Anti-oxidant activities of curcumin and related enones
作者:Waylon M. Weber、Lucy A. Hunsaker、Steve F. Abcouwer、Lorraine M. Deck、David L. Vander Jagt
DOI:10.1016/j.bmc.2005.03.035
日期:2005.6
anti-oxidant properties. There are conflicting reports concerning the structural/electronic basis of the anti-oxidant activity of curcumin. Curcumin is a symmetrical diphenolic dienone. A series of enone analogues of curcumin were synthesized that included: (1) curcumin analogues that retained the 7-carbon spacer between the aryl rings; (2) curcumin analogues with a 5-carbon spacer; and (3) curcumin
Supramolecular polymeric aggregation behavior and its impact on catalytic properties of imidazolium based hydrophilic ionic liquids
作者:Shoaib Muhammad、Muhammad Naveed Javed、Firdous Imran Ali、Ahmed Bari、Imran Ali Hashmi
DOI:10.1016/j.molliq.2019.112372
日期:2020.2
(ILs) self-assemble to form supramolecularpolymeric clusters/aggregates. The aggregation behavior of ILs influences its activity in the organic synthesis. However, the precise role of ILs in organic reactions is still unknown. It is, therefore, important to comprehend the supramolecularpolymeric aggregation behavior of ILs. We are exploring the supramolecularpolymeric aggregation behavior of ILs
离子液体(ILs)自组装形成超分子聚合物簇/聚集体。IL的聚集行为影响其在有机合成中的活性。但是,IL在有机反应中的确切作用仍是未知的。因此,重要的是要理解IL的超分子聚合聚集行为。我们正在使用电喷雾电离质谱(ESI-MS)探索IL的超分子聚合聚集行为。我们已经合成了四个亲水性IL(1-4),并研究了它们的聚集行为及其对碳-碳键形成(Knoevenagel和Claisen-Schmidt缩合)催化活性的影响。在这里,我们表明IL的聚集行为取决于阳离子和阴离子的类型和性质。ESI-MS(-ve)光谱揭示了两种不同类型的聚集,即[C n A n + 1 ] -和[A 2 + H + ] -。我们发现,催化活性随[C n A n + 1 ] -超分子聚集的增加而增加。因此,在IL中获得的最高收率的产品显示出阴离子-阴离子聚集的减少[A 2 + H +] – ESI-MS中的丰度。我们预计我们
Bio-Catalytic Bis-Michael Reaction for Generating Cyclohexanones with a Quaternary Carbon Center Using Glucoamylase
作者:Yong Zhang、Rui Li、Yan-Hong He、Zhi Guan
DOI:10.1007/s10562-016-1964-6
日期:2017.3
the construction of quaternarycarboncenters is reported. Glucoamylase from Aspergillus niger (AnGA) was used as a sustainable and eco-friendly catalyst. Various highly substituted trans-cyclohexanones with a quaternarycarboncenter were obtained with yields of up to 92%. As a novel case of enzyme promiscuity, this work provides a bio-catalytic alternative for construction of quaternarycarbon centers
Sugar-Based Organocatalyst for the Diastereoselective Desymmetrization of Dibenzylideneacetones
作者:Danielle L. J. Pinheiro、Gabriel M. F. Batista、Jaqueline R. Gonçalves、Talita N. Duarte、Giovanni W. Amarante
DOI:10.1002/ejoc.201501393
日期:2016.1
A Bronsted acid catalyzed highly regio- and diastereoselectivedesymmetrization of dibenzylideneacetones in the presence of azlactones is described (only 1,4 addition, > 20:1 dr). A novel organocatalyst based on D-galactose was synthesized and applied in this reaction. In terms of product, a new C–C σ-bond and two stereogenic centers are created, one of which is quaternary. The relative stereochemistry
Anti-melanogenesis screening of 47 synthesized curcumin-like diarylpentanoid analogues was performed to show that some had a potent inhibitory effect on the melanogenesis in B16 melanoma cells. Their actions were considered to be mostly due to tyrosinase inhibition, tyrosinase expression inhibition, and melanin pigment degradation. The structure–activity relationships of those curcumin-like diarylpentanoid analogues which inhibited the melanogenesis and tyrosinase activity were also discussed. Of those compounds assayed, (2E,6E)-2,6-bis(2,5-dimethoxybenzylidene)cyclohexanone showed the most potent anti-melanogenesis effect, the mechanism of which is considered to be the degradation of the melanin pigment in B16 melanoma cells, affecting neither the tyrosinase activity nor tyrosinase expression.