- Rational Design of 2-Substituted DMAP- N-oxides as Acyl Transfer Catalysts: Dynamic Kinetic Resolution of Azlactones
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A novel concept that conversion of chiral 2-substituted DMAP into its DMAP-N-oxide could significantly enhance the catalytic activity and still be used as an acyl transfer catalyst is presented. A new type of chiral 2-substituted DMAP-N-oxides, derived from l-prolinamides, has been rationally designed, facilely synthesized, and applied in the dynamic kinetic resolution of azlactones. Using simple MeOH as the nucleophile, various l-amino acid derivatives were produced in high yields (up to 98% yield) and enantioselectivities (up to 96% ee). Furthermore, α-deuterium labeled l-phenylalanine derivative was also obtained. Experiments and DFT calculations revealed that in 2-substituted DMAP-N-oxide, the oxygen atom acted as the nucleophilic site and the N-H bond functioned as the H-bond donor. High enantioselectivity of the reaction was governed by steric factors, and the addition of benzoic acid reduced the activation energy by participating in the construction of a H-bond bridge. The theoretical chemical study indicated that only when attack directions of the chiral catalyst were fully considered could the correct calculation results be obtained. This work paves the way for the utilization of the C2 position of the pyridine ring and the development of chiral 2-substituted DMAP-N-oxides as efficient acyl transfer catalysts.
- Deng, Yun,Guo, Hai-Ming,Huang, Bin,Li, Ning,Qu, Gui-Rong,Tian, Yin,Wu, Xiao-Xia,Xie, Ming-Sheng
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supporting information
p. 19226 - 19238
(2020/11/13)
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- Selective HDAC inhibitors with potent oral activity against leukemia and colorectal cancer: Design, structure-activity relationship and anti-tumor activity study
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Previously, we reported the discovery of a series of N-hydroxycinnamamide-based HDAC inhibitors, among which compound 11y exhibited high HDAC1/3 selectivity. In this current study, structural derivatization of 11y led to a new series of benzamide based HDAC inhibitors. Most of the compounds exhibited high HDACs inhibitory potency. Compound 11a (with 4-methoxybenzoyl as N-substituent in the cap and 4-(aminomethyl) benzoyl as the linker group) exhibited selectivity against HDAC1 to some extent, and showed potent antiproliferative activity against several tumor cell lines. In?vivo studies revealed that compound 11a displayed potent oral antitumor activity in both hematological tumor cell U937 xenograft model and solid tumor cell HCT116 xenograft model with no obvious toxicity. Further modification of benzamide 3, 11a and 19 afforded new thienyl and phenyl compounds (50a, 50b, 63a, 63b and 63c) with dramatic HDAC1 and HDAC2 dual selectivity, and the fluorine containing compound 56, with moderate HDAC3 selectivity.
- Li, Xiaoyang,Zhang, Yingjie,Jiang, Yuqi,Wu, Jingde,Inks, Elizabeth S.,Chou, C. James,Gao, Shuai,Hou, Jinning,Ding, Qinge,Li, Jingyao,Wang, Xue,Huang, Yongxue,Xu, Wenfang
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p. 185 - 206
(2017/04/21)
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- Synthesis of Oxazolylindole Alkaloids from Tryptamine and Tryptophan by Oxidation with 2,3-Dichloro-5,6-dicyanobenzoquinone
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When N-acyl derivatives of tryptamine and L-tryptophan methyl ester were treated with DDQ (2 equiv) in tetrahydrofuran or other anhydrous solvents, four consecutive reactions, dehydrogenation, nucleophilic cyclization, another dehydrogenation, and isomeri
- Yoshioka, Tadao,Mohri, Kunihiko,Oikawa, Yuji,Yonemitsu, Osamu
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p. 2252 - 2281
(2007/10/02)
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