Synthesis of Polysubstituted Imidazoles and Pyridines<i>via</i>Samarium(III) Triflate-Catalyzed [2+2+1] and [4+2] Annulations of Unactivated Aromatic Alkenes with Azides
作者:Yingchun Wang、Jiuling Li、Yan He、Yuyang Xie、Hengshan Wang、Yingming Pan
DOI:10.1002/adsc.201500584
日期:2015.10.12
Samarium(III) triflate-catalyzed [2+2+1] and [4+2] annulations have been identified for the preparation of fully substituted imidazoles and 2,3,5-trisubstituted pyridines from the readily available unactivatedaromaticalkenes and azidomethyl aromatics. These reactions proceeded smoothly with one- or two-nitrogen synthons to afford a range of two types of skeletally distinct N-heterocycles in good
μM), which was more potent than PCI-34058 (6) (IC50 = 0.31 μM), a known HDAC8 inhibitor. Molecular modeling suggested that the phenylthiomethyl group of C149 binds to a unique hydrophobic pocket of HDAC8, and the orientation of the phenylthiomethyl and hydroxamate moieties (fixed by the triazole moiety) is important for the potency and selectivity. The inhibitors caused selective acetylation of cohesin
Praseodymium(III)-Catalyzed Regioselective Synthesis of C<sub>3</sub>-N-Substituted Coumarins with Coumarins and Azides
作者:Jiu-ling Li、Da-chao Hu、Xin-ping Liang、Ying-Chun Wang、Heng-Shan Wang、Ying-ming Pan
DOI:10.1021/acs.joc.7b01410
日期:2017.9.1
A series of C3-N-substituted coumarins were synthesized in good yields directly from coumarins and azides in the presence of Pr(OTf)3 without any additives or ligands needed. The selected compounds 3a, 3c–e, 3g, 3i, 3q, 3u, and 3v exhibited good anticancer activities against MGC-803, A549, and NCI-H460 cell lines with IC50 in the range 8.75–38.54 μmol L–1.
We present a trifunctional scaffold designed for the solid-phase synthesis of trimodal compounds. This scaffold holds two alkyne arms in a free and TIPS-protected form for consecutive CuAAC (copper(I)-catalyzed azide–alkyne cycloaddition), one Fmoc-protected hydrazide arm for reaction with aldehydes, and one carboxylic acid arm with CF2 groups for attachment to the resin and 19F-NMR quantification. This scaffold was attached to a resin and derivatized with model azides and aliphatic, electron-rich or electron-poor aromatic aldehydes. We identified several limitations of the scaffold caused by the instability of hydrazones in acidic conditions, in the presence of copper during CuAAC, and when copper accumulated in the resin. We successfully overcame these drawbacks by optimizing synthetic conditions for the derivatization of the scaffold with aromatic aldehydes. Overall, the new trifunctional scaffold combines CuAAC and hydrazone chemistries, offering a broader chemical space for the development of bioactive compounds.
Transition-metal-free azide insertion of <i>N</i>-triftosylhydrazones using a non-metallic azide source
作者:Xueyu Li、Jin-Na Song、Swastik Karmakar、Ying Lu、Ye Lv、Peiqiu Liao、Zhaohong Liu
DOI:10.1039/d2cc05442f
日期:——
Benzylic azides, an important class of active organic synthons, were synthesized in high yields from the easily accessible N-triftosylhydrazones with stable TMSN3 under mild conditions. The reaction features high efficiency and excellent functional group tolerance, as illustrated by gram-scale synthesis and the synthesis of drug-like molecules. Mechanistic studies reveal that azidation occurs at the
苄基叠氮化物是一类重要的活性有机合成子,在温和条件下从易于获得的具有稳定 TMSN 3的N -triftosylhydrazone 以高产率合成。该反应具有高效和优异的官能团耐受性,如克级合成和类药分子的合成所示。机理研究表明,通过叠氮离子消除 N 2,在缺电子的重氮碳中发生叠氮化。