Reaction of Chalcones with Cellular Thiols. The Effect of the 4-Substitution of Chalcones and Protonation State of the Thiols on the Addition Process. Diastereoselective Thiol Addition

Several biological effects of chalcones have been reported to be associated with their thiol reactivity. In vivo, the reactions can result in the formation of small-molecule or protein thiol adducts. Both types of reactions can play a role in the biological effects of this class of compounds. Progress of the reaction of 4-methyl- and 4-methoxychalcone with glutathione and N-acetylcysteine was studied by the HPLC-UV-VIS method. The reactions were conducted under three different pH conditions. HPLC-MS measurements confirmed the structure of the formed adducts. The chalcones reacted with both thiols under all incubation conditions. The initial rate and composition of the equilibrium mixtures depended on the ratio of the deprotonated form of the thiols. In the reaction of 4-methoxychalcone with N-acetylcysteine under strongly basic conditions, transformation of the kinetic adduct into the thermodynamically more stable one was observed. Addition of S-protonated N-acetylcysteine onto the polar double bonds of the chalcones showed different degrees of diastereoselectivity. Both chalcones showed a Michael-type addition reaction with the ionized and non-ionized forms of the investigated thiols. The initial reactivity of the chalcones and the equilibrium composition of the incubates showed a positive correlation with the degree of ionization of the thiols. Conversions showed systematic differences under each set of conditions. The observed differences can hint at the difference in reported biological actions of 4-methyl- and 4-methoxy-substituted chalcones.     

Microwave-Assisted Michael Addition of Diethyl Malonate with Ferrocenyl Substituted Chalcones Under Solvent-Free Conditions

The article describes an efficient, economical, and environmentally friendly approach for Michael addition of diethyl malonate to ferrocenyl substituted chalcones in the presence of microwave irradiation under solvent-free conditions, affording the corresponding Michael adducts in moderate to good yields of 53–94%.

无溶剂条件下新型功能离子液体催化活性亚甲基化合物与查尔酮的Michael加成研究

以基于DBU(1,8-diazabicyclo[5.4.0]undec-7-ene)的新型功能离子液体[DBU][Ac],[DBU][Lac],[DBU][Tfa],[DBU][n-Pr]和[DBU][n-Bu]为催化剂,研究了无溶剂条件下活性亚甲基化合物与查尔酮的Michael加成反应.反应时间短、收率高、后处理简单、离子液体重复使用6次而活性未发现明显下降.     

1,5-二氮杂二环[4.3.0]-壬-5-烯与全氟烷基炔酸甲酯的Michael加成反应

1,5-二氮杂二环[4．3．0]-壬-5-烯(DBN)与全氟烷基炔酸甲酯发生Michael加成反应,生成的中间体发生分子内缩合产生了三环化合物。其结构经元素分析,IR,MS和核磁共振氢谱、碳谱,二维核磁共振^13C-^1H cosy谱,二维核磁共振^1H-^1H cosy谱确认。对反应机理也进行了探讨。     

Cross-linked Polyamides Prepared through Direct Bulk Michael Addition and Polycondensation from 1,6-Hexanediamine and Methyl Acrylate

Cross-linked polyamides(c PAs)were prepared through direct bulk Michael addition and subsequent polycondensation.Several mixed hexanediamine multi-esters(HDAMEs)were generated through the Michael addition of 1,6-hexanediamine(HDA)and methyl acrylate(MA)at50℃ with different HDA/MA molar ratios.Melt polycondensation of HDAMEs then proceeded at 150 or 170℃ in flasks to obtain viscous fluids,and curing was continued in tetrafluoroethylene molds to obtain c PA films.The Michael addition was monitored on the basis of FTIR and ESI-MS spectra.The c PA films were characterized by DSC,TGA,dynamic mechanical analysis,and tensile test.These directly prepared c PAs exhibited Tg of 1–39℃,tensile strength of up to 45 MPa,and strain at break from 18%to 40%.The c PAs with high tensile strength and good toughness were successfully synthesized through the direct bulk Michael addition from HDA and MA followed with polycondensation.     

查尔酮参与的不对称Michael加成反应研究进展

综述了近十年来,金鸡纳碱、硫脲、手性离子液体、季铵盐、脯氨酸和葡萄糖类衍生物等有机小分子在催化查尔酮的不对称Michael加成反应中的应用.有机小分子催化的机理大部分都是通过氢键、离子键等与底物相互作用而使其有较好的对映选择性.     

亚甲基丙二酸亚异丙酯衍生物的氰化加成

对5-位不饱和双键的氰化加成进行了研究,合成了一系列新的5-氰基甲基丙二酸亚异丙酯的衍生物.     

A modified and convenient method for the preparation of N-phenylpyrazoline derivatives

Ten new N-phenylpyrazoline derivatives have been synthesized in high yields by condensation of chalcones with phenylhydrazine in the presence of potassium carbonate in reflux conditions. The workup is simple and involves treatment with ice-cold water. As compared with the previous method a considerable increase in the reaction rate with better yields has been observed. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1032–1036, July, 2006.     

无溶剂Michael加成反应的新进展

无溶剂参与的Michael加成反应,具有收率高,选择性强,操作简捷和成本低廉的优点,尤其有利于对环境的保护.在无溶剂条件下,各种高效的碱性、酸性催化剂,特别是手性催化剂的使用,不仅实现了有机合成化学方法学的新突破,也拓宽了该类反应的应用范围.简要综述了无溶剂Michael加成反应的新近研究进展,详细讨论了碱性、酸性等催化剂以及无任何催化剂参与的此类反应.     

Triphenylphosphine-Catalyzed Michael Addition of Alcohols to Acrylic Compounds

A facile triphenylphosphine-catalyzed Michael addition of alcohols to acrylic compounds was described. The reaction was carried out in open air at refluxing temperature in the presence of 10 mol% PPh3. Michael addition of saturated and unsaturated alcohols to acrylonitrile or acrylates has been examined. The reaction gave β-alkoxy derivatives with isolated yields of 5%-79%. PPh3 is cheaper and more stable than those trialkylphosphines previously used for the similar reactions, and the products can be easily separated from the reaction mixture via distillation.     

酶促尿嘧啶与丙烯酸乙酯Michael加成反应的研究

考察了4种水解酶在尿嘧啶与丙烯酸乙酯Michael加成反应中的催化效率.初步探讨了反应溶剂,反应温度,反应时间,底物配比,酶添加量等反应条件对该加成反应的影响.筛选得到最适反应条件,在该反应条件下,Michael加成反应产率可达61·2%.     

Iodine-Catalyzed Mild and Efficient Method for the Synthesis of Chalcones

Molecular iodine is found to catalyze the condensation of acetophenones with various aromatic aldehydes to prepare chalcones.     

Synthesis and Characterization of Cyclotriphosphazenes Bearing Chalcones Derivatives

A series of new cyclotriphosphazenes bearing chalcones derivatives, N₃P₃Cl₅[OC₆H₄ CH=CHC(O)C₆H₄OC_nH_2n+1] and N₃P₃[OC₆H₄CH=CHC(O)—C₆H₄OC_nH_2n+1]₆, has been synthesized. A convenient synthetic method was performed from the reaction of hexachlorocyclotriphosphazenes with one and six equivalents of (E)-3-(4-(alkyloxy)phenyl)-1-(4-hydroxyphenyl)prop-2-en-1-one (2a–c). The compounds differ in the length of alkyl groups, C_nH_2n+1, where n = 10, 12, and 14, respectively. All the products were obtained in high yields. The structures of the synthesized compounds were defined by elemental analysis, IR, ¹H, ¹³C, and ³¹P NMR.     

I2-catalyzed Michael addition of indole and pyrrole to nitroolefins

An easy and efficient method to generate indolyl nitroalkane 5 and pyrrolyl nitroalkane 7 in high yields using β-nitrostyrene and indole/pyrrole at room temperature in the presence of catalytic amount of iodine is reported. The short reaction times and high yields of product are noteworthy. Molecular iodine promoted Michael addition is operationally simple and efficient method compared to the known Lewis acids or rare earth metal catalysts to generate different indolyl/pyrrolyl nitroalkanes in high yield.     

Enantioselective Michael Addition of Water

The enantioselective Michael addition using water as both nucleophile and solvent has to date proved beyond the ability of synthetic chemists. Herein, the direct, enantioselective Michael addition of water in water to prepare important β‐hydroxy carbonyl compounds using whole cells of Rhodococcus strains is described. Good yields and excellent enantioselectivities were achieved with this method. Deuterium labeling studies demonstrate that a Michael hydratase catalyzes the water addition exclusively with anti‐stereochemistry.     

环己酮与查尔酮的无溶剂Michael加成反应

以环己酮和查尔酮为原料, 在 NaOH 存在下无溶剂室温研磨反应, 非常方便地得到Michael加成产物. 该方法具有反应条件温和、操作简单和产率较高等优点, 并通过IR, ¹H NMR和元素分析确证产物的结构.     

Diastereoselective Ruthenium-Catalyzed Michael Addition of Indoles to Hormone Steroids: An Efficient Route to New Indole Derivatives

Diastereoselective conjugate 1,4-addition of indoles to α,β-unsaturated carbonyl compounds (hormone steroids) using Ru(III) as catalyst is reported. It was found that RuCl₃·nH₂O catalyzes the Michael addition of indoles to hormone steroids, providing new 3-alkylated derivatives in good to excellent yields.     

Efficient Synthesis of Deoxybenzoins from Chalcones

β‐Ketoaldehydes derived from chalcone epoxides by Lewis acid–catalyzed rearrangement underwent smooth deformylation when refluxed in tetrahydrofuran (THF) in the presence of ethylenediamine, affording deoxybenzoins in excellent yields. The method is general and useful for the preparation of deoxybenzoins with a variety of substitution patterns.