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1.
2H-吡喃-2-酮及其衍生物是有机合成的蓬要中间体。对于它们的合成已有许多报道,例如利用烯醇醚或烯醇砖醚与丁酰氯反应;羰基化合物与甲氧亚甲螭丙二酸二甲酯反应;α-苯基丙醛酸酯与丙酮的成环缩合2,6-二氯-3-三氯甲基吡啶与亚甲基丁二酸酯的反应,邻氰基苯乙炔、二苯乙二酮和丙酮的反应。但上述方法往往原料较难得到,产率较低或操作麻烦。 相似文献
2.
Alessandro?De?Robertis Concetta?De?Stefano Demetrio?Milea Silvio?SammartanoEmail author 《Journal of solution chemistry》2005,34(10):1211-1226
Complex formation constants were determined potentiometrically (by a ISE-H+, glass electrode) in the systems, M2+ – Lz – H+ [M2+ = (C2H5)2Sn2+, Lz = malonate, glycinate and ethylenediamine] at t = 25 ∘C and 0.1 mol-L−1≤ I/ ≤ 1 mol-L−1 in NaClaq (0.1 mol-L−1 ≤ I ≤ 0.75 mol-L−1 for the ethylenediamine system). Thermodynamic values of formation constants, at infinite dilution, are [± 95% confidence
interval, Tβpqr refer to the equilibrium, pM2+ + qLz + rH+ = MpLqHr(2+z+r)]: for malonate, log10 Tβ110 = (5.47 ± 0.10); for glycinate, log10 Tβ110 = (9.54 ± 0.08), log10 Tβ111 = (12.97 ± 0.10); and for ethylenediamine, log10 Tβ110 = (10.47 ± 0.10), log10 Tβ120 = (16.17 ± 0.12) and log10 Tβ111 = (15.46 ± 0.10). The dependence on ionic strength of the formation constants was modeled by a simple Debye–Hückel type equation
and by the SIT approach. By analyzing the stability of the species in the three different systems we found a simple additivity
rule that can be expressed by the relationship: log10 K = 6.46 nN + 3.96 nO − 0.60 (nN2+ nO2), with a mean deviation, ε(log10 K) = 0.15 (K = equilibrium constant for the interaction of the organometal cation with the unprotonated or protonated ligand, nN = number of amino groups and nO = number of carboxylic groups of the ligand(s) involved in the formation reaction of complex species). 相似文献
3.
B. P. Nandeshwarappa D. B. Aruna Kumar M. N. Kumaraswamy Y. S. Ravi Kumar H. S. Bhojya Naik K. M. Mahadevan 《Phosphorus, sulfur, and silicon and the related elements》2013,188(7):1545-1556
A series of novel substituted thiopyrano[2,3-b]quinolines 4a–e , 5a–e , and 6a–e were prepared from substituted 3-formyl-2-mercapto quinolines 2a–e , on reaction with ethyl acetoacetate, diethyl malonate, and ethyl cyanoacetate 3a–c by microwave irradiation in the presence of piperidine. Synthesized compounds were evaluated for antimicrobial activities. Among the compounds tested, 7-chloro-2-oxo-2H-thiopyrano[2,3-b]quinoline-3-carbonitrile 6d and 7-nitro-2-oxo-2H-thiopyrano[2,3-b]quinoline-3-carbonitrile 6e were highly active against S. aureus and M. roseus. 相似文献
4.
Summary The reaction between alkyl isocyanides and isopropylidene Meldrum’s acid in the presence of 1,2-ethanediol leads to N
1-(alkyl)-2-(5,7-dioxo-1,4-dioxepane-6-yl)-2-methylpropanamides. 1,3-Propanediol or 1,4-butanediol produce hydroxyalkyl 1-(tert-butyl)-4,4-dimethyl-2,5-dioxo-3-pyrrolidinecarboxylates. When the reaction was performed in the presence of catechol, bis(2-hydroxyphenyl)
2-[2-(tert-butylamino)-1,1-dimethyl-2-oxoethyl]malonate was obtained. 2-Aminophenols react with alkyl isocyanides in the presence of
isopropylidene Meldrum’s acid to produce 1-alkyl-N
3-(2-hydroxyaryl)-4,4-dimethyl-2,5-dioxo-3-pyrrolidinecarboxamides in good yields. 相似文献
5.
以USY分子筛为载体,采用共沉淀-浸渍法制备分子筛超强酸SO42-/Ti O2/USY,用其催化丙二酸、无水乙醇合成胡萝卜酸乙酯。考察了不同反应时间、带水剂种类、带水剂用量、醇酸比、催化剂用量、催化剂重复使用性等因素对反应酯化率的影响。结果表明:在丙二酸用量为0.1mol,醇酸摩尔比为3.1:1,催化剂用量为1.0g,反应时间为3h,带水剂环已烷用量为5m L时,酯化率达到92.13%,催化剂重复使用5次以后仍然有很高的活性。说明SO42-/Ti O2/USY对该反应具有很强且极稳定的催化活性。 相似文献
6.
7.
Calcium malonate (Camt) is used to induce the β crystalline form in isotactic polypropylene (iPP) for the first time. The relative content of the β crystalline form (K value) increases markedly with the addition of Camt and attains the maximum value of 73.48% at 0.40% Camt. The amounts of bright and colorful β spherulites increase and the spherulitic sizes decrease with the increase in Camt contents. The tensile strength and the Izod notched impact strength of the nucleated iPP samples increase with the addition of Camt; in particular, the latter almost doubles at 0.40% Camt compared to that of the blank iPP sample. The β nucleation mechanism of Camt is analyzed by the dimensional lattice match criterion. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
8.
The highly efficient selective monohydrolysis of symmetric diesters has been applied to monohydrolysis of several dialkyl malonates and their derivatives. The best conditions apply 0.8-1.2 equiv of aqueous KOH with a co-solvent, THF or acetonitrile, at 0 °C. The procedure is highly practical, yielding the corresponding half-esters in high yields in a straightforward manner, without inducing decarboxylation. It was found that the selectivity tends to become higher with increased hydrophobicity. 相似文献
9.
A series of vinylogous thiol esters 2,3 and 2,6-dioxo-1,2,5,6-tetrahydropyridines (cyclic vinylogous thiol esters) 4 were prepared in high to excellent yields from the tandem reaction of readily available α-alkenoylketene diethylthioacetals 1 and diethyl malonate. A plausible mechanism, which involves a base catalyzed retro-Michael ring opening of cyclohexanenes 2 to give vinylogous thiol ester 3, is disclosed. 相似文献
10.
Varghese MathewK.C. Mathai C.K. MahadevenK.E. Abraham 《Physica B: Condensed Matter》2011,406(3):426-429
Single crystals of nickel malonate dihydrate were grown by the gel technique, employing the single diffusion method. Thermal dehydration of the crystal was investigated by thermogravimetric and differential thermal analyses. The title compound exhibits a steady thermal behaviour at higher temperature range of 350-800 °C. The dielectric properties of the prepared sample were analyzed as a function of frequency in the range of 1 kHz-1 MHz and at temperatures between 40 and 140 °C. 相似文献