrimane is described. Drim-9(11)-en-8α-yl acetate (7) is formed in this reaction as a byproduct. Onoceranediol diacetate 4 is converted into onoceranediol on treatment with LiAlH4, and acetate 7 is transformed into drim-9(11)-en-8α-ol on saponification. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2571–2573, November, 2005.  相似文献   

7.
11-Aminodrim-7-ene was synthesized from drimenol in four steps. Drimenol was oxidized into drimenal and its oxime was dehydrated by p-tosylchloride or acetic anhydride in pyridine to form 9-cyano-11-nordrim-7-ene, reduction of which by LiAlH4 in the presence of anhydrous AlCl3 produced 11-aminodrim-7-ene. The reaction of 9-cyano-11-nordrim-7-ene, NaBH4, and CoCl2·6H2O produced a mixture of drimenylamine and 7,8-dihydrodrimenylamine in a 2:1 ratio. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 311–314, May–June, 2009.  相似文献   

8.
Reported are the syntheses, crystal structure determinations from single-crystal X-ray diffraction, and magnetic properties of two new ternary compounds, Eu11Cd6Sb12 and Eu11Zn6Sb12. Both crystallize with the complex Sr11Cd6Sb12 structure type—monoclinic, space group C2/m (no. 12), Z=2, with unit cell parameters a=31.979(4) Å, b=4.5981(5) Å, c=12.3499(14) Å, β=109.675(1)° for Eu11Zn6Sb12, and a=32.507(2) Å, b=4.7294(3) Å, c=12.4158(8) Å, β=109.972(1)° for Eu11Cd6Sb12. Their crystal structures are best described as made up of polyanionic and ribbons of corner-shared ZnSb4 and CdSb4 tetrahedra and Eu2+ cations. A notable characteristic of these structures is the presence of Sb-Sb interactions, which exist between two tetrahedra from adjacent layers, giving rise to unique channels. Detailed structure analyses shows that similar bonding arrangements are seen in much simpler structure types, such as Ca3AlAs3 and Ca5Ga2As6 and the structure can be rationalized as their intergrowth. Temperature-dependent magnetization measurements indicate that Eu11Cd6Sb12 orders anti-ferromagnetically below 7.5 K, while Eu11Zn6Sb12 does not order down to 5 K. Resistivity measurements confirm that Eu11Cd6Sb12 is poorly metallic, as expected for a Zintl phase.  相似文献   

9.
本文报道了以二溴羟基苯基荧光酮(DBH-PF)为指示剂,在阳离子表面活性剂CPC存在下荧光猝灭间接测定Br ̄-的新方法。在0.6mol/LH_2SO_4介质中,Br ̄-和BrO反应生成Br_2,Br_2与DBH-PF(λ_(ex)=495nm,λ_(em)=520nm)生成红色化合物,使体系荧光猝灭。Br ̄-含量在0.25~6.25μg/25mL范围内有良好的线性关系,检测限为0.25μg/25mL。该法灵敏度高,选择性好,用于合成海水样品中Br ̄-的测定,结果满意。  相似文献   

10.
采用圆二色谱和核磁共振波谱研究了Slc11a2第六跨膜区在十二烷基磷酰胆碱(DPC)膜模拟环境中的结构和定位.结果表明,Slc11a2第六跨膜区在DPC胶束中N端和C端各形成一小段α螺旋,两段螺旋中间通过高度灵活的区域连接,整个肽插入到DPC胶束中.H267A突变使螺旋长度变长,H272A突变使螺旋长度略有变短,突变后结构的变化可能和蛋白功能缺失相关.  相似文献   

11.
双分子维生素B_(12)模型分子的合成及表征   总被引:1,自引:0,他引:1  
维生素B_(12)经醇解得到的七甲基钴啉酯1作为起始原料,经酸性水解分别得 到b,c,d,e,f-单酸钴啉酯2b~2f, 2b~2f与3-咪唑基丙胺盐酸盐反应合成了相应的 酰胺钴啉酯衍生物3b~3f, 3b~3f在乙酸的作用下合成了双分子络合维生素B_(12) 模型化合物双-单腈六甲基-N-(3-咪唑基)丙酰胺钴啉酯高氯酸盐5b~5f,并对其 化学结构进行了表征。  相似文献   

12.
咔唑及其衍生物因其分子中有较大的共轭体系和较强的分子内电子转移特性,已在染料、农药及光学材料等领域得到较广泛的应用[1].  相似文献   

13.
The complexation reactions of cerium(III and IV) with 9-phenyl-2,3,7-trihydroxy-6-fluorone (H3 PF) have been studied in the presence and absence of some surfactants and protective colloids. Maximum enhancement of the chelate absorbances is obtained with the cationic surfactant cetylpyridinium bromide (CPB) or cetyltrimethylammonium bromide (CTAB). In thepH ranges 8.2–9.0 and 9.8–10.8 the ternary 1:3:3 and 1:4:3 cerium(III)-PF-CPB complexes are formed with molar absorptivities of 9.02 × 104 and 9.86 · 104 lmol–1 cm–1 at 570 and 590 nm, respectively. The corresponding 1:4:2 and 1:3:2 complexes of cerium(IV) are formed in thepH ranges 8.4–9.0 and 9.8–10.6 in the presence ofCTAB andCPB, respectively. Their molar absorptivities are 8.00·104 and 8.56·104lmol–1 cm–1 at 570 and 590 nm, respectively. The stability constants of the studied complexes have been determined and a spectrophotometric method has been developed to determine the cerium content in monazite concentrate.
Komplexierungsreaktionen von Cer(III und IV) mit 9-Phenyl-2,3,7-trihydroxy-6-fluoron in Gegenwart kationischer oberflächenaktiver Stoffe
Zusammenfassung Es wurden Komplexierungsreaktionen von Cer(III und IV) mit 9-Phenyl-2,3,7-trihydroxy-6-fluoron (H3 PF) in Gegenwart und auch ohne oberflächenaktive Stoffe und Schutzkolloide untersucht. Maximale Verstärkung der UV-VIS-Absorption wurde mit den kationischen oberflächenaktiven Verbindungen Cetylpyridiniumbromid (CPB) und Cetyltrimethylammoniumbromid (CTAB) erreicht. ImpH-Bereich von 8.2–9.0 und 9.8–10.8 bildeten sich die ternären 1:3:3 und 1:4:3 Cer(III)-PF-CPB-Komplexe mit molaren Extinktionskoeffizienten von 9.02·104, bzw. 9.86·104lmol–1 cm–1 bei 570 bzw. 590 nm. Die entsprechenden 1:4:2 und 1:3:2 Cer(IV)-Komplexe wurden impH-Bereich 8.4–9.0 und 9.8–10.6 in Gegenwart vonCTAB undCPB gebildet, wobei die Extinktionskoeffizienten bei 8.00·104, bzw. 8.56·104 lmol–1 cm–1 bei 570 bzw. 590 nm lagen. Es wurden die Stabilitätskonstanten der Komplexe bestimmt und es wurde eine spektrophotometrische Methode zur Bestimmung von Cer in Monazitkonzentrat entwickelt.
  相似文献   

14.
Oxidative coupling of derivatives of 4a,9-diaza-1,2,4a,9a-tetrahydro-9H-fluorene with 2-ethyl-, 2,2-dimethyl-, and 2-hydroxymethyl-2-methylaminoethanol in the presence of MnO2 led to the selective formation of the corresponding mono- and di(hydroxymethyl)quinonediimines, subsequent cyclization of which gave the products of 6,7-annelation. Coupling with 2,2-di(hydroxymethyl)aminoethanol gave the annelation products directly.  相似文献   

15.
6-Alkylcarbamato/alkylthiocarbamato-2,10-dichloro-12-trichloromethyl-12 H -dibenzo [d,g][1,3,2]-dioxaphosphocin 6-oxides have been synthesized by the condensation of 2,2-bis(2-hydroxy-5-chlorophenyl)-1,1,1-trichloroethane with dichlorophosphinyl carbamates of different alcohols/thiols in the presence of triethylamine in dry toluene and were characterized by different spectral studies.  相似文献   

16.
Here we report the direct chemical synthesis of coenzyme B12 (AdoCbl) from Coβ ‐5′‐deoxyadenosylcobyric acid (AdoCby) and the preparation of the latter from crystalline CN ,H2O‐cobyric acid (CN ,H2OC by). AdoCby is a suggested common key intermediate in the biosynthesis of AdoCbl and of other cobamides in microorganisms. AdoCby was thoroughly characterized by spectroscopic means, including homo‐nuclear and hetero‐nuclear NMR , as such data are not available in published work. AdoCbl was prepared from AdoCby in one‐step in over 85% yield, by covalent attachment in aqueous solution of the integral B12‐nucleotide moiety using 1‐ethyl‐3‐(3‐dimethylaminopropyl)‐carbodiimide (EDC ·HC l) and N‐hydroxybenzotriazole (HOB t) as coupling reagents. By the same procedure crystalline vitamin B12 (CNC bl) was also prepared in 92% yield from CN ,H2OC by. Coordination of the B12‐nucleotide base at the Coα ‐face of AdoCby or of CN ,H2OC by was indicated to assist in the efficient covalent coupling at the activated f‐side chain function to furnish the complete corrinoids AdoCbl and CNC bl.  相似文献   

17.
3, 3, 6, 6-Tetramethyl-1, 8-dioxo-9-aryl-1, 2, 3, 4, 5, 6, 7, 8, 9, 10-decahydroacridines and their derivatives are polyfunctionalized 1, 4-dihydropyridine derivatives. In recent years, much attention has been focused directly on the synthesis of 1, 4-dih…  相似文献   

18.
A synthetic route to 11-hydroxydrim-8(9)-en-7-one and 11,12-hydroxydrim-8(9)-en-7-one, valuable key intermediates for the preparation of naturally occurring biologically active drimanic sesquiterpenoids, starting from easily available drim-8(9)-en-7-one was developed. 11-Hydroxydrim-8(9)-en-7-one was obtained by peracidic oxidation of the enol acetate of drim-8(9)-en-7-one. 11,12-Dihydroxydrim-8(9)-en-7-one was synthesized from drim-8(9)-en-7-one by two routes, namely, by a five-step procedurevia 11-hydroxydrim-8(9)-en-7-one and by bromination of drim-8(9)-en-7-one with NBS to give 11,12-dibromodrim-8(9)-en-7-one followed by its acetoxylation and deacetylation. Deceased Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 95–98, January, 2000.  相似文献   

19.
Drim-9(11)-en-8α-ol and drim-9(11)-en-8β-ol were synthesized in six steps from drimenol. Drimenol was oxidized by P2O5 and DMSO to drimenal, which isomerized with p-TsOH into isodrimenal. Isodrimenal was reduced by NaBH4 into isodrimenol, epoxidation of which by m-CPBA gave a mixture (3.4:1) of α- and β-epoxyisodrimenols. These reacted with tosyl chloride in Py to give a mixture of α- and β-epoxyisodrimenol tosylates. Treatment of the tosylate mixture with KI and then Ph3P produced a mixture of drim-9(11)-en-8α- and -8β-ols that was separated chromatographically. The overall yield was ∼26%.__________Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 152–155, March–April, 2005.  相似文献   

20.
A synthetic route to 11-hydroxydrim-8(9)-en-7-one and 11,12-hydroxydrim-8(9)-en-7-one, valuable key intermediates for the preparation of naturally occurring biologically active drimanic sesquiterpenoids, starting from easily available drim-8(9)-en-7-one was developed. 11-Hydroxydrim-8(9)-en-7-one was obtained by peracidic oxidation of the enol acetate of drim-8(9)-en-7-one. 11,12-Dihydroxydrim-8(9)-en-7-one was synthesized from drim-8(9)-en-7-one by two routes, namely, by a five-step procedurevia 11-hydroxydrim-8(9)-en-7-one and by bromination of drim-8(9)-en-7-one with NBS to give 11,12-dibromodrim-8(9)-en-7-one followed by its acetoxylation and deacetylation. Deceased Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 95–98, January, 2000.  相似文献   

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