14326-08-0Relevant articles and documents
Methoxy group substitution on catechol ring of dopamine facilitates its polymerization and formation of surface coatings
Zhang, Jieyu,Cheah, Yong Shung,Santhanakrishnan, Sridhar,Neoh, Koon Gee,Chai, Christina L.L.
, p. 5 - 15 (2017)
Deposition of polydopamine on substrates is a facile and effective method of surface modification and the deposited polydopamine can reduce silver ions to form silver nanoparticles (AgNPs) for antibacterial applications. However, polydopamine deposition is a time-consuming process that usually requires 24?h to produce a dense surface coating. Since oxidation of dopamine is critical for its polymerization, we hypothesize herein that substitution of an electron-donating group on the catechol ring of dopamine can enhance its oxidation potential and subsequently accelerate its polymerization. In this work, dopamine substituted with a 5-methoxy group (OMeDA) was prepared. OMeDA polymerized faster than dopamine under similar reaction conditions, resulting in a polymer coating of 13?nm thickness on a silicon surface after 8?h, compared to the 24?h required for dopamine to form a coating of similar thickness. A polymer layer with AgNPs can be directly formed on the silicon substrate after exposure to a solution containing OMeDA and silver nitrate. After 2?h exposure, the silver content on the modified surfaces prepared with OMeDA was 187% higher than that obtained with dopamine, and the antibacterial efficacy of the former against Staphylococcus aureus was correspondingly higher than that of the latter. This study demonstrates that OMeDA with an electron-donating group in the catechol ring offers improvements over dopamine for surface modification applications.
Asymmetric total synthesis of (-)-plicatic acid via a highly enantioselective and diastereoselective nucleophilic epoxidation of acyclic trisubstitued olefins
Sun, Bing-Feng,Hong, Ran,Kang, Yan-Biao,Deng, Li
supporting information; experimental part, p. 10384 - 10385 (2009/12/23)
(Chemical Equation Presented) The first total synthesis of (-)-plicatic acid has been achieved by a concise and enantioselective route. In this synthesis, a conceptually new strategy featuring an asymmetric epoxidation-intramolecular epoxy-ring-opening Friedel-Crafts reaction sequence was developed for the stereoselective construction of the 2,7′- cyclolignane skeleton bearing contiguous quaternary-quaternary-tertiary stereocenters. The implementation of this strategy was enabled by the development of a modified protocol for the Seebach epoxidation with TADOOH, which affords an unprecedented, highly enantioselective and diastereoselective epoxidation with a range of α-carbonyl-β-substituted acrylates 3.
A novel strategy for the synthesis of benzofuran skeleton neolignans: Application to ailanthoidol, XH-14, and obovaten
Kao, Chai-Lin,Chern, Ji-Wang
, p. 6772 - 6787 (2007/10/03)
A convenient and general approach to the synthesis of the benzofuran skeleton compounds ailanthoidol, XH-14, and obovaten was developed. Starting from vanillin, a series of reactions afforded 7 in 71% yield. Treatment of 7 with n-BuLi followed by addition of substituted benzaldehydes resulted in the formation of carbinols 11 and 31. The substituted benzophenones obtained from oxidation of 11 and 31 were treated with trimethylsilyldiazomethane lithium salt to give diphenylacetylenes 15 and 33, respectively. 15 and 33 were then cyclized in the presence of either mercury acetate in acetic acid or bromine in chloroform to give 3-chloromercurio- or 3-bromobenzofuran, respectively. The 3-chloromercurio intermediates could be reduced to proton or derivatized to ester or bromide, leading to the synthesis of ailanthoidol, XH-14, and obovaten, respectively. In addition, necleophilic substitution was used to introduce a formyl or methyl group into the 3-bromobenzofuran derivatives, providing an alternative pathway to XH-14 and obovaten. The final elongation and deprotection reaction furnished the desired ailanthoidol, XH-14, and obovaten in yields of 30, 15, and 11%, respectively.
