The first direct synthesis of 4-O-cinnamoyl derivatives of quinic and shikimic acids were accomplished by regioselective esterification with Candida antarctica lipase A. For hydrocinnamic esters, enzymatic transesterification with vinyl esters gave excellent yields. However, more reactive acylating agents such as anhydrides were used to synthesize cinnamic derivatives of both acids. An inhibitory effect
Chemo-enzymatic synthesis of vinyl and l-ascorbyl phenolates and their inhibitory effects on advanced glycation end products
作者:Seung Hwan Hwang、Zhiqiang Wang、Soon Sung Lim
DOI:10.1016/j.foodchem.2016.07.118
日期:2017.1
bioassays to investigate their inhibitoryactivityagainstadvancedglycationendproducts (AGEs). Among them, vinyl 4-hydroxycinnamate (17VP), vinyl 4-hydroxy-3-methoxycinnamate (18VP), vinyl 4-hydroxy-3,5-dimethoxycinnamate (20VP), ascorbyl 4-hydroxy-3-methoxycinnamate (18AP) and ascorbyl 3,4-dimethoxycinnamate (19AP) showed 2–10 times stronger inhibitoryactivities than positive control (aminoguanidine
Palladium(II) Acetate as Catalyst in Transvinylation Reactions of Hydroxycinnamic Acid and Its Derivatives
作者:L.O. Kadidae、A. Usami、M. Honda
DOI:10.14233/ajchem.2018.21033
日期:——
The study on application of palladium(II) acetate as catalyst in transvinylation reactions of hydroxycinnamic acids has been done. This study was intended to assess the capability of palladium(II) acetate as a safer replacement for mercuric(II) catalysts in transvinylation reactions of hydroxycinnamic acids and its derivatives. Optimizing the performance of the catalyst by applying several additional catalysts in the reactions was firstly done. Among those catalysts, KOH and H2SO4 showed significant impacts on the yields of the transvinylation reactions. It increased to 96 % when KOH was added and to 95 % when H2SO4 was added, compared to only 66 % when palladium(II) acetate alone was employed. Adding either KOH or H2SO4 along with the primary catalyst of palladium(II) acetate in transvinylation reactions of hydroxycinnamic acids gave the desired products in good yields. This proved that palladium(II) acetate was capable of catalyzing the transvinylation reactions of hydroxycinnamic acid and its derivatives to produce some vinyl esters.