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 173 毫秒
1.
《Tetrahedron: Asymmetry》2001,12(7):1015-1023
1,3-Dioxolanone alcohols, prepared via the addition of chiral lithium enolates of 1,3-dioxolan-4-ones to aldehydes, are suitable intermediates for the synthesis of chiral trisubstituted isoserines or trisubstituted 3-hydroxy-β-lactams. In particular, the methyl ester of 2-methyl-3-(2-furyl)isoserinic acid and two 3-methyl-3-hydroxy-β-lactams bearing either a 2-furyl or a phenyl substituent at C-(4) have been prepared. The (2R,3S) stereochemistry of the isoserine, and the (3R,4S) stereochemistry of the two β-lactams is that required for the synthesis of taxoid analogues having the side-chain with the proper (2′R,3′S) configuration.  相似文献   

2.
A method has been developed for the synthesis of 1′-R-1′,4′-dihydro-2,3′-biquinolin-4′-ones based on the interaction of quinaldine with N-alkyl-N-formylanthranilic acid methyl esters under the conditions of the Claisen condensation. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 409–410, March 2008.  相似文献   

3.

A new nitrogen-rich energetic salt of bis-1-methylimidazole 1H,1′H-5,5′-bistetrazole-1,1′-diolate salt, (1-M)2BTO, was synthesized and characterized (FT-IR, 1H NMR, 13C NMR, elemental analysis, and X-ray single-crystal diffraction). Results indicated that (1-M)2BTO crystallizes in the triclinic space group P-1. The thermal decomposition behavior of (1-M)2BTO was determined by differential scanning calorimetry (DSC) and thermogravimetric tandem infrared spectroscopy. The decomposition peak temperature of (1-M)2BTO was 530 K, which suggested that the salt is strong heat resistance. The apparent activation energies were 130.56 kJ mol?1 (Kissinger’s method) and 132.50 kJ mol?1 (Ozawa’s method), respectively. The enthalpy of formation for the salt was calculated as 917.3 kJ mol?1. The detonation velocity and detonation pressure of (1-M)2BTO were 7448 m s?1 and 20.7 GPa, respectively, using the Kamlet-Jacobs equation. Furthermore, the sensitivity test results showed that its impact sensitivity is greater than 50 J and friction sensitivity is 180 N, indicating that it has a lower sensitivity.

  相似文献   

4.
5.
The reaction of 1-(4-methoxyphenyl)-1-(1-methylcyclohexyl)ethanol with nitriles in concentrated sulfuric acid afforded 1′-substituted 6′-methoxy-4′,4′-dimethyl-4′H-spiro[cyclohexane-1,3′-isoquinolines] as a result of consecutive Wagner-Meerwein rearrangement and Ritter reaction.  相似文献   

6.
Abstract

Some authors have shown that tetrahydropyrimidine-2-thiones are hydrated in acidic solution and then isomerise to the 2-imino-or 2-enamino-1,3-thiazine.  相似文献   

7.
《Analytical letters》2012,45(18):2239-2258
Abstract

Fluorescence properties of 2,2′-dihydroxy-3,3′-dicarboxy -1,1′-dinaphthylmethane (pamoic acid) and of its aluminium 1:1 complex are described. The fluorescence of the latter, as measured from a water-dioxane (3:7, v/v) solution, at pH 5.05–5.20, at room temperature, is used as a basis for a new method of aluminium determination at submicrogram level. Limit of quantification of the proposed procedure is 0.028 ng.ml?1, range of applicability goes up to 1.7 ug.ml?1, RSD is 1% at 0.47 ug.ml?1 level (concentrations, given refer to HCl solution which is measured) Tolerance ratios for several interferent metal ions are given. A comparison is made with Kirkbright's method which uses 3-hydroxy-2-naphthoic acid as complexing agent: stability with time of the readings and freedom from Fe(III) interference are the main advantages of the proposed procedure. The new method is applied to the aluminium determination in atmospheric aerosol samples.  相似文献   

8.
1INTRODUCTIONTheCIDT(N-cyanoimido-S,S-dimethylthiocarbo-nate)hasbeenwidelyutilizedinorganicsynthesisduringthelasttwodecadesandhasbecomeveryusefulforconstructingfunctionalizedheterocyliccom-poundsbecauseoftheirversatility.MuchattentionhasrecentlybeenfocusedonthedevelopmentofCIDTaswellastheirsyntheticapplications[1~4].Meanwhile,manypyrazoleandtriazolederivativesarereportedtoshowvariousbiologicalactivities,suchasantifungal[5],herbicidal[6~8],insectcidal[9]andotheractivities[10~12].Thu…  相似文献   

9.
The methyl ester of N-allyl-2-methoxycarbonylsuccinanilic acid is partially converted to 1,1′-diallyl-4,4′-dihydroxy-1H,1′H-[3,3t′]biquinolinyl-2,2′-dione in refluxing toluene in the presence of metallic sodium. A possible mechanism for the occurrence of these chemical processes is discussed. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1033–1038, July, 2008.  相似文献   

10.
Specific features of the molecular and crystal structures of 1,5-bis-(4′,4′,4′-trifluoro-1′-methyl-3′-oxo-but-1′-enylamino)-3-oxapentane are determined by single crystal XRD.  相似文献   

11.
12.
13.
Steroidal ketone thiosemicarbazones (4–6), obtained from the corresponding ketones(1–3), on oxidative cyclization with H2O2 at 0°C provide title compounds (7–9), respectively. The structures of these compounds have been established on the basis of their elemental analytical and spectral data.  相似文献   

14.
The crystal structure of the title compound(C24H24N2O5, Mr = 420.45) has been determined by single-crystal X-ray diffraction. The crystal is of triclinic, space group P1 with a = 8.991(1), b = 11.166(1), c = 11.169(1) , α = 91.413(2), β = 105.887(2), γ = 90.992(2)°, V = 1077.8(2) 3, Z = 2, Dc = 1.296 g/cm3, F(000) = 444, μ(MoKα) = 0.091 mm-1, the final R = 0.0466 and wR = 0.1507 for 4185 observed reflections(I 2σ(I)). The single-crystal X-ray diffraction data indicated intermolecular C(17)–H(17)O(4), C(5)–H(5)… O(4) hydrogen bonds and C–H…π interaction in the structure.  相似文献   

15.
The 1,4-dihydro-2,3-biquinolyl reacts with organolithium compounds to form the mixture of 4-R-1,4-dihydro-2,3-biquinolyls and 2-R-1,2-dihydro-2,3-biquinolyls in the ratio analogous to the conversion in the series of 2,3-biquinolyl. The utilization of the complex, the organolithium compound-TMEDA, in this process leads, after treatment of the reaction mixture with water, exclusively to 2-R-1,2-dihydro-2,3-biquinolyls. Treatment with methyl iodide leads to 1-methyl-2-R-1,2-dihydro-2,3-biquinolyls.  相似文献   

16.
2′-Oxo-1′,2′-dihydrospiro[cyclopropane-1,3′-indole]-2,2,3,3-tetracarbonitriles reacted with oxygencentered nucleophiles to form addition products at the cyano groups with conservation of the three-membered ring. Reactions of the title compounds with alcohols required the presence of base catalyst, and the products, 2-amino-4,4-dialkoxy-2′-oxo-1′,2′-dihydrospiro[3-azabicyclo[3.1.0]hex-2-ene-6,3′-indole]-1,5-dicarbonitriles, were converted into the corresponding 2-imino-2′,4-dioxospiro[3-azabicyclo[3.1.0]hexane-6,3′-indole]-1,5-dicarbonitriles and 2,2′,4-trioxospiro[3-azabicyclo[3.1.0]hexane-6,3′-indole]-1,5-dicarbonitriles by the action of acetic and sulfuric acids, respectively. The reactions with ketone oximes occurred in the absence of a catalyst, yielding 2-amino-4,4-bis(alkylideneaminooxy)-2′-oxo-1′,2′-dihydrospiro[3-azabicyclo[3.1.0]hex-2-ene-6,3′-indole]-1,5-dicarbonitriles. The reactions with thiols, aliphatic amines, and anilines were accompanied by opening of the three-membered ring. In the reactions with triphenylphosphine and thiols 2-(2-oxo-2,3-dihydro-1H-indol-3-ylidene)malononitrile was obtained, while morpholine and N,N-dimethylaniline gave rise, respectively, to 3,3-diaryl-and 3,3-dimorpholino-1H-indol-2(3H)-ones and tri- and dicyanoethylene derivatives.  相似文献   

17.
A general method has been proposed for synthesizing 3-(3-acetyl-5-aroyl-1,3,4-oxadiazolyl-2)-chromones that has been based on conversion of 3-formylchromones to acylhydrazones and of theacylhydrazones into the heterocyclic chromones.  相似文献   

18.
曹玲华  张林  顾军 《有机化学》2002,22(6):405-410
报道了3-甲酰基色酮经Jones试剂氧化后得到3-羧基色酮,再与3-芳基-4 -氨基-5-硫酮-1,2,4-三唑在POCl3作用下,得到一系列3-(3′-芳基- 5′-硫酮-1′,2′,4′-三唑-′-基)-氨甲酰基色酮类化合物。所有化合 物的结构均经IR,LCMS,^1HNMR,元素分析确证。  相似文献   

19.
20.
1INTRODUCTIONPolarizedketenedithioacetalshavebeenex-tensivelyusedasbuildingblocksinorganicsyn-thesis,especiallyinthesynthesisofheterocycliccompounds[1~6].Pyrazoleanditsderivativesrepre-sentoneofthemostactiveclassesofcompoundspossessingwidespectraofbiologicalactivities.Overthepastfewyears,considerableevidenceshavebeenaccumulatedtodemonstratetheefficacyofpyrazolederivatives,suchasantibacterial[7],fun-gicidal[8],herbicidal[9],insecticidal[10]andotherbiologicalactivities[11,12].Uptonow,alarg…  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